ALBERT

Description: Three-dimensional finite element model of the drilling process used for fixation of Salter–Harris type-3 fractures by using a K-wire Mechanical Sciences, 6, 147-154, 2015 Author(s): A. Gok, K. Gok, and M. B. Bilgin In this study, the drilling process was performed with Kirschner wire (K-wire) for stabilization after reduction of Salter–Harris (SH) type-3 epiphyseal fractures of distal femur. The study was investigated both experimentally and numerically. The numerical analyses were performed with finite element method (FEM), using DEFORM-3D software. Some conditions such as friction, material model and load and boundary must be identified exactly while using FEM. At the same time, an analytic model and software were developed, which calculate the process parameters such as drilling power and thrust power, heat transfer coefficients and friction coefficient between tool–chip interface in order to identify the temperature distributions occurring in the K-wire and bone model (Keklikoǧlu Plastik San.) material during the drilling process. Experimental results and analysis results have been found as consistent with each other. The main cutting force, thrust force, bone model temperature and K-wire temperature were measured as 80° N, 120° N, 69 °C and 61 °C for 400 rpm in experimental studies. The main cutting force, thrust force, bone model temperature and K-wire temperature were measured as 65° N, 87° N, 91 °C and 82 °C for 800 rpm in experimental studies. The main cutting force, thrust force, bone model temperature and K-wire temperature were measured as 85° N, 127° N, 72 °C and 67 °C for 400 rpm in analysis studies. The main cutting force, thrust force, bone model temperature and K-wire temperature were measured as 69° N, 98° N, 83 °C and 76 °C for 800 rpm in analysis studies. A good consistency was obtained between experimental results and finite element analysis (FEA) results. This proved the validity of the software and finite element model. Thus, this model can be used reliably in such drilling processes.

Description: Hybrid Position-Force Control of a Cable-Driven Parallel Robot with Experimental Evaluation Mechanical Sciences, 6, 119-125, 2015 Author(s): W. Kraus, P. Miermeister, V. Schmidt, and A. Pott For cable-driven parallel robots elastic cables are used to manipulate a mobile platform in the workspace. In this paper, we present a hybrid position-force control, which allows for applying defined forces on the environment and simultaneous movement along the surface. We propose a synchronous control of the cable forces to ensure the stability of the platform during movement. The performance of the controller is experimentally investigated regarding contact establishment and dynamic behavior during a motion on the cable robot IPAnema 3.

Description: An analysis of the particulate flow in cold spray nozzles Mechanical Sciences, 6, 127-136, 2015 Author(s): M. Meyer and R. Lupoi Cold Spray is a novel technology for the application of coatings onto a variety of substrate materials. In this method, melting temperatures are not crossed and the bonding is realized by the acceleration of powder particles through a carrier gas in a converging-diverging nozzle and their high energy impact over a substrate material. The critical aspect of this technology is the acceleration process and the multiphase nature of it. Three different nozzle designs were experimented under constant conditions and their performance simulated using Computational Fluid Dynamics tools. The Deposition Efficiency was measured using titanium as feedstock material and it was shown that it decreases with the cross-sectional throat area of the nozzle. Computational results based on a one-way coupled multiphase approach did not agree with this observation, while more sophisticated modelling techniques with two-way couplings can partially provide high-quality outcomes, in agreement with experimental data.

Description: Representation of the kinematic topology of mechanisms for kinematic analysis Mechanical Sciences, 6, 137-146, 2015 Author(s): A. Müller The kinematic modeling of multi-loop mechanisms requires a systematic representation of the kinematic topology, i.e. the arrangement of links and joints. A linear graph, called the topological graph, is used to this end. Various forms of this graph have been introduced for application in mechanism kinematics and multibody dynamics aiming at matrix formulations of the governing equations. For the (higher-order) kinematic analysis of mechanisms a simple yet stringent representation of the topological information is often sufficient. This paper proposes a simple concept and notation for use in kinematic analysis. Upon a topological graph, an order relation of links and joints is introduced allowing for recursive computation of the mechanism configuration. An ordering is also introduced on the topologically independent fundamental cycles. The latter is indispensable for formulating generically independent loop closure constraints. These are presented for linkages with only lower pairs, as well as for mechanisms with one higher kinematic pair per fundamental cycle. The corresponding formulation is known as cut-body and cut-joint approach, respectively.

Description: Successive dynamic programming and subsequent spline optimization for smooth time optimal robot path tracking Mechanical Sciences, 6, 245-254, 2015 Author(s): M. Oberherber, H. Gattringer, and A. Müller The time optimal path tracking for industrial robots regards the problem of generating trajectories that follow predefined end-effector (EE) paths in shortest time possible taking into account kinematic and dynamic constraints. The complicated tasks used in industrial applications lead to very long EE paths. At the same time smooth trajectories are mandatory in order to increase the service life. The consideration of jerk and torque rate restrictions, necessary to achieve smooth trajectories, causes enormous numerical effort, and increases computation times. This is in particular due to the high number of optimization variables required for long geometric paths. In this paper we propose an approach where the path is split into segments. For each individual segment a smooth time optimal trajectory is determined and represented by a spline. The overall trajectory is then found by assembling these splines to the solution for the whole path. Further we will show that by using splines, the jerks are automatically bounded so that the jerk constraints do not have to be imposed in the optimization, which reduces the computational complexity. We present experimental results for a six-axis industrial robot. The proposed approach provides smooth time optimal trajectories for arbitrary long geometric paths in an efficient way.

Description: Short communication: Automated testing of accelerometer transverse sensitivity with a flexure-based XY compliant stage Tiemin Li, Yunsong Du, Wei Ji, Zhihua Liu, and Chenguang Cai Mech. Sci., 7, 149-153, doi:10.5194/ms-7-149-2016, 2016 This paper presents the automated testing of accelerometer transverse sensitivity with a flexure-based compliant stage. An experimental platform is set up, and the circular tracking error is first obtained to verify the feasibility of the stage. The transverse sensitivity of the accelerometer under test is below 3 %. The difference of the transverse sensitivity under various frequencies is 0.4 %, while the difference of measured direction angle is 2.49, which validates the accuracy of the method.

Description: Towards developing product applications of thick origami using the offset panel technique Michael R. Morgan, Robert J. Lang, Spencer P. Magleby, and Larry L. Howell Mech. Sci., 7, 69-77, doi:10.5194/ms-7-69-2016, 2016 The offset panel technique (OPT) is a method which accommodates for the use of thick materials in origami models and preserves both the range of motion and the kinematics. This work explores new possibilities for origami-based product applications presented by the OPT. Examples are included to illustrate some of the capabilities of the OPT, including the use of various materials in a design and manipulation of panel geometry resulting in increased stiffness and strength in the design.

Description: The intradiscal failure pressure on porcine lumbar intervertebral discs: an experimental approach Mechanical Sciences, 6, 255-263, 2015 Author(s): A. R. G. Araújo, N. Peixinho, A. Pinho, and J. C. P. Claro The intervertebral disc is submitted to complex loading during its normal daily activities which are responsible for variations of the hydrostatic pressure in its structure. Thus, the determination of the magnitude of failure hydrostatic pressure is essential as a potential for the evaluation of the mechanisms that promote the weakening and the disruption of the annular fibers, commonly linked to herniation process on the spine column. However, few studies include the determination of the failure pressure on discs and the results are widely contradictory. Therefore, the objective of the present work is to determine the values of IDP that promotes the disc disruption. To achieve this goal, the tests were performed using a hydraulic cylinder that inflates the intervertebral disc. The results revealed a mean pressure failure of 0.62 ± 0.08 MPa for lumbar porcine samples ( n = 6). From this approach it can be concluded that (1) the potential for disc injury may exist at low pressures for lumbar porcine discs when compared several animal and human ones; (2) the rupture of human cervical and porcine lumbar annular fibers could occur for values of intradiscal pressure that are within the physiological range.

Description: 〈b〉The computation of bending eigenfrequencies of single-walled carbon nanotubes based on the nonlocal theory〈/b〉〈br〉 Jozef Bocko, Pavol Lengvarský, Róbert Huňady, and Juraj Šarloši〈br〉 Mech. Sci., 9, 349-358, https://doi.org/10.5194/ms-9-349-2018, 2018〈br〉 The paper is concerned to the computation of eigenfrequencies of single-walled carbon nanotubes (SWCNTs). Classical treatment, where the nanotube is approximated by beam theory, is replaced by the nonlocal theory of beam bending. The eigenfrequencies are computed by combination of analytical, as well as numerical methods for four types of boundary conditions. The results can be used for determination of Young’s modulus of homogenized SWCNTs from experimental measurements.

Description: Influence of gear loss factor on the power loss prediction Mechanical Sciences, 6, 81-88, 2015 Author(s): C. M. C. G. Fernandes, P. M. T. Marques, R. C. Martins, and J. H. O. Seabra In order to accurately predict the power loss generated by a meshing gear pair the gear loss factor must be properly evaluated. Several gear loss factor formulations were compared, including the author's approach. A gear loss factor calculated considering the load distribution along the path of contact was implemented. The importance of the gear loss factor in the power loss predictions was put in evidence comparing the predictions with experimental results. It was concluded that the gear loss factor is a decisive factor to accurately predict the power loss. Different formulations proposed in the literature were compared and it was shown that only few were able to yield satisfactory correlations with experimental results. The method suggested by the authors was the one that promoted the most accurate predictions.

Description: DAS-2D: a concept design tool for compliant mechanisms Omer Anil Turkkan and Hai-Jun Su Mech. Sci., 7, 135-148, doi:10.5194/ms-7-135-2016, 2016 Compliant mechanisms utilize the deformation of the elastic members to achieve the desired motion. Currently, design and analysis of compliant mechanisms rely on several commercial dynamics and finite element simulation tools. However, these tools do not implement the most recently developed theories in compliant mechanism research. DAS 2D is a conceptual design tool which integrates the recently developed pseudo-rigid-body models.

Description: Energy calculation model of an outgoing conveyor with application of a transfer chute with the damping plate Vieroslav Molnár, Gabriel Fedorko, Nikoleta Husáková, Ján Král' Jr., and Mirosław Ferdynus Mech. Sci., 7, 167-177, doi:10.5194/ms-7-167-2016, 2016 An energy calculation model of outgoing conveyor with the application of a transfer chute with the damping plate was used. The direction and orientation of material impact have a direct influence on the conveyor's energy intensity. For the effective operation of conveyor belts, attention must be paid to the construction of the area of movement, especially in the outgoing conveyor. The other issue to be considered is the direction and orientation of material impact.

Description: Two-temperature dual-phase-lags theory in a thermoelastic solid half-space due to an inclined load Ashraf M. Zenkour, Ahmed E. Abouelregal, Khaled A. Alnefaie, Nidal H. Abu-Hamdeh, Abdulmalik A. Aljinaidi, and Elias C. Aifantis Mech. Sci., 7, 179-187, doi:10.5194/ms-7-179-2016, 2016 This article addresses the thermoelastic interaction due to inclined load on a homogeneous isotropic half-space in context of two-temperature generalized theory of thermoelasticity with dual-phase-lags. The governing equations are solved by using the normal mode analysis. The variations of the displacement, stress, conductive temperature, and thermodynamic temperature distributions with the horizontal distance have been shown graphically.

Description: Coupled dynamic model and vibration responses characteristic of a motor-driven flexible manipulator system Mechanical Sciences, 6, 235-244, 2015 Author(s): Y. F. Liu, W. Li, X. F. Yang, Y. Q. Wang, M. B. Fan, and G. Ye Motor-driven flexible manipulator systems (MDFMSs) are widely used in industry robot fields. During the dynamic modeling, the separate investigation method which neglects the dynamic behavior of the driving motor will cause an error in the dynamic analysis of the flexible manipulator, especially with high-speed operations. This paper proposes a coupled dynamic model of the MDFMS in which the driving motor and flexible manipulator are considered as an integrated system, which can clearly reflect the influence of the dynamic effect of the driving motor. Based on the proposed dynamic model, the vibration responses of the flexible manipulator under different velocities, accelerations and structure parameters, as well as the effect mechanism of the driving motor on the vibration responses, are investigated. The results obtained in this paper contribute to the structure design, motion optimization and dynamic analysis of flexible manipulators.

Description: Model of a new joint thread for a drilling tool and its stress analysis used in a slim borehole Yu Wang, Bairu Xia, Zhiqiao Wang, and Chong Chai Mech. Sci., 7, 189-200, doi:10.5194/ms-7-189-2016, 2016 The drilling pipe used in slim-borehole drilling performs well due to its low cost and high efficiency. Good sealing properties and coupling strength are the two keys to ensure that the pipe works correctly. In this paper, a 68 mm diameter drilling pipe and its joint are developed. On the basis of Lame's theory, the contact model of the joint thread is represented under different axial force, makeup torque, and pressure difference between inner and outer pipe. This model provides a good reference for judging the quality of sealing of the joint thread. The analysis software ANSYS\Workbench is applied to stimulate the distribution of contact stress and sealing properties. A premium condition for drilling has been proposed, which provides a good theoretical basis for slim-borehole drilling.

Description: ECAP process improvement based on the design of rational inclined punch shapes for the acute-angled Segal 2θ-dies: CFD 2-D description of dead zone reduction Mechanical Sciences, 6, 41-49, 2015 Author(s): A. V. Perig and N. N. Golodenko This article is focused on a 2-D fluid dynamics description of punch shape geometry improvement for Equal Channel Angular Extrusion (ECAE) or Equal Channel Angular Pressing (ECAP) of viscous incompressible continuum through acute-angled Segal 2θ-dies with 2θ 〈 90°. It has been shown both experimentally with physical simulation and theoretically with computational fluid dynamics that for the best efficiency under the stated conditions, the geometric condition required is for the taper angle 2θ 0 of the inclined oblique punch to be equal to the 2θ angle between the inlet and outlet channels of the Segal 2θ-die. Experimentally and theoretically determined rational geometric condition for the ECAP punch shape is especially prominent and significant for ECAP through the acute angled Segal 2θ-dies. With the application of Navier-Stokes equations in curl transfer form it has been shown that for the stated conditions, the introduction of an oblique inclined 2θ 0 -punch results in dead zone area downsizing and macroscopic rotation reduction during ECAP of a viscous incompressible continuum. The derived results can be significant when applied to the improvement of ECAP processing of both metal and polymer materials through Segal 2θ-dies.

Description: Friction Stir Welding of AA2024-T3 plate – the influence of different pin types Mechanical Sciences, 6, 51-55, 2015 Author(s): D. Trimble, H. Mitrogiannopoulos, G. E. O'Donnell, and S. McFadden Some aluminium alloys are difficult to join using traditional fusion (melting and solidification) welding techniques. Friction Stir Welding (FSW) is a solid-state welding technique that can join two plates of material without melting the workpiece material. This proecess uses a rotating tool to create the joint and it can be applied to alumium alloys in particular. Macrostructure, microstructure and micro hardness of friction stir welded AA2024-T3 joints were studied. The influence of tool pin profile on the microstructure and hardness of these joints was examined. Square, triflute and tapered cylinder pins were used and results from each weldment are reported. Vickers micro hardness tests and grain size measurements were taken from the transverse plane of welded samples. Distinct zones in the macrostructure were evident. The zones were identified by transitions in the microstructure and hardness of weld samples. The zones identified across the sample were the the unaffected parent metal, the Heat Affected Zone (HAZ), the Thermo-Mechanicaly Affected Zone (TMAZ), and the Nugget Zone (NZ). Measured hardness values varied through each FSW zone. The hardness in each zone was below that of the parent material. The HAZ had the lowest hardness across the weld profile for each pin type tested. The cylindrical pin consistently produced tunnel and joint-line defects. Pin profiles with flat surface features and/or flutes produced consolidated joints with no defects.

Description: A parametric investigation of a PCM-based pin fin heat sink Mechanical Sciences, 6, 65-73, 2015 Author(s): R. Pakrouh, M. J. Hosseini, and A. A. Ranjbar This paper presents a numerical investigation in which thermal performance characteristics of pin fin heat sinks enhanced with phase-change materials (PCMs) designed for cooling of electronic devices are studied. The paraffin RT44 HC is poured into the aluminum pin fin heat sink container, which is chosen for its high thermal conductivity. The effects of different geometrical parameters, including number, thickness and height of fins, on performance are analyzed. Different aspects for heat transfer calculation, including the volume expansion in phase transition as well as natural convection in a fluid zone, are considered in the study. In order to validate the numerical model, previous experimental data and the present results are compared, and an acceptable agreement between these two is observed. Results show that increasing the number, thickness and height of fins leads to a significant decrease in the base temperature as well as operating time of the heat sink.

Description: On the infinitely-stable rotational mechanism using the off-axis rotation of a bistable translational mechanism Mechanical Sciences, 6, 75-80, 2015 Author(s): G. Hao and J. Mullins Different from the prior art concentrating on the primary translation of bistable translational mechanisms this paper investigates the off-axis rotation behaviour of a bistable translational mechanism through displacing the guided primary translation at different positions. Moment-rotation curves obtained using the nonlinear finite element analysis (FEA) for a case study show the multiple stable positions of the rotation under each specific primary motion, suggesting that an infinitely-stable rotational mechanism can be achieved by controlling the primary motion. In addition, several critical transition points have been identified and qualitative testing has been conducted for the case study.

Description: Experimental tests on operation performance of a LARM leg mechanism with 3-DOF parallel architecture Mechanical Sciences, 6, 1-8, 2015 Author(s): M. F. Wang, M. Ceccarelli, and G. Carbone In this paper, a prototype of a LARM leg mechanism is proposed by using a tripod manipulator and its operation performance is investigated through lab experimental tests. In particular, an experimental layout is presented for investigating operational performance. A prescribed motion with an isosceles trapezoid trajectory is used for characterizing the system behavior. Experiment results are analyzed for the purpose of operation evaluation and architecture design characterization of the tripod manipulator and its proposed prototype.

Description: Analytical model of temperature distribution in metal cutting based on Potential Theory Mechanical Sciences, 6, 89-94, 2015 Author(s): F. Klocke, M. Brockmann, S. Gierlings, and D. Veselovac Temperature fields evolving during metal cutting processes have also been of major interest. Temperatures in the tool influence the wear behaviour and hence costs, temperatures in the work-piece are directly responsible for later product quality. Due to the high significance of temperatures, many modelling attempts for temperature fields have been conducted, however failed to deliver satisfying results. The present paper describes a novel analytical model using complex functions based on potential theory. Relevant heat sources in metal cutting as well as changing material constants are considered. The model was validated by an orthogonal cutting process and different real machining processes.

Description: Modeling and control of piezoelectric inertia–friction actuators: review and future research directions Mechanical Sciences, 6, 95-107, 2015 Author(s): Y. F. Liu, J. Li, X. H. Hu, Z. M. Zhang, L. Cheng, Y. Lin, and W. J. Zhang This paper provides a comprehensive review of the literature regarding the modeling and control of piezoelectric inertia–friction actuators (PIFAs). Examples of PIFAs are impact drive mechanisms (IDMs) and friction-driving actuators (FDAs). In this paper, the critical challenges are first identified in modeling and control of PIFAs. Second, a general architecture of PIFAs is proposed to facilitate the analysis and classification of the literature regarding modeling and control of PIFAs. This general architecture covers all types of PIFAs (e.g., FDAs, IDMs) and thus serves as a general conceptual model of PIFAs. There is an additional benefit with this general architecture of PIFAs, namely that it is conducive to innovation in PIFAs, as new specific PIFAs may be designed in order to tailor to a specific application (for example, both FDAs and IDMs are viewed as specific PIFAs). Finally, the paper presents future directions in modeling and control for further improvement of the performance of PIFAs.

Description: Kinematic analysis of a novel 3-CRU translational parallel mechanism Mechanical Sciences, 6, 57-64, 2015 Author(s): B. Li, Y. M. Li, X. H. Zhao, and W. M. Ge In this paper, a modified 3-DOF (degrees of freedom) translational parallel mechanism (TPM) three-CRU (C, R, and U represent the cylindrical, revolute, and universal joints, respectively) structure is proposed. The architecture of the TPM is comprised of a moving platform attached to a base through three CRU jointed serial linkages. The prismatic motions of the cylindrical joints are considered to be actively actuated. Kinematics and performance of the TPM are studied systematically. Firstly, the structural characteristics of the mechanism are described, and then some comparisons are made with the existing 3-CRU parallel mechanisms. Although these two 3-CRU parallel mechanisms are both composed of the same CRU limbs, the types of freedoms are completely different due to the different arrangements of limbs. The DOFs of this TPM are analyzed by means of screw theory. Secondly, both the inverse and forward displacements are derived in closed form, and then these two problems are calculated directly in explicit form. Thereafter, the Jacobian matrix of the mechanism is derived, the performances of the mechanism are evaluated based on the conditioning index, and the performance of a 3-CRU TPM changing with the actuator layout angle is investigated. Thirdly, the workspace of the mechanism is obtained based on the forward position analysis, and the reachable workspace volume is derived when the actuator layout angle is changed. Finally, some conclusions are given and the potential applications of the mechanism are pointed out.

Description: Experimental study on transient behavior of embedded spiral-coil heat exchanger Mechanical Sciences, 6, 181-190, 2015 Author(s): E. I. Jassim Spiral coil offers a substantial amount of heat transfer area at a considerably low cost as it does not only have a lower wall resistance but it also achieves a better heat transfer rate in comparison to conventional U -tube arrangement. The general aim of the study is to assess different configurations of spiral coil heat exchangers that can eventually operate in a highly efficient manner. The paper documents the transient behavior of spiral-shaped tubes when the coil is embedded in a rectangular conducting slab. Different arrangements and number of turns per unit length, with fixed volumes, are considered in order to figure out the optimal configuration that maximizes the performance of the heat transfer. The implementation presented in the study is conducted to demonstrate the viability of the use of a large conducting body as supplemental heat storage. The system uses flowing water in the coil and stagnant water in the container. The copper-made coils situated in the center of the slab carries the cold fluid while the container fluid acts as a storage-medium. The water temperature at several depths of the container was measured to ensure uniformity in the temperature distribution of the container medium. Results have shown that the coil orientation, the number of loops, and the Reynolds number, substantially influence the rate of the heat transfer. The vertically-embedded spiral coil has a better performance than the horizontally-embedded spiral coil. Doubling the number of loops is shown to enhance the performance of the coil. Increasing Reynolds Number leads to better coil performance.

Description: A two-stage calibration method for industrial robots with joint and drive flexibilities Mechanical Sciences, 6, 191-201, 2015 Author(s): M. Neubauer, H. Gattringer, A. Müller, A. Steinhauser, and W. Höbarth Dealing with robot calibration the neglection of joint and drive flexibilities limit the achievable positioning accuracy significantly. This problem is addressed in this paper. A two stage procedure is presented where elastic deflections are considered for the calculation of the geometric parameters. In the first stage, the unknown stiffness and damping parameters are identified. To this end the model based transfer functions of the linearized system are fitted to captured frequency responses of the real robot. The real frequency responses are determined by exciting the system with periodic multisine signals in the motor torques. In the second stage, the identified elasticity parameters in combination with the measurements of the motor positions are used to compute the real robot pose. On the basis of the estimated pose the geometric calibration is performed and the error between the estimated end-effector position and the real position measured with an external sensor (laser-tracker) is minimized. In the geometric model, joint offsets, axes misalignment, length errors and gear backlash are considered and identified. Experimental results are presented, where a maximum end-effector error (accuracy) of 0.32 mm and for 90 % of the poses a maximum error of 0.23 mm was determined (Stäubli TX90L).

Description: Numerical simulation of buckling behavior of the buried steel pipeline under reverse fault displacement Mechanical Sciences, 6, 203-210, 2015 Author(s): J. Zhang, Z. Liang, C. J. Han, and H. Zhang Reverse fault movement is one of the threats for the structural integrity of buried oil-gas pipelines caused by earthquakes. Buckling behavior of the buried pipeline was investigated by finite element method. Effects of fault displacement, internal pressure, diameter-thick ratio, buried depth and friction coefficient on buckling behavior of the buried steel pipeline were discussed. The results show that internal pressure is the most important factor that affecting the pipeline buckling pattern. Buckling mode of non-pressure pipeline is collapse under reverse fault. Wrinkles appear on buried pressure pipeline when the internal pressure is more than 0.4 P max . Four buckling locations appear on the buried pressure pipeline under bigger fault displacement. There is only one wrinkle on the three locations of the pipeline in the rising formation, but more wrinkles on the fourth location. Number of the wrinkle ridges and length of the wavy buckling increase with the increasing of friction coefficient. Number of buckling location decreases gradually with the decreasing of diameter-thick ratio. A protective device of buried pipeline was designed for preventing pipeline damage crossing fault area for its simple structure and convenient installation. Those results can be used to safety evaluation, maintenance and protection of buried pipelines crossing fault area.

Description: Shape and force analysis of capillary bridge between two slender structured surfaces Mechanical Sciences, 6, 211-220, 2015 Author(s): Z. F. Zhu, J. Y. Jia, H. Z. Fu, Y. L. Chen, Z. Zeng, and D. L. Yu When a capillary bridge of a constant volume is formed between two surfaces, the shape of the liquid bridge will change as the separation between those surfaces is varied. To investigate the variable forces and Laplace pressure of the capillary bridge, as the shape the bridge evolves, a pseudo-three-dimensional force model of the capillary bridge is developed. Based on the characteristics of the slender structured surface, an efficient method is employed to directly solve the differential equations defining the shape of the capillary bridge. The spacing between the plates satisfying the liquid confined within the hydrophobic region of the structured surface is calculated. The method described in this paper can prevent meshing liquid surfaces such that, compared with Surface Evolver simulations, the computing speed is greatly improved. Finally, by comparing the results of the finite element simulations performed with Surface Evolver with those of the method employed in this paper, the practicality of the method is demonstrated.

Description: Thermal analysis of PCM containing heat exchanger enhanced with normal annular fines Mechanical Sciences, 6, 221-234, 2015 Author(s): M. J. Hosseini, M. Rahimi, and R. Bahrampoury In this study, the effect of fins' height and Stefan number on performance of a shell and tube heat exchanger which contains a phase change material is investigated numerically and experimentally. Melting time, solidification time, liquid mass fraction, melting and solidification front and temperature distribution in different directions (longitudinal, radial and angular) are among criteria for the heat exchangers' comparison. In order to generalize the comparison, melting and solidification fronts are studied for different sections of the shell, fin section and mid-section, for different fins' height during charging and discharging processes. The results show that, these two parameters play important roles in the heat exchanger performance. Increasing Stefan number, the melting time reduces; which exhibits a descending trend in rate when the fins are heightened. In addition, investigating both processes, it can be figured out that increasing fins' height influences the solidification time more significantly than melting.

Description: A comparison among different Hill-type contraction dynamics formulations for muscle force estimation F. Romero and F. J. Alonso Mech. Sci., 7, 19-29, doi:10.5194/ms-7-19-2016, 2016 In this work we analyze the main differences in muscle force production between the three different and widely used Hill-type muscle models (Soest and Bobbert, Silva-Kaplan and Thelen). As this work shows, there are slight differences between the obtained muscle efforts that arise from the assumptions made on each model. The computational effort or the control of the parameters involved in the experiments may determine the use of any of these descriptions of muscle tissue.

Description: Realisation of model reference compliance control of a humanoid robot arm via integral sliding mode control S. G. Khan and J. Jalani Mech. Sci., 7, 1-8, doi:10.5194/ms-7-1-2016, 2016 Human safety becomes critical when robot enters the human environment. Compliant control can be used to address some safety issues in human-robot physical interaction. This paper proposes an integral sliding mode controller (ISMC) based compliance control scheme for the Bristol Robotics Laboratory's humanoid BERT II robot arm. Apart from introducing a model reference compliance controller, the ISMC scheme is aimed to deal with the robot arm dynamic model's inaccuracies and un-modelled nonlinearities. The control scheme consists of a feedback linearization (FL) and an ISMC part. In addition, a posture controller has been incorporated to employ the redundant DOF and generate human like motion. The desired level of compliance can be tuned by selecting the stiffness and damping parameters in the sliding mode variable (compliance reference model). The results show that the compliant control is feasible at different levels for BERT II in simulation and experiment. The positioning control has been satisfactorily achieved and nonlinearities and un-modelled dynamics have been successfully overcome.

Description: Solving the dynamic equations of a 3- P RS Parallel Manipulator for efficient model-based designs M. Díaz-Rodríguez, J. A. Carretero, and R. Bautista-Quintero Mech. Sci., 7, 9-17, doi:10.5194/ms-7-9-2016, 2016 Three methods for formulating the dynamic model of parallel manipulators are compared in terms of their computational efficiency. The first two have been previously presented in the literature while the last one is introduced in this paper. Analysis of these numerical formulations provides a guideline for computational cost reduction for optimal design of this type of manipulator and for real-time embedded control.

Description: Guaranteed detection of the singularities of 3R robotic manipulators R. Benoit, N. Delanoue, S. Lagrange, and P. Wenger Mech. Sci., 7, 31-38, doi:10.5194/ms-7-31-2016, 2016 We propose two Interval Analysis based methods to characterize novel robots. Interval analysis theory allows us to consider intervals instead of values, making it possible to use computer algorithms, without the drawback of rounding errors. The first proposed method can isolate chosen interest points and is applied to the characteristic cusp and node points of 3R orthogonal manipulators. The second method encloses the robot available postures, giving complementary information on the novel robot.

Description: The intradiscal failure pressure on porcine lumbar intervertebral discs: an experimental approach A. R. G. Araújo, N. Peixinho, A. Pinho, and J. C. P. Claro Mech. Sci., 6, 255-263, doi:10.5194/ms-6-255-2015, 2015 The intervertebral disc is submitted to complex loading, which are responsible for variations of the hydrostatic pressure in its structure. The objective of the present work is to determine the internal pressure that promotes the porcine disc disruption. The tests were performed using a hydraulic cylinder that inflates the discs. It was concluded that potential for porcine disc injury may exist at low pressures for and the rupture could occur within intradiscal physiological pressures.

Description: Successive dynamic programming and subsequent spline optimization for smooth time optimal robot path tracking M. Oberherber, H. Gattringer, and A. Müller Mech. Sci., 6, 245-254, doi:10.5194/ms-6-245-2015, 2015 The time optimal path following problem for industrial robots regards the problem of generating trajectories that follow predefined end-effector paths in shortest time possible, taking into account kinematic and dynamic constraints. This paper proposes an approach to deal with arbitrary long geometric paths. Further a method is presented to achieve suitable smooth trajectories for an implementation on a real robot, in an easy way.

Description: Thermal analysis of PCM containing heat exchanger enhanced with normal annular fines M. J. Hosseini, M. Rahimi, and R. Bahrampoury Mech. Sci., 6, 221-234, doi:10.5194/ms-6-221-2015, 2015 In this study, the effect of fins’ height and Stefan number on performance of a shell and tube heat exchanger which contains a phase change material is investigated numerically and experimentally.Melting time, solidification time, liquid mass fraction, melting and solidification front and temperature distribution in different directions (longitudinal, radial and angular) are among criteria for the heat exchangers’ comparison.

Description: Numerical simulation of buckling behavior of the buried steel pipeline under reverse fault displacement J. Zhang, Z. Liang, C. J. Han, and H. Zhang Mech. Sci., 6, 203-210, doi:10.5194/ms-6-203-2015, 2015 Reverse fault movement is one of the threats for the structural integrity of buried oil-gas pipelines caused by earthquakes. Evaluation of the response of buried oil-gas pipelines crossing the faults can be used to safety evaluation, maintenance and seismic design. Buckling mode of non-pressure pipeline is collapse under reverse fault, while the buckling mode of pressure pipeline is wrinkle. A protective device was designed for preventing pipeline damage crossing fault area for its simple struct

Description: A two-stage calibration method for industrial robots with joint and drive flexibilities M. Neubauer, H. Gattringer, A. Müller, A. Steinhauser, and W. Höbarth Mech. Sci., 6, 191-201, doi:10.5194/ms-6-191-2015, 2015 Dealing with robot calibration the neglection of joint and drive flexibilities limit the achievable positioning accuracy significantly. This problem is addressed in this paper. A two stage procedure is presented where elastic deflections are considered for the calculation of the geometric parameters. In the first stage, the unknown stiffness and damping parameters are identified. To this end the model based transfer functions of the linearized system are fitted to captured frequency responses of the real robot. The real frequency responses are determined by exciting the system with periodic multisine signals in the motor torques. In the second stage, the identified elasticity parameters in combination with the measurements of the motor positions are used to compute the real robot pose. On the basis of the estimated pose the geometric calibration is performed and the error between the estimated end-effector position and the real position measured with an external sensor (laser-tracker) is minimized. In the geometric model, joint offsets, axes misalignment, length errors and gear backlash are considered and identified. Experimental results are presented, where a maximum end-effector error (accuracy) of 0.32 mm and for 90 % of the poses a maximum error of 0.23 mm was determined (Stäubli TX90L).

Description: Synthesis of PR-/RP-chain-based compliant mechanisms – design of applications exploiting fibre reinforced material characteristics U. Hanke, E.-C. Lovasz, M. Zichner, N. Modler, A. Comsa, and K.-H. Modler Mech. Sci., 6, 155-161, doi:10.5194/ms-6-155-2015, 2015 Compliant mechanisms have several advantages, especially their smaller number of elements and therefore less movable joints. The flexural members furthermore allow an integration of special functions like balancing or locking. Synthesis methods based on the rigid body model (Howell, 2001; Sönmezv, 2008) or topology optimisation (Zhou and Mandala, 2012) provide practical applications from the advantages of compliant elements. Beside these methods, a much simpler approach is the geometric-based synthesis (Ehlig et al., 2013) which is focused on solving guidance tasks by using RR-chain 1 -based compliant linkages. More compact compliant linkages can be build up by using only PR 2 or RP 3 chains. Therefore a tool is needed to extend the RR-chain-based approach. The necessary analysis of the compliant beam element can be done by numerical analysis and through experiments. Due to the validity of the Bernoulli beam model the elastic similitude can be specialised and a more general synthesis of compliant beam elements can be created. Altogether a generalised synthesis method can be created for handling different linkage structures as well integrating beam elements derived numerically or by measurement. The advances in this method are applied in the synthesis for a cupholder mechanism made of fiber reinforced material. 1 one link with two rotational joints (R) 2 one link with one frame fixed prismatic joint (P) and one moving rotational joint (R) 3 one link with one frame fixed rotational joint (R) and one moving prismatic joint (P)

Description: Experimental study on transient behavior of embedded spiral-coil heat exchanger E. I. Jassim Mech. Sci., 6, 181-190, doi:10.5194/ms-6-181-2015, 2015 The study addresses the significance of the coil geometry, number of turns, orientation, and mass flow on heat transfer performance. The outcome proves experimentally that such parameters have substantial impact on the rate of heat transfer as well as coil effectiveness. The study outcome is beneficial to wide technical sectors whose have interest in utilizing water pool as a coolant medium such as oil and gas companies, power plants, petrochemicals industries, and other firms.

Description: Shape and force analysis of capillary bridge between two slender structured surfaces Z. F. Zhu, J. Y. Jia, H. Z. Fu, Y. L. Chen, Z. Zeng, and D. L. Yu Mech. Sci., 6, 211-220, doi:10.5194/ms-6-211-2015, 2015 When a capillary bridge of a constant volume is formed between two surfaces, the shape of the liquid bridge will change as the separation between those surfaces is varied. To investigate the variable forces and Laplace pressure of the capillary bridge, as the shape the bridge evolves, a pseudo-three-dimensional force model of the capillary bridge is developed. Based on the characteristics of the slender structured surface, an efficient method is employed to directly solve the differential equations defining the shape of the capillary bridge. The spacing between the plates satisfying the liquid confined within the hydrophobic region of the structured surface is calculated. The method described in this paper can prevent meshing liquid surfaces such that, compared with Surface Evolver simulations, the computing speed is greatly improved. Finally, by comparing the results of the finite element simulations performed with Surface Evolver with those of the method employed in this paper, the practicality of the method is demonstrated.

Description: Representation of the kinematic topology of mechanisms for kinematic analysis A. Müller Mech. Sci., 6, 137-146, doi:10.5194/ms-6-137-2015, 2015 The kinematic modeling of multi-loop mechanisms requires a systematic representation of the kinematic topology, i.e. the arrangement of links and joints. A linear graph, called the topological graph, is used to this end. Various forms of this graph have been introduced for application in mechanism kinematics and multibody dynamics aiming at matrix formulations of the governing equations. For the (higher-order) kinematic analysis of mechanisms a simple yet stringent representation of the topological information is often sufficient. This paper proposes a simple concept and notation for use in kinematic analysis. Upon a topological graph, an order relation of links and joints is introduced allowing for recursive computation of the mechanism configuration. An ordering is also introduced on the topologically independent fundamental cycles. The latter is indispensable for formulating generically independent loop closure constraints. These are presented for linkages with only lower pairs, as well as for mechanisms with one higher kinematic pair per fundamental cycle. The corresponding formulation is known as cut-body and cut-joint approach, respectively.

Description: An analysis of the particulate flow in cold spray nozzles M. Meyer and R. Lupoi Mech. Sci., 6, 127-136, doi:10.5194/ms-6-127-2015, 2015 Cold Spray is a novel technology for the application of coatings, in which bonding is realized by the acceleration of powder particles through a carrier gas and their high speed impact over a substrate material. Different nozzle designs are shown experimentally to vary in deposition efficiency, which cannot be explained by standard computational simulations. In order to amend the modelling techniques, a stronger coupling of solid and gas phase is employed, which provided improved results.

Description: Hybrid Position-Force Control of a Cable-Driven Parallel Robot with Experimental Evaluation W. Kraus, P. Miermeister, V. Schmidt, and A. Pott Mech. Sci., 6, 119-125, doi:10.5194/ms-6-119-2015, 2015 For cable-driven parallel robots elastic cables are used to manipulate a mobile platform in the workspace. In this paper, we present a hybrid position-force control, which allows for applying defined forces on the environment and simultaneous movement along the surface. We propose a synchronous control of the cable forces to ensure the stability of the platform during movement. The performance of the controller is experimentally investigated regarding contact establishment and dynamic behavior during a motion on the cable robot IPAnema 3.

Description: B-spline parameterized optimal motion trajectories for robotic systems with guaranteed constraint satisfaction W. Van Loock, G. Pipeleers, and J. Swevers Mech. Sci., 6, 163-171, doi:10.5194/ms-6-163-2015, 2015 In this research the motion planning problem for systems that admit a polynomial description of the system dynamics through differential flatness is tackled by parameterizing the system's so-called flat output as a piecewise polynomial. Sufficient conditions on the spline coefficients are derived ensuring satisfaction of the operating constraints over the entire time horizon and an intuitive relaxation is proposed to tackle conservatism.

Description: Flexibility oriented design of a horizontal wrapping machine H. Giberti and A. Pagani Mech. Sci., 6, 109-118, doi:10.5194/ms-6-109-2015, 2015 Flying saw and cross cutter are techniques widely used to increase productivity but usually they are studied from a control point of view. This work highlights the kinematic and dynamic synthesis of a framework of a flying machine with the emphasis on the driving system chosen and the design parameter definition, in order to guarantee the required performance in terms of flexibility and high production volumes. The paper develops a flexibility oriented design to an horizontal wrapping machine.

Description: Modeling and control of piezoelectric inertia–friction actuators: review and future research directions Y. F. Liu, J. Li, X. H. Hu, Z. M. Zhang, L. Cheng, Y. Lin, and W. J. Zhang Mech. Sci., 6, 95-107, doi:10.5194/ms-6-95-2015, 2015 This paper provides a comprehensive review of the literature regarding the modelling and control of piezoelectric inertial-friction actuators (PIFAs). A general architecture of PIFA is proposed first to facilitate the analysis and classification of the literature. In addition, the paper presents the future directions in modelling and control of PIFAs for further improvement of their performance.

Description: Three-dimensional finite element model of the drilling process used for fixation of Salter–Harris type-3 fractures by using a K-wire A. Gok, K. Gok, and M. B. Bilgin Mech. Sci., 6, 147-154, doi:10.5194/ms-6-147-2015, 2015 In this study, the drilling process was performed with Kirschner wire (K-wire) for stabilization after reduction of Salter–Harris type-3 epiphyseal fractures of distal femur. The numerical analyses were performed with finite element method. An analytic model and software were developed to identify the temperature distributions occurring in the K-wire and sawbones material during drilling process. A good consistency was obtained between experimental results and finite element analysis results.

Description: Coupled dynamic model and vibration responses characteristic of a motor-driven flexible manipulator system Y. F. Liu, W. Li, X. F. Yang, Y. Q. Wang, M. B. Fan, and G. Ye Mech. Sci., 6, 235-244, doi:10.5194/ms-6-235-2015, 2015 The coupled dynamic model of the motor-driven flexible manipulator system (MDFMS) is proposed. It observes that the dynamic effect of the driving motor has a significant influence on the dynamic characteristic of the flexible manipulator, the Young's modulus of the flexible arm and the end effector have a considerable effect on the vibration responses, and larger velocities and accelerations have a suppressing effect on the influence of the driving motor.

Description: Biomechanical comparison using finite element analysis of different screw configurations in the fixation of femoral neck fractures K. Gok and S. Inal Mech. Sci., 6, 173-179, doi:10.5194/ms-6-173-2015, 2015 In this research, biomechanical behaviors of five different configurations of screws used for stabilization of femoral neck fracture under axial loading have been examined, and which configuration is best has been investigated. A point cloud was obtained after scanning the human femoral model with a three dimensional (3-D) scanner, and this point cloud was converted to a 3-D femoral model by Geomagic Studio software. Femoral neck fracture was modeled by SolidWorks software for five different configurations: dual parallel, triple parallel, triangle, inverted triangle and square, and computer-aided numerical analysis of different configurations were carried out by ANSYS Workbench finite element analysis (FEA) software. For each configuration, mesh process, loading status (axial), boundary conditions and material model were applied in finite element analysis software. Von Mises stress values in the upper and lower proximity of the femur and screws were calculated. According to FEA results, it was particularly advantageous to use the fixation type of triangle configuration. The lowest values are found as 223.32 MPa at the lower, 63.34 MPa at the upper proximity and 493.24 MPa at the screws in triangle configuration. This showed that this configuration creates minimum stress at the upper and lower proximity of the fracture line. Clinically, we believe that the lowest stress values which are created by triangle configuration encompass the most advantageous method. In clinical practices, it is believed that using more than three screws does not provide any benefit. Furthermore, the highest stresses are as follows: at upper proximity 394.79 MPa in triple parallel configuration, for lower proximity 651.2 MPa in square configuration and for screw 2459 MPa in inverted triangle.

Description: On the infinitely-stable rotational mechanism using the off-axis rotation of a bistable translational mechanism G. Hao and J. Mullins Mech. Sci., 6, 75-80, doi:10.5194/ms-6-75-2015, 2015 Different from the prior art concentrating on the primary translation of bistable translational mechanisms this paper investigates the off-axis rotation behaviour of a bistable translational mechanism through displacing the guided primary translation at different positions. Moment-rotation curves obtained using the nonlinear finite element analysis (FEA) for a case study show the multiple stable positions of the rotation under each specific primary motion, suggesting that an infinitely-stable rotational mechanism can be achieved by controlling the primary motion. In addition, several critical transition points have been identified and qualitative testing has been conducted for the case study.

Description: Analytical model of temperature distribution in metal cutting based on Potential Theory F. Klocke, M. Brockmann, S. Gierlings, and D. Veselovac Mech. Sci., 6, 89-94, doi:10.5194/ms-6-89-2015, 2015 Temperature fields evolving during metal cutting processes have been of major interest. Temperatures in the tool influence the wear behaviour and hence costs, temperatures in the work-piece are directly responsible for later product quality. Due to the high significance of temperatures, many modelling attempts for temperature fields have been conducted, however failed to deliver satisfying results. The present paper describes an analytical model using complex functions based on potential theory.

Description: Influence of gear loss factor on the power loss prediction C. M. C. G. Fernandes, P. M. T. Marques, R. C. Martins, and J. H. O. Seabra Mech. Sci., 6, 81-88, doi:10.5194/ms-6-81-2015, 2015 The importance of the gear loss factor in the power loss predictions was put in evidence comparing the predictions with experimental results. It was concluded that the gear loss factor is a decisive factor to accurately predict the power loss. Different formulations proposed in the literature were compared and it was shown that only few were able to yield satisfactory correlations with experimental results.

Description: Solving the dynamic equations of a 3- P RS Parallel Manipulator for efficient model-based designs M. Díaz-Rodríguez, J. A. Carretero, and R. Bautista-Quintero Mech. Sci., 7, 9-17, doi:10.5194/ms-7-9-2016, 2016 Three methods for formulating the dynamic model of parallel manipulators are compared in terms of their computational efficiency. The first two have been previously presented in the literature while the last one is introduced in this paper. Analysis of these numerical formulations provides a guideline for computational cost reduction for optimal design of this type of manipulator and for real-time embedded control.

Description: Dynamic synthesis of machine with slider-crank mechanism Mechanical Sciences, 6, 35-40, 2015 Author(s): A. A. Jomartov, S. U. Joldasbekov, and Yu. M. Drakunov In this paper we consider the formulation and solution of the task of a dynamic synthesis machine with an asynchronous electric motor and a slider-crank mechanism. The constant parameters of the slider-crank mechanism (mass and moments of inertia and centers of gravity of links) and the parameters of the electrical motor are defined. The laws of motion of the machine and kinematic parameters of the mechanism are considered as given. We have developed the method of optimal dynamic synthesis of the machine, which consists of an asynchronous electric motor and a slider-crank mechanism. The criterion of optimization of the dynamic synthesis of a machine is the root mean square sum of the moments of driving forces, the forces of resistance and inertia forces which are reduced to the axis of rotation of the crank. The method of optimal dynamic synthesis of a machine can be used in the design of new and the improvement of known mechanisms and machines.

Description: Dimensional synthesis of mechanical linkages using artificial neural networks and Fourier descriptors Mechanical Sciences, 6, 29-34, 2015 Author(s): N. Khan, I. Ullah, and M. Al-Grafi Dimensional synthesis of mechanisms to trace given paths is an important problem with no exact solution. In this paper, the problem is divided into representation of curve shape and learning the relation between curve shape and mechanism dimensions. Curve shape is represented by Fourier descriptors of cumulative angular deviation of the curve, which do not depend on the position or scale of the curve. An artificial neural network (ANN) is trained to learn the (unknown) relation between the Fourier descriptors of a planar curve and the dimensions of the mechanism tracing that curve. Presented with any simple, closed, planar curve, the ANN suggests the dimensions of a four-bar whose coupler curve is similar in shape. A local optimization procedure further refines the results. Examples presented indicate the method is successful as long as the curve shape is such that the mechanism is able to trace it.

Description: 〈b〉Design and dynamic analysis of metal rubber isolators between satellite and carrier rocket system〈/b〉〈br〉 Xibin Cao, Cheng Wei, Jiqiu Liang, and Lixu Wang〈br〉 Mech. Sci., 10, 71-78, https://doi.org/10.5194/ms-10-71-2019, 2019〈br〉 For launching satellite, with the needs of mobility and rapid-responsibility, the vehicle is used for launching. The system inevitably undergoes random vibrations caused by uneven ground excitation, while the camera and other high-precision payloads of the satellite cannot withstand the harsh mechanical environment without isolators. Due to the superior damping properties of MR, this paper designs the simple MR components and provides a feasible design method to absorb vibrations.

Description: 〈b〉Novel compliant wiper mechanism〈/b〉〈br〉 Raşit Karakuş and Engin Tanık〈br〉 Mech. Sci., 9, 327-336, https://doi.org/10.5194/ms-9-327-2018, 2018〈br〉 In this study, a compliant wiper mechanism is presented which can be used in land, air, and sea vehicles, particularly the automotive industry. The wiper mechanism is essentially a partially compliant four-bar mechanism. To the best of our knowledge, this is the first compliant wiper mechanism in the literature. After the theoretical calculations, a prototype is manufactured and an experiment is set up. The data obtained from the experimental setup are compared with the theoretical results.

Description: 〈b〉The nonlinear vibrations of orthogonal mechanism of vibrating table in view of friction〈/b〉〈br〉 Zharilkassin Iskakov, Kuatbay Bissembayev, and Nutpulla Jamalov〈br〉 Mech. Sci., 9, 307-325, https://doi.org/10.5194/ms-9-307-2018, 2018〈br〉 •With a large load on the vibrating table, the oscillation of the motor shaft angular velocity and the effect of friction on it are more significant. •Simulink model of the mechanism was developed for numerical calculations. •Friction increases the difference between the maximum and minimum values of the angular velocity and the coefficient of non-uniformity of rotation. •Sliding friction influences the frequency, the maximum and minimum values of the work-table kinematic parameters.

Description: 〈b〉Solution Region Synthesis Methodology of RCCC Linkages for Four Poses〈/b〉〈br〉 Jianyou Han and Yang Cao〈br〉 Mech. Sci., 9, 297-305, https://doi.org/10.5194/ms-9-297-2018, 2018〈br〉 The paper presents a solution region synthesis methodology for RCCC linkages. First, we couple the RC and CC dyads for obtaining all synthesis equations. Then using the solution region theory and Bertini software, all solutions for RCCC linkages can be obtained. The key contribution of this paper is that all solutions of RCCC linkages for four specific poses are obtained. Only one RCCC linkage can be synthesized by the methods published before;

Description: 〈b〉Mechatronic design and genetic-algorithm-based MIMO fuzzy control of adjustable-stiffness tendon-driven robot finger〈/b〉〈br〉 Izzat Al-Darraji, Ali Kılıç, and Sadettin Kapucu〈br〉 Mech. Sci., 9, 277-296, https://doi.org/10.5194/ms-9-277-2018, 2018〈br〉 The aim of this study is to integrate suggested control algorithms with a mechatronic design of underactuated adjustable stiffness finger for improving grasping operation. The designed robot finger system has the following main features: (1) preventing damage of objects during contact with phalanges, (2) having firm grasping, (3) adjusting grasped-forces on phalanges by stiffness of joints, and (4) implementing job independently without external control unit.

Description: 〈b〉Design and development of a novel monolithic compliant XY stage with centimeter travel range and high payload capacity〈/b〉〈br〉 Shixun Fan, Hua Liu, and Dapeng Fan〈br〉 Mech. Sci., 9, 161-176, https://doi.org/10.5194/ms-9-161-2018, 2018〈br〉 This article proposes a novel monolithic compliant spatial parallel XY stage (SPXYS). An important feature of the SPXYS lies in that it can deliver centimeter travel range and sustain large out-of-plane payload while possessing a compact structure, which makes the SPXYS suitable for some special applications such as Ultra-Violet Nanoimprint Lithography and soft-contact lithography.

Description: 〈b〉A Modified Prandtl-Ishlinskii Hysteresis Modeling Method with Load-dependent Delay for Characterizing Magnetostrictive Actuated Systems〈/b〉〈br〉 Ying Feng, Zhi Li, Subhash Rakheja, and Hui Jiang〈br〉 Mech. Sci., 9, 177-188, https://doi.org/10.5194/ms-9-177-2018, 2018〈br〉 The actuating precision of a micro-positioning system, driven by a magnetostrictive actuator, is adversely limited by its nonlinearities, particularly the output-input hysteresis, which are further affected by the operating load and input frequency. In this paper, the output-input properties of a magnetostrictive actuated system are experimentally characterized considering a wide range of operating frequencies and loads. The measured data revealed that the hysteresis behaviour is strongly affected with a change of operating load, and a modified Prandtl-Ishlinskii model with load-dependent delay is subsequently formulated to describe the nonlinear characteristics of the magnetostrictive actuated system in terms of major and minor loop hysteresis, and output magnitude and phase responses. The proposed model integrates a load-delay function related to the load mass with the Prandtl-Ishlinskii hysteresis model so as to fully describe the coupled nonlinear delay effects of the system output. The validity of the proposed model is demonstrated through comparisons with the experimental data for a range of operating loads and frequencies. It is shown that the proposed model can accurately describe the load-dependent hysteresis effects of the magnetostrictive actuated system up to certain input frequencies.

Description: 〈b〉Structural analysis of traditional Chinese hidden-keyhole padlocks〈/b〉〈br〉 Kuo-Hung Hsiao〈br〉 Mech. Sci., 9, 189-199, https://doi.org/10.5194/ms-9-189-2018, 2018〈br〉 Hidden-keyhole padlocks are reconfigurable mechanisms and a category of ancient Chinese locks. This work presents a useful procedure to indicate and analyze the topology variabilities of hidden-keyhole padlocks. The variable chains of hidden-keyhole padlocks are presented by using the representation of kinematic pairs, from which all topology variabilities of padlocks in the operation are derived. Four main types of hidden-keyhole padlocks are provided as examples to illustrate the procedure.

Description: 〈b〉Structural integrity investigation for RPV with various cooling water levels under pressurized melting pool〈/b〉〈br〉 Jianfeng Mao, Yunkai Liu, Shiyi Bao, Lijia Luo, Zhiming Lu, and Zengliang Gao〈br〉 Mech. Sci., 9, 147-160, https://doi.org/10.5194/ms-9-147-2018, 2018〈br〉 The traditional concepts on severe accident mitigation weren't seriously challenged until the occurrence of Fukushima accident on 2011, suggesting the structural behavior had not been appropriately assessed. Therefore, the paper tries to address the structure-related issue on determining whether structural safety can be maintained or not with the effect of various water levels and internal pressures created from core meltdown accident. The creep and plastic damages are interacted with each other

Description: 〈b〉Study on the large-displacement behaviour of a spiral spring with variations of cross-section, orthotropy and prestress〈/b〉〈br〉 Giuseppe Radaelli and Just L. Herder〈br〉 Mech. Sci., 9, 337-348, https://doi.org/10.5194/ms-9-337-2018, 2018〈br〉 Elastic systems that undergo large deformations are difficult to analyse because, while deforming, their mechanical properties change nonlinearly, which makes it difficult for designers to use them. In this work we make use of a graphical representation of the mechanical behaviour of a selected elastic object, a spiral spring, to facilitate the understanding of its behaviour. The use of these graphs is illustrated by generating peculiar examples of systems with many stable configurations.

Description: 〈b〉Analysis of Burr Formation in Low Speed Micro-milling of Titanium Alloy (Ti-6Al-4V)〈/b〉〈br〉 Gulfam Ul Rehman, Syed Husain Imran Jaffery, Mushtaq Khan, Liaqat Ali, Ashfaq Khan, and Shahid Ikramullah Butt〈br〉 Mech. Sci., 9, 231-243, https://doi.org/10.5194/ms-9-231-2018, 2018〈br〉 The research into micro machining of advanced alloys finds its applications in the aerospace, automotive, biomedical and healthcare and other industrial areas. One of the major concern is to produce parts at micro level without further rework, specifically surface finish. In order to achieve this, suitable process parameters and machining strategy needs to be identified for advanced alloy. The research presented here focuses on this aspect of the machining of Titanium Alloy.

Description: 〈b〉FE analysis of circular CFT columns considering bond-slip effect: A numerical formulation〈/b〉〈br〉 Ju-Young Hwang and Hyo-Gyoung Kwak〈br〉 Mech. Sci., 9, 245-257, https://doi.org/10.5194/ms-9-245-2018, 2018〈br〉 In this paper, a numerical model for the analysis of bond-slip occurring in concrete filled steel tube (CFT) columns is introduced. The introduced model considers the bond-slip effect by incorporation of the equivalent steel stiffness. Finally, the validity of the introduced numerical model is verified by comparing the experimental data with the analytical results for CFT columns subjected to axial force and bending moment.

Description: 〈b〉Posture adjustment of workpiece based on stepwise matching by self-adaptive differential evolution algorithm〈/b〉〈br〉 Lei Jiang, Yong Li, Yisheng Zou, Kun Tang, Yulong Fu, and Shuwen Ma〈br〉 Mech. Sci., 9, 267-276, https://doi.org/10.5194/ms-9-267-2018, 2018〈br〉 In order to improve the uniformity of workpiece allowance distribution, a stepwise workpiece matching adjustment method with contact inspection is developed.The stepwise matching includes the rough and fine matching processes. After matching, the spatial transformation matrixes 〈b〉R〈/b〉, 〈b〉T〈/b〉 and the adjustment values of machine tool can be obtained accurately. At last, some experiments were presented to demonstrate the performance of the method.

Description: 〈b〉Hysteresis analysis of a notched continuum manipulator driven by tendon〈/b〉〈br〉 Hong-Jian Yu, Wen-Long Yang, Zheng-Xin Yang, Wei Dong, Zhi-Jiang Du, and Zhi-Yuan Yan〈br〉 Mech. Sci., 9, 211-219, https://doi.org/10.5194/ms-9-211-2018, 2018〈br〉 Continuum manipulators are widely used in minimally invasive surgical robot systems (MISRS) because of their flexibility and compliance, while their modelling and control are relatively difficult and complex. This paper proposes an improved hysteresis model of a notched continuum manipulator based on the classical Bouc–Wen model, which can reduce errors and increase the accuracy of the kinematic-mechanics coupled model. Then parameters are identified by the mean of genetic algorithm (GA). Hysteresis phenomenon of the mentioned manipulator is actually caused by many factors such as the hysteresis property of Hyperelastic Nitinol Alloy (HNA), the elastic deformation of tendon and the friction between the tendon and the tube. The results of both static and dynamic experiments show that the introduced hysteresis model can eliminate the positional difference between forward and reverse bending processes, and thus improve the forecast precision of deformation during motion. This model can also be used to compensate modelling errors caused by hysteresis of other similar systems.

Description: 〈b〉A modified ball screw lapping method and optimized lapping factors for ideal surface quality〈/b〉〈br〉 Leilei Zhao, Hutian Feng, and Jun Jin〈br〉 Mech. Sci., 9, 221-230, https://doi.org/10.5194/ms-9-221-2018, 2018〈br〉 The aim of this study is finding a modified lapping method to improve the lapping effect, increase efficiency and change the present labor-intensive situation. In this study, a modified lapping tool was designed and it was designed to fit on a specially designed friction torque test machine. In addition, a set of orthogonal experiments were designed to capture the effects of four main lapping factors: friction torque, abrasive particulate size, lapping time and the rotational speed.

Description: 〈b〉Worm gear efficiency model considering misalignment in electric power steering systems〈/b〉〈br〉 Seong Han Kim〈br〉 Mech. Sci., 9, 201-210, https://doi.org/10.5194/ms-9-201-2018, 2018〈br〉 This study proposes a worm gear efficiency model considering misalignment in electric power steering systems. Geometrical and tribological analyses were performed and in order for validation of the model, a worm gear was prepared and the efficiency of the worm gear was predicted by the model. As the final procedure of the study, a worm gear efficiency measurement system was set and the efficiency of the worm gear was measured and the results were compared with the predicted result.

Description: 〈b〉Location of unbalance mass and supporting bearing for different type of balance shaft module〈/b〉〈br〉 Chan-Jung Kim〈br〉 Mech. Sci., 9, 259-266, https://doi.org/10.5194/ms-9-259-2018, 2018〈br〉 The conceptual design of balance shaft was very important process as how to locate the unbalance masses and corresponding supporting bearings. In this paper, the optimal conceptual balance shaft model was derived by using proposed objective functions for an inline 3-cylinder engine and an inline 4-cylinder one, respectively. Two kinds of optimal model were derived from simulations and efficient design guidelines was finally explained with design flowchart.

Description: 〈b〉Module-based structure design of wheeled mobile robot〈/b〉〈br〉 Zirong Luo, Jianzhong Shang, Guowu Wei, and Lei Ren〈br〉 Mech. Sci., 9, 103-121, https://doi.org/10.5194/ms-9-103-2018, 2018〈br〉 A systematic method was proposed for the synthesis and creative design of novel structures that can be used to build wheeled mobile robot. The proposed method has led to 236 new design schemes. Mathematical models and a software platform were developed to provide appropriate and intuitive tools for simulating and evaluating performance of the wheeled robots. Physical prototypes of sample wheeled robots were developed and tested, proving and validating the principle and methodology presented.

Description: 〈b〉Modelling, simulation and experiment of the spherical flexible joint stiffness〈/b〉〈br〉 Songyu Li, Liquan Wang, Shaoming Yao, Peng Jia, Feihong Yun, Wenxue Jin, and Dong Lv〈br〉 Mech. Sci., 9, 81-89, https://doi.org/10.5194/ms-9-81-2018, 2018〈br〉 The spherical flexible joint is used to connect the Tension Leg Platform to the seabed. It can provide low shear stiffness while bearing high compression force. So the research on the stiffness of flexible joint is necessary. The linear rotational stiffness of the flexible joint is formulated and FEM is used to verify the analytical solution. The increase of Poisson's ratio of the rubber layers will enhance the vertical compression stiffness but barely have effect on the rotational stiffness.

Description: 〈b〉Tool selection method based on transfer learning for CNC machines〈/b〉〈br〉 Jingtao Zhou, Han Zhao, Mingwei Wang, and Bingbo Shi〈br〉 Mech. Sci., 9, 123-146, https://doi.org/10.5194/ms-9-123-2018, 2018〈br〉 Due to the time-consuming and inefficient traditional tool selection method based on the human experience, we apply transfer learning to CNC tool selection issue in the field of industrial manufacturing. A unified expression of expert experience and process case is given in a more complex environment and then we improve the algorithm. The results show that the method we proposed can facilitate tool selection.

Description: 〈b〉Mechanical behaviour of a creased thin strip〈/b〉〈br〉 Jie Liu, Shanqing Xu, Guilin Wen, and Yi Min Xie〈br〉 Mech. Sci., 9, 91-102, https://doi.org/10.5194/ms-9-91-2018, 2018〈br〉 The mechanical behaviour of a creased thin strip under opposite-sense bending was investigated，revealing that a simple crease could significantly alter the overall mechanical behaviour of a thin strip. The influence of the geometrical parameters on the mechanical behaviour of the creased strip was studied. The deformation patterns of the thin strips from the finite element simulations were verified by physical models made from thin metal strips.

Description: 〈b〉A new manual wheelchair propulsion system with self-locking capability on ramps〈/b〉〈br〉 Gaspar Rodríguez Jiménez, David Rodríguez Salgado, Francisco Javier Alonso, and José María del Castillo〈br〉 Mech. Sci., 9, 359-371, https://doi.org/10.5194/ms-9-359-2018, 2018〈br〉 The present work describes the design and build of a new completely mechanical propulsion system for manual wheelchairs for use in ascending or descending long ramps. The design is characterized by a self-locking mechanism that activates automatically to brake the chair when the user stops pushing. The main component of the propulsion system is a planetary gear train that can self-lock, this means that the user does not need to activate external brakes.

Description: 〈b〉Rotational Constraint between Beams in 3-D Space〈/b〉〈br〉 Hamid Reza Motamedian and Artem Kulachenko〈br〉 Mech. Sci., 9, 373-387, https://doi.org/10.5194/ms-9-373-2018, 2018〈br〉 This paper presents a way to model the rotational constraint between beam elements in 3-D space. Beam elements are models used to simulate the behavior of slender objects. Such objects can be found for e.g. in bridges, space structures, robots, and networks of fibers (paper, cloth, biological tissue, etc). In many cases, beam elements are welded or bonded together. To model this bonding, the relative displacements and rotations shall be limited at the contact point using appropriate constraints.

Description: 〈b〉Energy saving optimal design and control of electromagnetic brake on passenger car〈/b〉〈br〉 Donghai Hu, Yanzhi Yan, and Xiaoming Xu〈br〉 Mech. Sci., 10, 57-70, https://doi.org/10.5194/ms-10-57-2019, 2019〈br〉 In this article, prediction models of the braking performance and power consumption of electromagnetic brake are established and their accuracies are verified on the hardware in the loop simulation platform. The electromagnetic brake is designed aiming at reducing the energy consumption and the energy saving control method of electromagnetic brake is also proposed.

Description: 〈b〉Compact design of a novel precise cable drive mechanism with high precision and large torque-to-weight ratio〈/b〉〈br〉 Xin Xie, Xianliang Jiang, Shixun Fan, and Dapeng Fan〈br〉 Mech. Sci., 10, 47-56, https://doi.org/10.5194/ms-10-47-2019, 2019〈br〉 Since the common layout of Precise cable drive, Single-Input Single-Output (SISO) spur gear configuration, suffers from low torque-to-weight ratio and loose structure, this paper proposes a novel transmission configuration. It combines the advantages of Multiple-Input Single-Output (MISO) configuration and bevel gear configuration. The proposed technologies could have strong technological implications in some special applications such as stabilized sighting system or infrared imaging seeker.

Description: 〈b〉Design and optimization of full decoupled micro/nano-positioning stage based on mathematical calculation〈/b〉〈br〉 Zhigang Wu, Yangmin Li, and Min Hu〈br〉 Mech. Sci., 9, 417-429, https://doi.org/10.5194/ms-9-417-2018, 2018〈br〉 This paper is done based on the research result for my research program. Testing results indicate that the maximal cross coupling of the 2-DOF micro-positioning stage is less than 0.1% under the full workspace with the natural frequency of 348.31Hz. The purpose of all work is to design a compliant mechanism for applying the micro-nano-positioning system. And that this work also extends my research interest in my PhD period.

Description: 〈b〉detasFLEX – A computational design tool for the analysis of various notch flexure hinges based on non-linear modeling〈/b〉〈br〉 Stefan Henning, Sebastian Linß, and Lena Zentner〈br〉 Mech. Sci., 9, 389-404, https://doi.org/10.5194/ms-9-389-2018, 2018〈br〉 A novel computational design tool to calculate the elasto-kinematic flexure hinge properties is presented. Four hinge contours are implemented. It is shown, that FEM results correlate well with the analytical design tool results. For a given deflection angle of 10° and a corner-filleted contour, the deviations of the bending stiffness are between 0.1 % and 9.4 %. The design tool can be beneficial for the accelerated and systematic synthesis of compliant mechanisms with optimized flexure hinges.

Description: 〈b〉Kinematic analysis and optimization of a planar parallel compliant mechanism for self-alignment knee exoskeleton〈/b〉〈br〉 Yijun Niu, Zhibin Song, and Jiansheng Dai〈br〉 Mech. Sci., 9, 405-416, https://doi.org/10.5194/ms-9-405-2018, 2018〈br〉 In rehabilitation, the widely existing misalignment between human limb and exoskeleton causes discomfort even danger. To alleviate the misalignment in lower extremity exoskeleton, this study proposes a compliant parallel mechanism, which has the potential to automatically change its configuration to make exoskeleton knee joint fit the human joint movements. And the self-alignment performance of the mechanism is validated via conducting a series of experiments under different working conditions.

Description: Effect of cutting speed parameters on the surface roughness of Al5083 due to recrystallization Elias Rezvani, Hamid Ghayour, and Masoud Kasiri Mech. Sci., 7, 85-91, doi:10.5194/ms-7-85-2016, 2016 the effect of machining parameters and recrystallization on surface quality of Al5083 has been investigated. In order to achieve minimum surface roughness of aluminum 5083 samples, statistical test design method of "full factorial" was used. In order to achieve the phenomenon of recrystallization, aluminum 5083 samples were set under 50 % cold rolling mechanical operations. roughness, tensile, and microstructure tests indicated the reduction of surface roughness in crystallized sample.

Description: A computationally efficient model to capture the inertia of the piezoelectric stack in impact drive mechanism in the case of the in-pipe inspection application Jin Li, Chang Jun Liu, Xin Wen Xiong, Yi Fan Liu, and Wen Jun Zhang Mech. Sci., 7, 79-84, doi:10.5194/ms-7-79-2016, 2016 Our work mainly focuses on the dynamic modeling of a piezoelectric actuator (PA) in the impact drive mechanism in the case of the in-pipe inspection application. The novel model we have developed is able to capture the inertia of the PA and the feature of this model is its computational efficiency with reasonable accuracy. This study has concluded that the inertia of the PA in such a robot can significantly affect the accuracy of the entire model of IDM.

Description: Multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge Zhijiang Du, Miao Yang, and Wei Dong Mech. Sci., 7, 127-134, doi:10.5194/ms-7-127-2016, 2016 Flexure hinges made of superelastic materials is a promising candidate to enhance the movability of compliant mechanisms. In this paper, we focus on the multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge. The objective is to determine a set of optimal geometric parameters that maximizes the motion range and the relative compliance of the flexure hinge and minimizes the relative rotation error during the deformation as well. Firstly, the paper presents a new type of ellipse-parabola shaped flexure hinge which is constructed by an ellipse arc and a parabola curve. Then, the static responses of superelastic flexure hinges are solved via non-prismatic beam elements derived by the co-rotational approach. Finite element analysis (FEA) and experiment tests are performed to verify the modeling method. Finally, a multi-objective optimization is performed and the Pareto frontier is found via the NSGA-II algorithm.

Description: Remarks on the classification of wheeled mobile robots Christoph Gruber and Michael Hofbaur Mech. Sci., 7, 93-105, doi:10.5194/ms-7-93-2016, 2016 The subject of this work is modeling of single-bodied wheeled mobile robots. In the past, it was shown that the kinematics of each such robot can be modeled by one out of only five different generic models. However, the precise conditions under which a model is the proper description of the kinematic capabilities of a robot were not clear. These shortcomings are eliminated in this work, leading to a simple procedure for model selection and a classification of singularities.

Description: Solving the double-banana rigidity problem: a loop-based approach Florian Simroth, Huafeng Ding, and Andrés Kecskeméthy Mech. Sci., 7, 107-117, doi:10.5194/ms-7-107-2016, 2016 The "double-banana" problem is a counter-example of Laman's rigidity condition formula for which existing standard Degree of Freedom counting formulas fail. The novelty of the approach for rigidity detection presented in this paper consists in regarding the structure not as a set of joint-connected bodies but as a set of interconnected loops. By tracking isolated DOFs such as those arising between pairs of spherical joints, rigidity/mobility subspaces can be identified successfully.

Description: Mechanical design, analysis and testing of a large-range compliant microgripper Yilin Liu and Qingsong Xu Mech. Sci., 7, 119-126, doi:10.5194/ms-7-119-2016, 2016 This paper presents the design and testing of a new large-range compliant microgripper. The gripper arms not only provide large gripping range but deliver approximately rectilinear movement as the displacement in nonworking direction is extremely small. The large gripping range is enabled by a dual-stage flexure amplifier to magnify the stroke of piezoelectric actuator. Finite-element analysis simulation study has been conducted. A prototype of the gripper is developed for experimental testing.

Description: A representation of the configurations and evolution of metamorphic mechanisms W. Zhang, X. Ding, and J. Liu Mech. Sci., 7, 39-47, doi:10.5194/ms-7-39-2016, 2016 The paper introduces a comprehensive symbolic matrix representation for characterizing the topology of a metamorphic mechanism using general information concerning links and joints. Operations on the matrices of the adjacent configuration mechanisms are defined to construct an origin matrix and joint variation matrices. The representation of the configurations and evolution of metamorphic Mechanisms provides a foundation for the analysis and synthesis of novel metamorphic mechanisms.

Description: Output decoupling property of planar flexure-based compliant mechanisms with symmetric configuration Y. S. Du, T. M. Li, Y. Jiang, and J. L. Zhang Mech. Sci., 7, 49-59, doi:10.5194/ms-7-49-2016, 2016 This paper presents the output decoupling property of flexure-based mechanisms. The model shows that mechanisms are output decoupled when they are symmetry about two perpendicular axes or when they are composed of either three or an even number of identical limbs distributed evenly around the center. The results obtained from the proposed model and FEA are almost same, which validates the model. It provides a reference point for further studies on the design and optimization of mechanisms.

Description: A continuum anisotropic damage model with unilateral effect A. Alliche Mech. Sci., 7, 61-68, doi:10.5194/ms-7-61-2016, 2016 A continuum damage mechanics model has been derived within the framework of irreversible thermodynamics with internal variables in order to describe the behaviour of quasi-brittle materials under various loading paths. The anisotropic character induced by the progressive material degradation is explicitly taken into account, and the Helmholtz free energy is a scalar function of the basic invariants of the second order strain and damage tensors. The elastic response varies depending on the closed or open configuration of defects. The constitutive laws derived within the framework of irreversible thermodynamics theory display a dissymmetry as well as unilateral effects under tensile and compressive loading conditions. This approach verifies continuity and uniqueness of the potential energy. An application to uniaxial tension-compression loading shows a good adequacy with experimental results when available, and realistic evolutions for computed stresses and strains otherwise.

Description: Research on a Hierarchical and Simultaneous Gravity Unloading Method for Antenna Pointing Mechanism Guoyong Yang, Hongguang Wang, Jizhong Xiao, Zuowei Wang, and Lie Ling Mech. Sci., 8, 51-63, doi:10.5194/ms-8-51-2017, 2017 This paper presents a gravity unloading facility to simulate micro-gravity environment of space. The facility unloads the gravity of artificial antenna of satellite and its pointing mechanism to test the performance of the pointing mechanism on the ground. The facility consists of two layers to unload gravity hierarchically and simultaneously while the antenna pointing mechanism consists of two joints. The calculation, simulation and experiments all show the effectiveness of the method applied.

Description: Development of a solar concentrator with tracking system Flávia V. Barbosa, João L. Afonso, Filipe B. Rodrigues, and José C. F. Teixeira Mech. Sci., 7, 233-245, doi:10.5194/ms-7-233-2016, 2016 Although Portugal is a country with high levels of irradiation, the investment in solar concentrator systems is virtually non-existent. Considering the solar potential and the high efficiency of solar dishes, this work pretends to demonstrate the added-value of the application of this technology. The development of a solar dish concentrator with a low cost tracking system allows to expand its application and disseminate the system into a wider market.

Description: An experimental characterization of human falling down Libo Meng, Marco Ceccarelli, Zhangguo Yu, Xuechao Chen, and Qiang Huang Mech. Sci., 8, 79-89, https://doi.org/10.5194/ms-8-79-2017, 2017 This paper presents results of an experimental investigation on the falling down of human body in order to identify significant characteristics and parameters. Vision tracking system and suitable sensors to monitor the falling motion. Tests are discussed with results from lab tests that give both behavior and values of the biomechanics of falling down of human body.

Description: Automated local line rolling forming and simplified deformation simulation method for complex curvature plate of ships Yao Zhao, Changcheng Hu, Hongbao Dong, and Hua Yuan Mech. Sci., 8, 137-154, https://doi.org/10.5194/ms-8-137-2017, 2017 A three-dimensional elastoplastic finite element method was first employed to perform numerical computations for local line rolling forming, according to the characteristics of strain distributions, a simplified deformation simulation method, based on the deformation obtained by applying strain was presented. This simplified deformation simulation method was verified to provide high computational accuracy, and this could result in a substantial reduction in calculation time.

Description: Design and Modelling of a Cable-Driven Parallel-Series Hybrid Variable Stiffness Joint Mechanism for Robotics Cihat Bora Yigit and Pinar Boyraz Mech. Sci., 8, 65-77, https://doi.org/10.5194/ms-8-65-2017, 2017 A new joint mechanism design is presented in this study which has a potential use in robotics, particularly in humanoid robot designs, because of its variable stiffness characteristics, lightweight and remotely-actuated structure. A helical spring inside the mechanism brings compliance which increases the safety. The spring is analyzed with a method proposed in the paper and verified by FEM. The kinematic and the dynamic models are obtained and experimentally validated.

Description: Performance of a Low Speed Axial Compressor Rotor Blade Row under Different Inlet Distortions Reza Taghavi Zenouz, Mehran Eshaghi Sir, and Mohammad Hosein Ababaf Behbahani Mech. Sci., 8, 127-136, https://doi.org/10.5194/ms-8-127-2017, 2017 Performance of gas turbine engines are strongly dependent on entrance air flow conditions. In the current work, responses of an axial compressor isolated rotor blade row to various inlet distortions are investigated utilizing computational fluid dynamic technique. Distortions are imposed by five screens of different geometries but with the same blockage ratio. Results showed that the worst cases belong to non-symmetric blockages, i.e., those of partial circumferential configurations.

Description: General design equations for the rotational stiffness, maximal angular deflection and rotational precision of various notch flexure hinges Sebastian Linß, Philipp Schorr, and Lena Zentner Mech. Sci., 8, 29-49, https://doi.org/10.5194/ms-8-29-2017, 2017 Notch flexure hinges are often used as revolute joints in high-precise compliant mechanisms. Therefore, this paper presents design equations for the calculation of the rotational stiffness, maximal angular elastic deflection and rotational precision of various notch flexure hinges in dependence of the hinge parameters and the load. Four flexure hinge contours are investigated, the semi-circular, the corner-filleted, the elliptical, and the recently introduced bi-quadratic polynomial contour.

Description: A two-dimensional electron gas sensing motion of a nanomechanical cantilever Andrey Shevyrin and Arthur Pogosov Mech. Sci., 8, 111-115, https://doi.org/10.5194/ms-8-111-2017, 2017 The low-dimensional electron systems made from semiconductor heterostructures are known mostly as a base for studying the mesoscopic electron-transport phenomena. However, they can also be used for creation of nanoelectromechanical systems combining non-trivial electron transport and mechanical degrees of freedom. In the present paper, we propose a quantitative physical model describing the piezoelectric electromechanical coupling in nanomechanical resonators with a two-dimensional electron gas.