ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Bingley : Emerald
    Journal of quality in maintenance engineering 8 (2002), S. 226-238 
    ISSN: 1355-2511
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology , Economics
    Notes: The variations introduced during the production and maintenance of rotating machinery components are correlated with the vibration and noise emanating from the final system during its operational lifetime. Vibration and noise are especially unacceptable elements in high-risk systems such as helicopters and aircraft engines, resulting in premature component degradation and a potentially unsafe flying environment. In such applications, individual components often are subject to 100 per cent inspection following production and during operation through rigorous maintenance, resulting in increased product development cycles and high production and operation costs. In this work, the aim is to provide engineers with a technique to evaluate vibration modes and levels for each component or subsystem prior to putting them into operation. This paper presents a preliminary investigation of the correlation of manufacturing and assembly variations with vibrations, using an experimental test rig. A factorial design is used to study the effects of various factors. Challenges in developing a process monitoring and inspection methodology to predict performance quality are identified, followed by a discussion of future work.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Engineering computations 20 (2003), S. 559-582 
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: Materials commonly involve microstructure. Clay is a microinhomogeneous material with nanoscale microstructure. Key issues to understand the behavior of such a finely microinhomogeneous material are as follows: the microstructure is characterized in detail, the local distribution of material properties is identified by experiment or simulation, and the microscale characteristics are related to the macroscale behavior by a seamless manner. For characterizing a microstructure of bentonite, we introduce a conforcal laser scanning microscope (CLSM) together with SEM. By CLSM we can specify a 3D configuration under atmospheric condition. Properties of water-saturated bentonite are mainly controlled by hydrated montmorillonite, which is the major clay mineral of bentonite. Smectite minerals including montmorillonite are extremely fine and poorly crystallized, so it is difficult to determine the properties by experiment. We inquire into the physicochemical properties by a molecular dynamics simulation method. Then, we develop a multiscale homogenization method to extend the microscopic characteristics to the macroscopic behavior. We show numerical examples of a diffusion problem.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Bingley : Emerald
    Journal of quality in maintenance engineering 9 (2003), S. 144-159 
    ISSN: 1355-2511
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology , Economics
    Notes: This paper presents experiment results that examine the validity of extracting blade vibration signature from the shaft torsional vibration signals. A special test rig was designed and manufactured for this objective. A set of strain gages were bonded to the shaft and to the blades to measure the shaft twisting and blade bending deformations respectively. A controlled frequency exciter excited the blade vibration. The shaft torsional and blade bending vibration signals were simultaneously recorded and presented in the time and frequency domains. The blade bending vibration frequencies appeared dominantly in the shaft torsional vibration signals for all blade vibration frequencies up to 100Hz. For frequencies higher than 100Hz, less sensitivity of the torsional vibration to blade vibration was observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Bingley : Emerald
    Journal of quality in maintenance engineering 9 (2003), S. 351-375 
    ISSN: 1355-2511
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology , Economics
    Notes: Due to the non-stationarity of vibration signals resulting from either varying operating conditions or natural deterioration of machinery, both the frequency components and their magnitudes vary with time. However, little research has been done on the parameter estimation of time-varying multivariate time series models based on adaptive filtering theory for condition-based maintenance purposes. This paper proposes a state-space model of non-stationary multivariate vibration signals for the online estimation of the state of rotating machinery using a modified extended Kalman filtering algorithm and spectral analysis in the time-frequency domain. Adaptability and spectral resolution capability of the model have been tested by using simulated vibration signal with abrupt changes and time-varying spectral content. The implementation of this model to detect machinery deterioration under varying operating conditions for condition-based maintenance purposes has been conducted by using real gearbox vibration monitoring signals. Experimental results demonstrate that the proposed model is able to quickly detect the actual state of the rotating machinery even under highly non-stationary conditions with abrupt changes and yield accurate spectral information for an early warning of incipient fault in rotating machinery diagnosis. This is achieved through combination with a change detection statistic in bi-spectral domain.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Bingley : Emerald
    Journal of quality in maintenance engineering 9 (2003), S. 223-238 
    ISSN: 1355-2511
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology , Economics
    Notes: Overall equipment effectiveness (OEE) is being used increasingly in industry. This paper defines OEE and explores the purpose of this concept in modern operations. The paper discusses OEE as a total measure of performance that relates the availability of the process to the productivity and quality of the product. Therefore, the concept of OEE is appropriate to all operations containing plant and machinery. Research has shown that the most successful method of employing OEE is to use cross-functional teams aimed at improving the competitiveness of business.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Engineering computations 21 (2004), S. 304-317 
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: In this paper, a 3D DEM program TRUBAL, which is capable of calculating the contact between particles considering friction and local plastic deformation, is employed to study the evolution of internal structure of particle assemblies during the consolidation process. Uniaxial powder compaction process is simulated in a cubic periodic unit cell by applying the strain rate to the individual particles. The selection of the proper time steps in DEM for quasi-static case is discussed. Results in particle scale (microscopic) are obtained and correlated to the statistical bulk response of the assembly. The effects of the microscopic properties of particles (such as friction, plastic contact) on the bulk mechanical response are examined by numerical tests. Correlations between the microscopic properties of particles and the macroscopic continuum behaviours of compacts are discussed. These discussions make it possible to fit DEM results at a macroscopic scale to the experimental measurements by adjusting the particle properties in DEM calculation. An example test is carried out to demonstrate that DEM results could be fitted properly to the experimental results, in the mean time, also provide some microscopic results which are hard to be measured. DEM has the potential to incorporate the microscopic properties of particles into a proper continuum model to perform combined macro and micro study of the powder compaction process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2004-04-01
    Print ISSN: 1366-9877
    Electronic ISSN: 1466-4461
    Topics: Technology
    Published by Taylor & Francis
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...