ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    facet.materialart.
    Unbekannt
    Dynamic moduli and localized damage in composites (1986)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The scatter of elastic waves due to a thin, flat ellipsoidal inhomogeneity, either penny shaped or elliptical is discussed. An average theorem appropriate for dynamic effective mass density and effective moduli was developed via a self-consistent scheme. Effective material properties of two-component media consisting of randomly distributed spheres are given here as a special case.
    Schlagwort(e): ACOUSTICS
    Materialart: NASA. Lewis Research Center Analytical Ultrasonics in Materials Research and Testing; p 233-256
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unbekannt
    Volume integrals associated with the inhomegeneous Helmholtz equation. Part 2: Cylindrical region; rectangular region (1983)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: Results are presented for volume integrals associated with the Helmholtz operator, nabla(2) + alpha(2), for the cases of a finite cylindrical region and a region of rectangular parallelepiped. By using appropriate Taylor series expansions and multinomial theorem, these volume integrals are obtained in series form for regions r r' and r 4', where r and r' are distances from the origin to the point of observation and source, respectively. When the wave number approaches zero, the results reduce directly to the potentials of variable densities.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3750 , NAS 1.26:3750
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unbekannt
    Volume integrals associated with the inhomogeneous Helmholtz equation. Part 1: Ellipsoidal region (1983)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: Problems of wave phenomena in fields of acoustics, electromagnetics and elasticity are often reduced to an integration of the inhomogeneous Helmholtz equation. Results are presented for volume integrals associated with the Helmholtz operator, nabla(2) to alpha(2), for the case of an ellipsoidal region. By using appropriate Taylor series expansions and multinomial theorem, these volume integrals are obtained in series form for regions r 4' and r r', where r and r' are distances from the origin to the point of observation and source, respectively. Derivatives of these integrals are easily evaluated. When the wave number approaches zero, the results reduce directly to the potentials of variable densities.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3749 , NAS 1.26:3749
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unbekannt
    Fundamentals of microcrack nucleation mechanics (1985)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: A foundation for ultrasonic evaluation of microcrack nucleation mechanics is identified in order to establish a basis for correlations between plane strain fracture toughness and ultrasonic factors through the interaction of elastic waves with material microstructures. Since microcracking is the origin of (brittle) fracture, it is appropriate to consider the role of stress waves in the dynamics of microcracking. Therefore, the following topics are discussed: (1) microstress distributions with typical microstructural defects located in the stress field; (2) elastic wave scattering from various idealized defects; and (3) dynamic effective-properties of media with randomly distributed inhomogeneities.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3851 , E-2296 , NAS 1.26:3851 , RFP763340/714952
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unbekannt
    Mechanics aspects of NDE by sound and ultrasound (1982)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: Nondestructive evaluation (NDE) is considered as a means to detect the energy release mechanism of defects and the interaction of microstructures within materials with sound waves and/or ultrasonic waves. Ultrasonic inspection involves the frequency range 20 kHz-1 GHz with amplitudes depending on the sensitivity of the test instrumentation. Pulse echo systems are most frequently used in NDE. Information is extracted from the signals through measurements of the signal velocity, attenuation, the acoustic emission when stress is applied, and calculation of the acoustoelastic coefficients. Fracture properties, tensile and shear strengths, the interlaminar shear strength, the cohesive strength, yield and impact strengths, the hardness, and the residual stress can be assayed by ultrasonic methods. Finally, attention is given to analytical treatment of the derived data, with mention given to transition matrix, integral equation, and eigenstrain approaches.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: Applied Mechanics Reviews; 35; Aug. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unbekannt
    Fundamental aspects in the quantitative ultrasonic determination of fracture toughness: General equations (1981)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The problem of establishing a theoretical groundwork for experimentally-found correlations between ultrasonic and fracture toughness factors in polycrystalline metals is discussed. It is noted that the link between these material properties and ultrasonic factors are the microstructural parameters that interact with stress wave propagation during deformation and fracture. The dynamic response of material inhomogeneities and the strains and displacements they undergo under incident stress waves are considered. Dynamic strains and displacements inside and outside scatterers are treated. The underlying approach, the formulation and governing equations for the eigenstrains, and the determination of the energy due to the presence of inhomogeneities are presented. The stress wave interaction problem is presented in terms of the dynamic eigenstrain concept.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3445
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unbekannt
    On the feasibility of quantitative ultrasonic determination of fracture toughness: A literature review (1980)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The three main topics covered are: (1) fracture toughness and microstructure, (2) quantitative ultrasonic and microstructure; and (3) scattering and related mathematical methods. Literature in these areas is reviewed to give insight to the search of a theoretical foundation for quantitative ultrasonic measurement of fracture toughness. The literature review shows that fracture toughness is inherently related to the microstructure and in particular, it depends upon the spacing of inclusions or second particles and the aspect ratio of second phase particles. There are indications that ultrasonic velocity attenuation measurements can be used to determine fracture toughness. The leads to a review of the mathematical models available in solving boundary value problems related to microstructural factors that govern facture toughness and wave motion. A framework towards the theoretical study for the quantitative determination of fracture toughness is described and suggestions for future research are proposed.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3356 , E-547
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unbekannt
    Ultrasonic wave propagation in two-phase media: Spherical inclusions (1983)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The scattering theory, recently developed via the extended method of equivalent inclusion, is used to study the propagation of time-harmonic waves in two-phase media of elastic matrix with randomly distributed elastic spherical inclusion materials. The elastic moduli and mass density of the composite medium are determined as functions of frequencies when given properties and concentration of the spheres and the matrix. Velocity and attenuation of ultrasonic waves in two-phase media are determined for cases of distributed spheres and localized damage. An averaging theorem that requires the equivalence of the strain energy and the kinetic energy between the effective medium and the original matrix with spherical inhomogeneities is employed to derive the effective moduli and mass density. The functional dependency of these quantities upon frequencies and concentration provides a method of data analysis in ultrasonic evaluation of material properties. Numerical results or moduli, velocity and/or attenuation as functions of concentration of inclusion material, or porosity, are graphically displayed.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3732 , NAS 1.26:3732
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unbekannt
    Scatter of elastic waves by a thin flat elliptical inhomogeneity (1983)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: Elastodynamic fields of a single, flat, elliptical inhomogeneity embedded in an infinite elastic medium subjected to plane time harmonic waves are studied. Scattered displacement amplitudes and stress intensities are obtained in series form for an incident wave in an arbitrary direction. The cases of a penny shaped crack and an elliptical crack are given as examples. The analysis is valid for alpha a up to about two, where alpha is longitudinal wave number and a is a typical geometric parameter.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3705 , NAS 1.26:3705
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unbekannt
    The transmission or scattering of elastic waves by an inhomogeneity of simple geometry: A comparison of theories (1983)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The extended method of equivalent inclusions is applied to study the specific wave problems: (1) the transmission of elastic waves in an infinite medium containing a layer of inhomogeneity, and (2) the scattering of elastic waves in an infinite medium containing a perfect spherical inhomogeneity. Eigenstrains are expanded as a geometric series and a method of integration based on the inhomogeneous Helmholtz operator is adopted. This study compares results, obtained by using limited number of terms in the eigenstrain expansion, with exact solutions for the layer problem and that for a perfect sphere.
    Schlagwort(e): QUALITY ASSURANCE AND RELIABILITY
    Materialart: NASA-CR-3659 , E-1394 , NAS 1.26:3659 , RF-TECH-104
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...