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71.
The paper presents a numerical study of the propagation of plane waves in a half-space occupied by a granular material, with periodic boundary conditions for velocity or stresses prescribed at the boundary of the half-space. The constitutive behaviour of the material is described by a simplified hypoplastic equation which takes into account different values of the stiffness for different directions of deformation, and the coupling between shear and volumetric strains owing to dilatancy. These two features are responsible for a nonlinear character of longitudinal waves and for the generation of longitudinal motion by transverse disturbances. It is shown that longitudinal and transverse boundary disturbances produce qualitatively the same longitudinal waves at large distances from the boundary. As a longitudinal wave propagates, the amplitude of oscillations decreases and eventually vanishes, resulting in a single non-oscillating wave.Received: 10 September 2002, Accepted: 31 March 2003
Correspondence to: Y. A. Berezin 相似文献
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Herbert Hutter Peter Wilhartitz Manfred Grasserbauer 《Fresenius' Journal of Analytical Chemistry》1993,346(1-3):66-68
Summary The potential of 3D-SIMS for characterization of high molybdenum powder and sintered high purity molybdenum will be demonstrated. The concentration of the measured trace elements in the sintered molybdenum did not exceed 200 ppb. In the powder the concentration was found to be about 1 ppm. For material scientists it is very important to ascertain if the trace elements are homogeneously distributed or precipitated. Although the concentration of the elements of interest was rather low, qualitative images of the three dimensional distribution can be obtained. 相似文献
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Luca Placidi Kolumban Hutter 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2005,14(8):160-181
New and explicit anisotropic constitutive equations between the stretching and deviatoric stress tensors for the two- and
three-dimensional cases of incompressible polycrystalline materials are presented. The anisotropy is assumed to be driven
by an Orientation Distribution Function (ODF). The polycrystal is composed of transversally isotropic crystallites, the lattice
orientation of which can be characterized by a single unit vector. The proposed constitutive equations are valid for any frame
of reference and for every state of deformation. The basic assumption of this method is that the principle directions of the
stretching and of the stress deviator are the same in the isotropic as well as in the anisotropic case. This means that the
proposed constitutive laws are able to model the effects of anisotropy only via a change of the fluidity due to a change of
the ODF. Such an assumption is justified to guarantee that, besides knowledge of the parameters involved in the isotropic
constitutive equation, the anisotropic material response is completely characterized by only one additional parameter, a type
of enhancement factor. Explicit comparisons with experimental data are conducted for Ih–ice. 相似文献
78.
Holzweber M Kriegl M Schintlmeister A Paesold D Danninger H Hutter H 《Analytical and bioanalytical chemistry》2011,400(3):659-663
A study of grain boundary diffusion of oxygen in hot-rolled steel sheets is carried out by means of time-of-flight secondary-ion-mass-spectrometry
(ToF-SIMS). This involves polishing of the sample surface prior to the oxygen exposure. A nickel layer deposited after exposure
ensures a homogeneous extraction field for ToF-SIMS measurements at the Ni–steel interface. The sample is bevelled at an angle
of 11.5° to spread up the diffusion pathway by a factor of 5. The oxygen distribution is then acquired via ToF-SIMS in imaging
mode from which diffusion parameters are calculated according to the Whipple–Le Claire’s approach. 相似文献
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80.
Luca Placidi Kolumban Hutter 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2005,57(1):160-181
New and explicit anisotropic constitutive equations between the stretching and deviatoric stress tensors for the two- and
three-dimensional cases of incompressible polycrystalline materials are presented. The anisotropy is assumed to be driven
by an Orientation Distribution Function (ODF). The polycrystal is composed of transversally isotropic crystallites, the lattice
orientation of which can be characterized by a single unit vector. The proposed constitutive equations are valid for any frame
of reference and for every state of deformation. The basic assumption of this method is that the principle directions of the
stretching and of the stress deviator are the same in the isotropic as well as in the anisotropic case. This means that the
proposed constitutive laws are able to model the effects of anisotropy only via a change of the fluidity due to a change of
the ODF. Such an assumption is justified to guarantee that, besides knowledge of the parameters involved in the isotropic
constitutive equation, the anisotropic material response is completely characterized by only one additional parameter, a type
of enhancement factor. Explicit comparisons with experimental data are conducted for Ih–ice.
Dedicated to Prof. L.W. Morland on the occasion of his 70th birthday
Received: July 6, 2004; revised: November 8, 2004 相似文献