Showing papers by "Ajit Mal published in 1974"
TL;DR: In this article, the authors studied the propagation of time-harmonic elastic waves in a fiber-reinforced composite, where the circular fibers were assumed to be parallel to each other and randomly distributed with a statistically uniform distribution.
Abstract: T he propagation of time-harmonic elastic waves in a fiber-reinforced composite is studied. The circular fibers are assumed to be parallel to each other and randomly distributed with a statistically uniform distribution. The direction of propagation and the associated particle motion are considered to be normal to the fibers. It is shown that the average waves in the composite separate into compressional and shear types. General formulae for the complex wave number giving the phase velocity and the damping are obtained. It is shown that these formulae lead to the Hashin-Rosen expressions for the transverse bulk modulus and the lower bound for the transverse rigidity, if the correlation in the positions of the fibers can be ignored. The correlation terms, for exponential correlation, are shown to have a significant effect on the damping property of the composite, especially at high frequencies and concentrations.
114 citations
01 Nov 1974
TL;DR: In this paper, an isotropic elastic material containing a random distribution of identical spherical particles of another elastic material is considered, where the bonding between the spheres and the matrix is imperfect, so that slip may occur at interfaces when stress is applied to the medium.
Abstract: An isotropic elastic material containing a random distribution of identical spherical particles of another elastic material is considered. The bonding between the spheres and the matrix is imperfect, so that slip may occur at interfaces when stress is applied to the medium. The shear stresses at the interface is assumed to be proportional to the amount of slip. The velocity and attenuation of the average harmonic elastic waves propagating through such a medium are calculated. The results are valid to the lowest order in frequency for wave lengths long compared with the radius of the sphere. The dynamic elastic moduli are obtained from these results and are compared with available results for welded contact. The variations in the P and S wave velocities for propagation across earthquake faults is discussed.
105 citations
TL;DR: In this paper, the propagation of coherent elastic shear waves in a medium containing a dilute and uniform distribution of cylindrical inclusions is discussed, where the waves are assumed to be polarized parallel to the axes of the cylinders while the cylinders are thin compared to the wavelength.
Abstract: The propagation of coherent elastic shear waves in a medium containing a dilute and uniform distribution of cylindrical inclusions is discussed. The waves are assumed to be polarized parallel to the axes of the cylinders while the cylinders are assumed to be thin compared to the wavelength. The complex wavenumber is calculated to a second order of approximation, the real part of which gives the propagation speed and the imaginary part gives the damping due to scattering. Numerical results are obtained for the case of identical inclusions with the properties of the inclusions varying between hollow (void) and rigid.
24 citations