Accession Number : AD0760438

Title :   Acceleration Waves in Simple Elastic Materials,

Corporate Author : BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s) : Wright,T. W.

Report Date : MAR 1973

Pagination or Media Count : 84

Abstract : The classical method of characteristic surfaces and bicharacteristic rays is used to study acceleration and higher order discontinuities in nonlinear simple elastic materials. No special material symmetry is assumed, and the analysis requires neither material homogeneity nor uniform conditions ahead of the wave in general, although many detailed results do require the latter two conditions. This paper draws heavily on known results, but at the same time many other results, believed to be new, have been included. Analysis of the motion of the singular surface precedes a discussion of the amplitude equations. It is shown that the Jacobian determinant of a certain coordinate transformation induced by the motion of the surface, plays a dominant role in the equations for transport of amplitude. New results on the kinematics of singular surfaces are given for homogeneous and uniform materials, including a formula for the evolution of surface curvature in anisotropic materials, and a complete description of the role of the curvatures of the initial singular surface and of the characteristic slowness surface in producing expansion or focusing of the singular surface. (Modified author abstract)

Descriptors :   (*MECHANICAL WAVES, KINEMATICS), PROPAGATION, STRAIN(MECHANICS), ELASTIC PROPERTIES, CURVED PROFILES, ANISOTROPY, MATHEMATICAL MODELS, EQUATIONS OF MOTION, NONLINEAR SYSTEMS

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE