Accession Number:

ADA247300

Title:

Plane Wave Propagation in Random Granular Media

Descriptive Note:

Final rept.

Corporate Author:

PURDUE UNIV LAFAYETTE IN

Personal Author(s):

Report Date:

1992-02-01

Pagination or Media Count:

47.0

Abstract:

A Markov property of disturbance propagation forms the basis for a study of wavefronts in graph representable microstructures. Stochastic Huygens minor principle is developed to analyze wavefront propagation in 1-D, 2-D, and 3-D models of material microstructures. A diffusion approximation is obtained for microstructures with grains described by piecewise linear constitutive laws. A new general method of solution to transient wave problems in such microstructures is developed. The method uses solutions from deterministic problems as a reference basis for an analysis of field fluctuations and scatter in stochastic media. The wavefront is modeled as a random field in space-time governed by a Markovian propagator. Explicit formulas for random arrivals in space-time and random modulation of pulses are obtained from this diffusion approximation. The key coefficients appearing in these formulas are calculated in the dimensionless setting of a 1-D linear elastic setting for a wide range of statistics of material properties. Finally, a local averaging process is proposed to obtain various smoothing approximations of this random field.

Subject Categories:

  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE