Accession Number : ADA332773

Title :   DAA-Based Computational Boundaries for Ground-Shock Analysis, Volume 1: DAA Formulation and Canonical Comparisons.

Descriptive Note : Technical rept. 1 May 92-30 Apr 95,

Corporate Author : COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Lewis, Brett A. ; Geers, Thomas L.

PDF Url : ADA332773

Report Date : 01 DEC 1997

Pagination or Media Count : 90

Abstract : This document describes the formulation and implementation of a computational boundary for elastic solids based on doubly asymptotic approximations (DAA's). DAA's combine high-frequency (wave propagation) and low-frequency (quasi-static) approximations in a systematic manner to produce a relationship between scattered-wave tractions and displacements on the boundary; this relationship approaches exactness at high and low frequencies and provides a smooth transition between. Second-order DAA's for three-dimensional, linear-elastic infinite and semi-infinite media are developed for implementation into general purpose numerical (finite element or finite difference) programs. In addition, modal DAA's for spherical cavities are developed. Then, DAA results, both general and modal, are compared with analytical and other numerical results for problems involving infinite and semi-infinite media.

Descriptors :   *NUMERICAL ANALYSIS, *GROUND SHOCK, FINITE ELEMENT ANALYSIS, ELASTIC PROPERTIES, BOUNDARIES, FINITE DIFFERENCE THEORY, APPROXIMATION(MATHEMATICS), ASYMPTOTIC SERIES.

Subject Categories : Numerical Mathematics
      Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE