Accession Number:

ADA250785

Title:

Instabilities of Damage and Surface Degradation Mechanisms in Brittle Material Structural Systems

Descriptive Note:

Final rept. 1 Jul 1989-31 Dec 1991

Corporate Author:

ARIZONA UNIV TUCSON ENGINEERING EXPERIMENT STATION

Report Date:

1992-03-15

Pagination or Media Count:

315.0

Abstract:

A review of the theoretical and experimental information on surface degradation and related instabilities is presented, and the physical significance of surface or skin effects is identified. The research involves study of relation between surface degradation and scale or size as well as shape effects, and surface damage growth instabilities and related bursting in brittle materials. A theory is developed to trace growth of surface degradation and to- identify onset of relevant instabilities. Here internal length is also estimated based on available experimental results. A comprehensive series of laboratory compression tests are performed on rectangular specimens with different dimensions of an artificial rock like material. Simultaneous nondestructive ultrasonic measurements are obtained at various locations on the -specimens. The damage and instability distributions obtained by using a finite element procedure and symbolic computation are related to the dissipated energy derived from ultrasonic measurements. Comparisons of theoretical predictions and nondestructive measurements correlate very well. Surface effects, Degradation, Energy dissipation, Brittle materials, Experiments, Numerical predictions, Verification.

Subject Categories:

  • Numerical Mathematics
  • Test Facilities, Equipment and Methods
  • Mechanics
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE