Accession Number : ADA322238

Title :   Evolution and Stability of a Crack with a Process Zone. Experimental and Theoretical Studies. Two Parameter Crack Layer Model: Equilibrium, Evolution, Stability. Aging Phenomena and the Intrinsic Material Geometry.

Descriptive Note : Final rept. 30 Jul 95-30 Jul 96,

Corporate Author : ILLINOIS UNIV AT CHICAGO CIRCLE

Personal Author(s) : Chudnovsky, A. ; Shulkin, Y. ; Preston, S.

PDF Url : ADA322238

Report Date : 30 SEP 1996

Pagination or Media Count : 121

Abstract : The report contains two parts: (1) Two parameter crack layer model and (2) Aging phenomena and the intrinsic material geometry. In the first part, the crack layer model is substantiated from the thermodynamic standpoint, the kinetic equations governing crack layer evolution are derived, and stability of the crack layer stationary state and propagation is analyzed. The proposed model is examined for the engineering thermoplastics studied in detail experimentally. In the second part, a variational approach to the derivation of constitutive equations of material aging is proposed. Elastic properties and irreversible deformations are represented by a 4D material metric tensor. Equations governing evolution of the tensor are obtained and studied. The theory is illustrated by examples.

Descriptors :   *AGING(MATERIALS), *CRACK PROPAGATION, STRESS STRAIN RELATIONS, LOAD DISTRIBUTION, LIFE EXPECTANCY(SERVICE LIFE), FATIGUE LIFE, DEFORMATION, ELASTIC PROPERTIES, THERMAL STABILITY, FRACTURE(MECHANICS), THERMOPLASTIC RESINS, FORCE(MECHANICS), VARIATIONAL PRINCIPLES.

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE