Accession Number : ADA305872

Title :   Exploratory Development of Fracture Mechanics of Composite Systems. Part 3.

Descriptive Note : Technical rept.,

Corporate Author : LEHIGH UNIV BETHLEHEM PA INST OF FRACTURE AND SOLID MECHANICS

Personal Author(s) : Sih, G. C. ; Hilton, P. D. ; Badaliance, R. ; Villarreal, G.

PDF Url : ADA305872

Report Date : JAN 1973

Pagination or Media Count : 166

Abstract : Analyses for laminar plates are reviewed in this report. It is observed that while approximate global stress analyses have been performed for laminates, little has been accomplished in the area of strength analysis. The work presented here is concentrated in that area, i.e., mathematical models to consider the influence of flaws on failure loads associated with crack propagation and/or delamination. In particular, an approximate three dimensional formulation for laminates based on the variational principle of minimum complementary potential energy is presented and applied to the problem of a three layer composite plate containing a through crack. This model is employed to study the influences of the geometric and material characteristics of the composite on the local stress field in the vicinity of the flaw. Results of an experimental program to determine the influence of plate thickness on critical load for a centrally cracked tensile specimen are reported. Extension of the experimental program to consideration of laminated specimens is currently in progress. A stress analysis has been carried out for another problem of particular interest in the study of failure for composite systems. The effect of voids in adhesive layers on the behavior of multilayer fibrous composites is modeled by the problem of a penny shaped flaw contained in an isotropic layer joining two orthotropic half spaces. Stresses in the vicinity of the crack edge are calculated in terms of the loading and the properties of the components for this composite system.

Descriptors :   *COMPOSITE MATERIALS, *FRACTURE(MECHANICS), *CRACK PROPAGATION, MATHEMATICAL MODELS, THICKNESS, STRESS ANALYSIS, LAMINATES, LOADS(FORCES), CRACKS, FORMULATIONS, ADHESION, COMPOSITE STRUCTURES, STRENGTH(MECHANICS), THREE DIMENSIONAL, GEOMETRIC FORMS, PLATES, POTENTIAL ENERGY, FAILURE(MECHANICS), VARIATIONAL PRINCIPLES.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE