Accession Number : AD0769867

Title :   High-Performance Composite Materials for Vehicle Construction: An Elastoplastic Analysis of Crack Propagation in a Unidirectional Composite,


Personal Author(s) : Adams,Donald F.

Report Date : MAR 1973

Pagination or Media Count : 106

Abstract : A method has been developed for predicting the strength of a unidirectional composite material in terms of its micromechanical response to an applied stress. It includes elastoplastic material behavior, local failure that initiates a crack, and propagation of the crack to cause total failure of the composite. A specific loading condition, transverse normal loading, has been selected for detailed analysis. It is often the transverse properties that limit the performance of the composite system. Therefore, this loading condition is of particular interest to composite materials technology because of the inherently low transverse strength of most high-performance composites. The basic principles of the theory of plasticity have been combined with a finite element numerical analysis technique. The result is a rigorous analysis procedure capable of accurately modeling the complex boundary-value problem being considered, an initial step toward the ultimate goal of accurately predicting the strength of a material. A complete digital computer program has been developed as part of the investigation, permitting the ready application of the analysis to practical engineering problems. Because the primary goal of the study was to develop a method of analysis and to write an associated computer program, only limited numerical results have been obtained to date. (Author, modified-PL)

Descriptors :   *Composite materials, Aircraft, Parallel orientation, Crack propagation, Numerical analysis, Airframes, Fibers, Stress strain relations, Failure

Subject Categories : Aircraft
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE