Accession Number : AD0783228

Title :   Influence of Cycle Frequency on Composite Fatigue Reliability,

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG COLL OF ENGINEERING

Personal Author(s) : Reifsnider,Kenneth L. ; Stinchcomb,W. W. ; Williams,Richard S. ; Turgay,H. M.

Report Date : APR 1974

Pagination or Media Count : 33

Abstract : Variations in the degradation and subsequent fatigue reliability of laminated composite plate specimens with a center hole due to changes in cycle frequency have been identified and investigated. Boron-epoxy and born-aluminum specimens were examined, principally for stiffness and strength variations. Various combinations of stiffness and strength changes were observed as a function of cycle frequency and specimen material, including a mode wherein stiffness decreased significantly while residual strength increased. A kinetic damage model was developed and combined with a Weibull extreme value expression to attempt to represent the stochastic aspects of the fatigue process. The model shows considerable promise, especially from the standpoint of representing widely varying fatigue behavior, including the unusual stiffness drop with strength increase situation. Frequency dependence is included in the model. (Author)

Descriptors :   *Composite materials, *Fatigue(Mechanics), Boron, Epoxy resins, Aluminum, Laminates, Reliability

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE