Accession Number : ADP001921

Title :   Computation of Influence of Defects on Static and Fatigue Strength of Composites,


Personal Author(s) : Tennyson,R. C. ; Hansen,J. S. ; Heppler,G. R. ; Mabson,G. ; Wharram,G.

Report Date : JUL 1983

Pagination or Media Count : 17

Abstract : A combined analytical and experimental investigation has been undertaken to determine the effects of flaws on the static strength and fatigue life of graphite/epoxy (ASI/3501-6) laminates. Both bond-line defects in sandwich beam construction and interlaminar disbond flaws were studied. Up to present, compressive strength test data have been obtained for ambient and elevated temperature, moisture-saturated conditions, including results from thermal-spike cycling simulating supersonic flight. In addition, baseline data have been obtained to define the strength parameters associated with the tensor polynomial lamina failure criterion. Although this model was originally derived for static 'unflawed' strength predictions, it is being extended to include the effect of holes and flaws. In the latter case, a finite element approach is described to illustrate the methodology for computing the influence of flaws. Finally, a formulation for predicting the fatigue life of laminates is presented based on the experimental evaluation of fatigue functions which are utilized in a form of the tensor polynomial failure criterion.

Descriptors :   *Composite materials, *Defects(Materials), *Structural mechanics, Epoxy laminates, Graphite, Strength(Mechanics), Fatigue tests(Mechanics), Static tests, Composite structures

Distribution Statement : APPROVED FOR PUBLIC RELEASE