Theoretical and Experimental Investigation of Failure and Damage Progression of Graphite-Epoxy Composites in Flexural Bending Test

Abstract

Predicting failure stress and failure modes in composite laminates is very difficult. The choice between failure criteria is complex and there is a lack of experimental study to validate the results obtained. In this paper, a theoretical and experimental study of damage progression and failure modes of graphite-epoxy laminates in three points bending tests is presented. A quasi-isotropic [(± 45/9010)]5 graphite-epoxy composite is investigated. C-scan method and microscopic sectioning permit to monitor damage progression and failure modes during the experiment. Specimens at different failure levels are used to determine damage progression and the effect of geometrical parameters on the successive failures and on failure modes is studied. The progression of damage has been followed experimentally and identified in detail. The theoretical study is based on the classical laminate theory in the case of in-plane loads. A software program has been elaborated for post-failure treatment and experimental results are compared with numerical predictions.