Determination of compressive strength of unidirectional composites by three-point bending tests

A simple way for obtaining compressive strength of unidirectional composites by three-point bending tests is proposed in the present work. The interpretation of test results includes the stress singularity induced by the applied concentrated load and the determination of the contact zone between loading roller and specimen. Unidirectional carbon/epoxy composite T6T/F593 from Hexcel Composites has been tested by three-point bending with different thicknesses and spans. When failure occurs by compressive stresses, experimental results agree with the strength obtained by compressive tests. The best agreement is obtained in the case of 7 mm nominal thickness and span of 120 mm.