Experimental Investigation of Compression Failure Mechanisms of Composite Faced Foam Core Sandwich Specimens

Compression failure of sandwich specimens with glass/vinylester face sheets over PVC foams has been experimentally examined using an end loading test fixture based on the ASTM C 364 standard. The main objective of the research was to examine the roles of the faces and core in the mechanism of failure and ultimate load carrying ability of the structure. A range of PVC foam densities, core thicknesses, and specimen lengths were examined. Failure modes were identified, and compression strengths were compared to analytical predictions. Short specimens failed by compression failure of the face sheets up to a gage length that increased with increased foam density, and decreasing core thickness. At intermediate gage lengths it was found that specimens with a thick low density core failed in an anti-symmetric face wrinkling mode, while long specimens failed by global buckling in the fundamental buckling mode. Predictions of the failure loads were found to be in reasonable agreement with experimental results.