Failure behaviour of foam-based sandwich joints under pull-out testing

Sandwich materials have been used widely in various fields. However, the failure behaviour of the joints that connect the sandwich structures is not fully understood. In this paper, foam-based sandwich joints were studied under pull-out conditions through experiments and numerical analyses. Two different types of joints, with and without inserts, were examined. The experiments showed that the failure modes of sandwich joints were a combination of different failure modes, such as core shear failure, the debonding of face and potting material, composite face failure, and local failure. A finite element analysis using MSC.MARC was also conducted to predict the failure load of sandwich joints. Two methods were applied to predict the first drop of the sandwich joints: progressive failure analysis and the damage zone method. The former resulted in an acceptable prediction for a preliminary design, and the latter was shown to predict the first peak of loading curves very well.