Fatigue of sandwich structures with inserts

The main purpose of the study was to evaluate fatigue in sandwich structures with inserts. Cross-linked PVC foam with closed cells as the core material was used in this investigation because this foam type has gained widespread use for maritime applications. Fatigue tests for a four-point bending test on a sandwich-beam containing an insert were investigated using numerical fatigue calculations in addition to the finite element method. A small crack initiated in the numerical model was propagated by reducing the stiffness of the finite elements at the crack tip. The J-integral was used when estimating the energy release rate. The stiffness of the insert material was used as a design parameter. It was seen from the investigation that the stiffness of the insert material had almost no influence on the fatigue crack propagation. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.