FATIGUE IN SANDWICH STRUCTURES LOADED IN TRANSVERSE-SHEAR

The main purpose has been to evaluate the fatigue properties for cross linked PVC foams with closed cells which are used extensively as core material in sandwich structures for marine applications. Different fat igue crack propagation criteria were investigated from four point bend ing fatigue tests on sandwich beams. This was done by placing a crack in the midplane of the beam in a Finite Element model, and determining the stress intensity factors for mode I and mode II, as the crack pro pagates. The criteria were: the maximum hoop stress criteria, the mini mum energy criteria and the maximum energy release rate criteria. As a result, the maximum hoop stress seems to be suitable for cross-linked PVC foams. (C) 1998 Published by Elsevier Science Ltd. All rights res erved.