Collapse of FRP/syntactic foam sandwich panels

In the framework of a wider research project, large scale testing of composite sandwich panels has been carried out at the DINAV shipbuilding laboratory. The skins of the sandwich are made of fibre glass epoxy prepreg and the core consists of a syntactic epoxy foam. Strain gages have been bonded on the outer skins and also located in between the core and the skins. The captioned material is currently used for small components of naval ships (e.g. shields, stanchions, etc.) either in single skin laminates and sandwich: the final goal of the project is to study its applicability in building pleasure craft hulls, taking advantage of its high strength. The large scale tests have been completed by usual testing on small scale specimens, according to well-known international standards and analytical and finite elements (FE) numerical models have been calibrated with the experimental data. Different options of FE codes have been investigated in order to catch their capabilities and approximations in modelling the composite material and their damage up to collapse. Some advices of the behaviour of quite large sandwich panels are reported, highlighting the effects of the size of the structure on the material mechanical properties.