Buckling behavior of FRP sandwich panels made by hand layupand vacuum bag infusion procedure

This paper deals with strength of composite sandwich panels typically used in pleasure boats and naval industry. The focus is on the influence of fabrication processes onto the mechanical behavior, namely onto buckling strength. Both, experimental and numerical analyses were carried out in the Ship Structures Laboratory of the University of Genova on rectangular specimens, whose dimensions and geometry were conceived to induce buckling collapse, being this one a typical failure mode under compressive loading for thin skins sandwich. Tests on both hand layup fabricated and infusion made panels were carried out measuring compressive load vs. shortening and lateral deflection. Videos of the tests were taken and used to gather some measurements and to assess failure time and location. Experimental results were compared with different numerical models, developed considering large deformations in the PVC core under buckling conditions. Various finite element types and different implementation were considered to model complex interactions between core and skins. The conclusions of this paper aim to provide designers of pleasure and naval crafts with some hints about different strategies to build up costeffective numerical models for predicting buckling and post-buckling behavior of sandwich hulls, taking advantage of calibrations obtained through experimental testing.