GFRP sandwich composites: calibration of a numerical model by large scale tests

Finite element modelling of structures is nowadays a widely used structural calculation technique, even in the design of pleasure craft built in composite materials. Design of such complex structures may need a reliable and quite precise numerical model. Therefore, calibration of the model with experimental results is enviable. The application to hull shell of a composite sandwich, having pre-preg epoxy skins and core made of syntactic epoxy foam, has been studied in the framework of a wider research programme. Large scale three point bending tests of panels of such sandwich have been carried out in the DINAV Ship Structures laboratory and have been completed by small scale tests. In addition to load and deflection of the panels, gages measured the strains on the outer sides of skins and also between the foam core and the skins. Besides the traditional gages, innovative wire sensors, conceived by the DINAV laboratory, have been enclosed between the core and the skins during the lamination. Afterwards, experimental data have been compared with finite element models developed in the ANSYS® environment, aiming at calibrating numerical models.