Equivalent Material Identification in Composite Scaled Hulls Vertical Impact Tests

The impact in water is a very complicated phenomenon due to the interaction between the hydrodynamic field and the structures and the possibility to investigate its characteristics by means of a scaled model seems straightforward. In general, the similarity procedure requires the scaling of different properties (mass, length, speed, etc.) to properly represent such a phenomenon. In the present case the fluid-dynamic phenomena are scaled thanks to the Froude similarity while the definition of specific material and its scaling rules for a complete similarity is required in several cases particularly when composites play a predominant role on the test response. The introduction of Trace parameter is proposed as a method orienting the designer for the right material selection in these situations. Numerical simulation using the LS-DYNA software and modified Von Karman theory is used to validate the procedure in predicting the maximum pressure in the first phases of impact. An experimental test is finally designed to calibrate the physical and numerical parameters