Impact of a tri-dimensional conical structure made of composite materials

This paper investigates the impact strength of a three-dimensional conical structure constructed from composite materials, focusing on its application in wave energy converters. Two glass fibre-reinforced polymers, unidirectional and bi-axial stitched fabrics, are analysed. The study includes an experimental low-velocity impact of plates with solid objects, simulating low-velocity impact with floating debris, and an experimental bottom wave slamming test where the structure is dropped from a height of 1.5 m onto a calm water surface equivalent to an initial velocity of 5.43 (m/s). In addition, a destructive buckling test is carried out by applying pressure to the conical to assess the buckling strength of both laminates. Furthermore, the experimental buckling pressure failure is compared with the pressure peak determined by a numerical simulation, based on the Arbitrary Lagrangian Eulerian formulation, and with a design pressure suggested by a classification society recommended practice. Results demonstrate that the biaxial stitched fabric reveals a higher impact strength on both impacts with solids and fluids and a higher buckling strength. Moreover, the peak pressure determined by the numerical simulation is slightly higher than that a conservative design approach predicted.