Reduction of slamming damage in the hull of high-speed crafts manufactured from composite materials using viscoelastic layers

Resumen

Pre-impregnated Out-of-Autoclave cured Glass Fiber Reinforced Polymer panels are more and more often used because they offer many advantages compared to other traditional materials for marine applications. For high-speed crafts, the shift to new materials was initially driven by a need to obtain lighter, stronger vessels that would withstand corrosion and environmental agents (e.g., temperature, humidity, and chlorides) with the capacity to manufacture structures with complex geometries and with the possibility of adapting the mechanical properties of the material according to the needs of the design, high strength-to-weight ratio, ease of repair and robust durability. A new experimental set-up has been designed to reproduce the slamming impacts in small samples of the material, at different velocities and impact energies. Ultrasonic C-scan inspection of each of the prepared specimens has been conducted to evaluate its quality level and the absence of porosity zones. After a certain number of cycles of impacts, each panel was removed and inspected again to assess damage evolution, and the micromechanisms of interlaminar and intralaminar damage propagation have been observed with scanning electron microscopy. Damage levels have been correlated to residual strengths using AITM-0010 test method for determination of compression strength after impact. It is shown how is possible to effectively mitigate the damage by slamming by inserting a viscoelastic layer into the GFRP panels. The structured combination of a polymer with high deformation capacity with domains of a second, rigid polymer, dampens the impacts and delays the damage progresion, improving the dissipation of impact energy, thus protecting the structure of the hull and increasing the service life of the high-speed crafts.