Indentation and penetration of carbon fibre reinforced plastic laminates

Static tests were carried out on circular carbon fibre reinforced plastic plates of various thicknesses, which where loaded at the center by a hemispherical steel indentor. The tests were stopped at predetermined values of the displacement, and the indentation after the loading stage was evaluated. Tests were also performed up to complete penetration, using different indentor diameters. The data generated were compared with similar results previously obtained under low-velocity impact conditions, and treated according to models developed for the dynamic case. Apparently, both the penetration energy and indentation were not affected by the loading speed. The new experimental results showed that an empirical law previously proposed by the authors, aiming to predict the indentation as a function of the absorbed energy, is inaccurate when high energy levels are imparted to the material. A new empirical law, more efficient than the earlier, was assessed. The data collected indicate that the constants appearing in the new model are negligibly influenced by the laminate type and thickness, and constraint conditions adopted.