Investigation on the mechanical robustness of CFRP molds

Molds made from carbon fiber reinforced plastics (CFRP) have advantages over metallic molds as equal thermal expansion and lower costs. On the other hand these molds have a limited service time for example due to surface wear out. To extend the service times of these molds concepts that reinforce or protect exposed areas in the tool as for example edges need to be developed. The aim of this work is to investigate the parameters that influence the failure of composite edges due to a static load. Therefore a test has been developed that determines a quasi-static strength of edges. Based on this test the mechanical properties of composite edges with different fiber reinforcements and matrix systems are compared. The edge concepts investigated are: an edge filled with the conventional laminate resin, one with a gelcoat reinforced surface, a reinforcement by a roving along the edge, a short fiber reinforcement and an edge with a locally applied elastomeric matrix system. The test show that fiber reinforcements in the edge lead to a higher edge stiffness and strength. The deviation of the results strongly dependent on the distribution of the reinforcing fibers in the edge. Elastomeric edges are a promising concept since no damage occurs at all within the test.