Impact behavior of thin thermoplastic composites dependant on manufacturing parameters and layup

The amount of structural application of carbon composites has grown massively in the last years. Carbon composites are known to provide superior performance with regard to their specific strength and stiffness. One of the major drawbacks, limiting the fields of application and defining knock down factors, is their sensitivity for impact damages. Thermoplastic resin systems are known to provide a better performance on impact behavior compared to thermoset resin systems. Within this paper, an investigation on the impact behavior of carbon composite plates with PEEK resin system is presented. The impact performance is derived by measurement of damage size, penetration depth and residual strength. For structural applications, composites provide the possibility to take use of tailored mechanical properties of laminates, like strength and stiffness by defining specific stacking sequences. Since the impact performance is also affected by the layup, different laminate configurations, starting from low in plane stiffness up to high stiffness, were investigated. Particularly for lightweight applications thin laminates are relevant. To provide the capability to determine the post impact compressive strength of thin plates, avoiding premature failure caused by buckling, a modified test bed for compression after impact test has been developed. Furthermore, within this work the influence of different manufacturing parameters on the impact performance and material properties was investigated, thus allowing an optimized manufacturing process with regard to cost and performance.