Research on prediction method of mechanical properties of open-hole laminated plain woven CFRP composites considering drilling-induced delamination damage

Carbon fiber reinforced polymer (CFRP) is widely used in machinery and construction due to their extra-ordinary mechanical properties. Up to now, conventional drilling is the most common machining process to facilitate holes on CFRP laminates for the component assembly. However, drilling-induced delamination is widely considered as the most undesirable damage and challenging failure mode in this process. The present paper aims to propose a convenient and quick method to predict the mechanical properties of open-hole laminated plain woven CFRP composites more accurately. First, the delamination results of nondestructive test by C-scan and simulation were compared after practical experiment and numerical simulation of drilling process. Second, an equivalent parameter was proposed to simplify the delamination regions with complex boundaries, and the mechanical property evaluation model was constructed by introducing the initial delamination damage area, which was obtained from the drilling numerical simulation results. Finally, the effectiveness of the proposed method was demonstrated by analyzing the mechanical properties and failure modes of CFRP with processing delamination damage under loading conditions of tension, compression and bending. Therefore, the proposed method in this paper can help understand the degradation mechanism of composites after drilling and provide guidance for the design of open-hole laminated plain woven CFRP composites.