Previous studies have often assumed that the mechanical properties of Carbon Fibre Reinforced Plastics (CFRP) remain unchanged during drilling. In fact, due to the increase in drilling temperature, the mechanical properties of the composites change greatly, and this then affects the critical force. In addition, previous studies have often assumed that the failure mode of CFRP drilling was a type I crack failure. In fact, due to the complexity of the CFRP drilling process, the failure modes are often coupled with different failure modes, so type I cracks alone cannot reflect the actual cracking situation. Therefore, a three-dimensional drilling Finite Element Modeling (FEM) was established to analyze the failure modes of CFRP drilling delamination, and the I/III mode was determined; then, a new drilling critical force mechanics model, which considers the temperature dependence of CFRP mechanical properties and the failure modes of CFRP drilling delamination, was established based on the classical drilling critical force mechanics model; the results of the mechanics model were validated by drilling critical force experiments under different temperatures. The effects of the temperature dependence of CFRP mechanical properties on the drilling critical force were investigated and analyzed.
Keywords: CFRP drilling; critical force; drilling delamination damage; temperature-dependent characteristics of CFRP mechanical properties.