Hole-wall temperature characteristics in thick UD-CFRP drilling by different condition

Due to the low thermal conductivity of CFRP and serious axial heat accumulation in dry drilling condition, the excessive cutting temperature simulation and suppression analysis have been the main research fields to analyze and improve borehole quality with the wide application of thick CFRP component in main load-carrying structures of aircraft. This paper proposed a three-dimensional drilling temperature simulation model to investigate the complex cutting temperature characteristics and predict the overheating area distribution during thick UD-CFRP drilling with dry condition and Boelube lubricant, thereby revealing its effects on occurrence of thermal-mechanical damages. Different from the previous drilling temperature simulation models, the material continuous removal process in this model was considered and discretized into finite chip layers removal process to model its effects on drilling heat transfer. Based on thermography method, a drilling temperature measurement experiment was conducted to validate the simulation model. Meanwhile, the overheating area distribution was predicted and the obvious reduction effects of ECL method on the overheating area ranges were confirmed. Moreover, the size of overheating area was proved to be a qualitative index of whether the hole wall subsurface damage at against fiber cutting zone is serious or not.