Analysis of Burr and Tear in Milling of Carbon Fiber Reinforced Plastic (CFRP) Using Finite Element Method

Carbon fiber reinforced plastics (CFRPs) are vulnerable to the intralaminar damage (including burr and tear) and interlaminar damage (including delamination) during milling process. These damages will decrease the load carrying capability of the components. However, due to the different formation conditions and occurrence locations of the two types of damages, it is a challenge to accurately simulate them in a single model, which hinders the comprehensive understanding on the formation laws of CFRP milling damages. The present study establishes a novel three-dimensional macroscopic milling model, which predicts both the interlaminar fracture and intralaminar cracking of the CFRP. The cohesive elements are applied to model the interlaminar fracture. The intralaminar cracking is also simulated by inserting cohesive elements in the top layer of CFRP along the fiber direction, and the insert interval is adjusted for an enhanced accuracy of the model. Furthermore, a Python script is defined to improve the efficiency of establishing the model. Through the calculation of the models, the cutting forces and the damage extents at four typical fiber orientation angles (FOAs) are both accurately calculated. Moreover, the formation laws of CFRP milling damages are specifically analyzed. Results suggest that the burr and tear damages become serious with the increase of the FOA. The developed model is helpful for further understanding the formation mechanisms of the intralaminar damage, and it is expected that the findings can provide relevant technical supports for the suppression of CFRP milling damage.