Comparative analysis of dynamic progressive damage and process parameter optimization analysis of drilling BCF/PEEK considering the differences in scale-span modeling

This study focuses on employing dynamic damage behaviors during the drilling of Braided Carbon Fiber-reinforced Poly Ether Ketone (BCF/PEEK), adopting macroscopic and microscopic failure criteria to optimize process parameters. Firstly, four intra-laminar constitutive models of BCF/PEEK were developed, incorporating macroscopic criteria (Hashin, Tsai-Wu, Chang-Chang, etc.) and a modified Micro-Mechanics of Failure (MMF) criterion. Inter-layer delamination and drilling temperature were predicted using a bilinear cohesive element model and heat conduction model. Subsequently, a framework integrating the four failure criteria was established via a user-defined VUMAT subroutine in Abaqus/Explicit, enabling the development of a scale-span thermo-mechanical coupled model for drilling T800S/6 K BCF/PEEK, and the damage behaviors such as heat conduction, inter-fiber bundle and matrix interlaminar interactions, and inter-layer bonding were also predicted. Finally, numerical simulations and experiments were conducted to validate the model and compare simulation results with different failure criteria by analyzing thrust force, temperature and damage morphology on a comprehensive testing platform. A response surface methodology was applied to analyze correlations between drilling process parameters and hole quality to determine the optimal process. Results show that the adopted Tsai-Wu criterion achieves the highest accuracy and efficiency in predicting thrust force, while MMF is more precise for predicting drilling temperature fields and hole-wall damage. For drilling T800S/6 K BCF/PEEK with a twist drill, the minimum drilling temperature occurs at 3000 r/min spindle speed and 40 mm/min feed rate, while lower thrust force and optimal hole quality are achieved at 5000 r/min and 40 mm/min.