High Fidelity Digital Twin Machining Tool for Quality Informed Composite Drilling

This paper presents a high-fidelity digital twin for hole-drilling in composites to provide a physical mapping between drilling parameters, material system, component geometry, and the resulting material removal. Different from a conventional continuum damage modeling approach, a drilling induced shearing failure was included in the intra-ply damage description in addition to the combined matrix and fiber failure modes. Given a spatial and temporal variation of loading condition at a given material point, a micromechanics model was constructed to simulate thermo-mechanical properties of a composite laminate based on its constitutive properties. In order to capture the fiber orientation dependent shear resistance during drilling, a cutting angle dependent shear strength was introduced based on the relative angle between the local material orientation and the cutting direction. A one way thermomechanical coupling was employed to explore the drilling induced temperature distribution in the vicinity of the drilling hole. An extensive experimental study was performed at the coupon level to validate the performance of the drilling simulation tool and examine the failure mechanisms after drilling. The time histories of the thrust force and torque was measured for the direct comparison with the corresponding model predictions. The in-situ temperature measurement during drilling was accomplished using coupons with embedded thermal couples. Post drilling damage evaluation based on X-ray Computed Tomography was performed on selected coupons to examine the delamination distribution near entrance and exit of a drill bit.