Drilling characteristics and damage analysis of carbon fiber reinforced aluminum laminate

Fiber metal laminates (FML) are widely used in aerospace and automative industries and often require machining, like drilling and milling to obtain desired geometric features or assembly. The present work encompasses investigation on cutting mechanics, damage and performance analysis of fabricated carbon fiber reinforced aluminum laminates (CARALLs) during drilling at different process parameters to improve machining efficiency and minimize structural damage. Drilling experiments are conducted at different feed rates and spindle speeds to assess the influence on thrust force, hole quality, and damage progression. A detailed meso-scale FE modeling framework is developed, incorporating traction-separation laws to capture interlaminar delamination and interface damage. Aluminum layers are modeled for ductile damage, while the Hashin 3D damage model is applied to carbon fiber layers to predict fiber breakage, matrix cracking, and fiber-matrix failures. Results indicate that thrust force increases by approximately 55–65% with feed rate (0.05 to 0.2 mm/rev) and decreases by about 30–35% with spindle speed (1000–3000 rpm). Thrust force variations exhibit alternate peaks due to drill interaction with the layers of aluminum and carbon fiber prepreg present in the laminate, and the same is also identified by finite element (FE) simulation based on tool-work interaction. Different damage modes such as intralaminar matrix damage, fiber failure and matrix loss at the interface of the aluminum and CFRP layers, are identified by scanning electron microscopy. The machining performance is appraised in terms of hole diameter variations, hole quality, and burr height after drilling of the CARALLs at various cutting conditions. Higher feed rates and rotation speed showed the best results.