A cutting force prediction model for UD-CFRP and MD-CFRP milling based on fracture mechanisms and mechanical properties

Abstract

Due to its exceptional properties, CFRP has become the material of choice for primary load-bearing structural components, such as composite fan blades, in aerospace and other industries. However, its anisotropy, heterogeneity, and unique characteristics make it a challenging material to machine. To address this issue, this paper presents a cutting force prediction model for CFRP milling based on the evolution of fracture mechanisms and material mechanical properties. The model introduces fracture coefficients, slip angle coefficients, and compression coefficients to accurately predict cutting force variations throughout the entire milling process, from tool entry to exit. The model was calibrated using orthogonal cutting experiments and single-angle slot milling experiments on UD-CFRP and further validated through slot milling experiments on UD-CFRP and two types of MD-CFRP, which were all conducted at various angles. Experimental results demonstrate that the proposed model can precisely predict cutting force variations during the entire milling process. Additionally, the model exhibits strong adaptability and scalability, compensating for the variability in CFRP material properties and enabling parameter adjustments for different engineering applications. It can also be applied to different laminate layups, ensuring broader applicability in composite manufacturing. Since the model is built upon fracture mechanisms and material properties, it provides an intuitive representation of the fracture evolution process during machining. The cutting force coefficients effectively characterize the fracture behavior in a straightforward manner. This model demonstrates great potential for machining composite fan blades, particularly in monitoring fracture mechanisms and predicting and controlling damage.