Determination of Machining-Induced Damage Characteristics of Fiber Reinforced Plastic Composite Laminates

Machining of fiber reinforced plastic (FRP) components is often needed in spite of the fact that most FRP structures can be made to near net shape. The material removal mechanism of FRP is very difficult as compared with metals due to their inherent inhomogeneity and anisotropy. This results in frequent fiber pullout, delamination, matrix burning, and other damages leading to poor cut surface quality. A finite element model is proposed to quantify the material damage, which has been experimentally validated by means of nondestructive dye-penetrant testing. Good agreement is observed for laminates with fiber orientations up to 60°. Divergence is noticed for higher fiber orientations, and the discrepancies increase with increasing fiber orientation. Proper interfacial properties vis-à-vis machining of FRP materials are considered to be the main reasons for the divergence.