Finite element analysis and simulation study on micromachining of hybrid composite stacks using Micro Ultrasonic Machining process

Hybrid composites stacks are multi-material laminates which find extensive applications in industries such as aerospace, automobile, and electronics and so on. Most hybrid composites consist of multiple layers of fiber composites and metal sheets stacked together. These composite stacks have excellent physical and mechanical properties including high strength, high hardness, high stiffness, excellent fatigue resistance and low thermal expansion. Micromachining of these materials require particular attention as conventional methods such as micro-drilling is extremely challenging considering the non-homogeneous structure and anisotropic nature of the material layers. Micro Ultrasonic Machining (mu USM) is a manufacturing process capable of machining such difficult-to-machine materials with ultraprecision. Experimental study showed that mu USM process could successfully machine hybrid composite stacks at micron scale with a relatively good surface finish. This research uses finite element simulation technique to investigate the material removal during the mu USM process for micromachining hybrid composite stacks. The effects of critical process parameters including the amplitude of vibration, feed rate and tool material on the cavity depth, cutting force and equivalent stress distribution are studied. The outcome of this research can be utilized to further our understanding of performing precision machining of hybrid composite stacks for use in several critical engineering applications.