Comparative experimental study and opti̇mi̇zation of machining and abrasive water jet process on composite balistic materials

Use of Polymer Matrix Composites (PMC) has been an increasing trend in Defense and Aviation industries. In aviation, recent top objective is improving fuel economy that leads to use of more composites because of their lightweight structure. In Defense industry, PMCs are mostly use as structural components and shields. Similarly, composites are preferred because of their superior strength-to-weight ratio properties compared to conventional metal alloys. In Ankara region, it can be observed that, use of PMCs has been increasing considerably by major defense companies and their primary suppliers. In this thesis, Aramid Fiber Reinforced Fiber (AFRP) and Ultra-High Modulus Polyethylene (UHMWPE) which used in defence industry as soft ballistic armour used as specimens for trimming, drilling and pocketing experiments using machining and abrasive water jet technology (ASJ) in order to lay out parameter effects on performance measures. Design of experiments (DOE) method has been used for all experiments and results are analyzed with Analysis of Variance (ANOVA) and Response Surface Method (RSM). Also, for selected specimens, cutting surfaces have been imaged by Scanning Electron Microscopy (SEM) to investigate surface morphology. Furthermore, a novel evolutionary optimization method known as Multi-Objective Particle Swarm Optimization (MOPSO) and Nondominated Sorting Genetic Algorithm technique has been applied to find out trade-offs between conflicting performance measures to selected operations and resulting 3D Pareto optimal solutions sets have been generated. As the last stage, all regression-based relations obtained from experiment have been evaluated in order to compare machining and ASJ technologies and their advantages and disadvantages.