High performance machining of lightweight composites and advanced aerospace alloys

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Modern aircraft should ensure reduced fuel consumption as well as reduced CO2, NOx, and noise emission. To this end, airframe and engine manufacturing improvements are necessary. This implies the use of lightweight materials for airframes and engines and advanced turbine materials for discs and blades. The most widely used advanced high strength alloys for airframes are aluminium and refractory alloys and lightweight composite materials like Fiber Reinforced Plastic (FRP), Carbon or Glass Fiber Reinforced Polymer (C/GFRP), and Titanium Metal Matrix Composites (TiMMCs), and for aircraft engines, nickel and titanium alloys. These materials also have great potential for the automotive and biomedical sectors.***After consulting with industry (Pratt&Whitney, RTI, Alcoa, and Bombardier), with this discovery grant, we will focus on evaluation of two materials: Titanium Metal Matrix Composites (TiMMCs) and Carbon Fiber Reinforced Polymer (CFRP). Our preliminary research and a literature review give us the opportunity to define a working hypothesis:***1. It is possible to increase the entire tool life by at least 20% by appropriate control of initial cutting conditions and initial tool wear.***2. Part performance in service can be predicted more accurately using new surface roughness analysis methods and parameters better adapted to composite materials CFRPs, namely using fractal analysis.***3. Tool life estimations can be improved using survival analysis, fractal analysis, and tool wear monitoring based on pattern recognition and Logical Analysis of Data.***Initial cutting conditions, initial cutting tool wear, and their impact on entire tool life when machining TiMMCs have never been studied before. Our preliminary works also show that the application of chaos theory and fractals for analysis of initial cutting conditions and surface roughness is very promising. The theory of fractals has already proven highly effective in many engineering and technology applications and can dramatically change research methods in machining. Consequently, the originality of this work lies in the use of chaos theory and fractals as an approach to understand cutting tool wear and to generate new, meaningful surface roughness parameters for plastics containing fibers (CFRPs). This new approach can also greatly improve the diagnosis and monitoring of cutting tools and the optimization of cutting parameters. We do not claim to revolutionize machining theory but we intend to bring to light a new perspective for the analysis of machining processes.***OBJECTIVES:***The main goal of this research program is to provide new insights on the machinability of new advanced aerospace alloys, Carbon or Glass Fiber Reinforced Polymers (C/GFRP), tool wear modeling and analysis and develop a new surface analysis method and roughness parameters better adapted to composite materials.**