Characterisation on the effects of workpiece microstructure and process parameters on resiudal stresses generated during machining

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The long term objective is to numerically model the effects of workpiece micro structure and process parameters on residual stresses generate in the machined surface after single point turning. Short term research is comprised of studies on a) develop a combine numerical and experimental method to determine the friction coefficient along the tool-chip interface and investigate the operating boundary for this method, b) design using the Arbitrary Lagrangian Eulerian formulation technique to simulate the effects of sequential cut, cutting edge radius and feed on residual stresses, c) develop a numerical model to simulate the effects of workpiece microstructure and phase transformation on residual stresses and d) numerically and experimentally investigate the effects of flank wear length, cutting edge radius to feed ratio, tool coating, and process parameters on residual stresses. This research will develop a unique methodology to acquire actual friction coefficient induced during machining by using both numerical and experimental approaches. The effect of tool holder on tool deflection during the cutting process will also be modeled. Influence of sequential cut on the final residual stress profile will also be analyzed. The F.E. model developed to predict residual stresses will be based on either an implicit solver or analytical approach, which will reduced computational time substantially. Models will also be developed to predict the highly complex effects of phase transformation and workpiece micro structure on residual stresses. The significant of this research is to enhance the knowledge on modeling of residual stresses, which will enable researchers to optimize machining parameters for fatigue loaded components in the aerospace, medical and automotive sectors in terms of maximization of compressive residual stresses in both magnitude and penetration depth. Furthermore, this technology will assist design for manufacture protocol in reduction of post machining stages like shot peening, improved fatigue performance and reduce part distortion induced by residual stresses. Residual stress seminar will be organised at McMaster for Mechanical, Materials & Manufacturing engineers to present research discovery from this grant.