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Mechanical Engineering

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Theses and Dissertations

2015

Friction stir welding

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Temperature Control In Friction Stir Welding Using Model Predictive Control, Brandon Scott Taysom Jun 2015

Temperature Control In Friction Stir Welding Using Model Predictive Control, Brandon Scott Taysom

Theses and Dissertations

Temperature is a very important process parameter in Friction Stir Welding (FSW), but until lately active control of temperature has not been practiced. Recently, temperature control via a PID controller has proven to be effective. Model Predictive Control (MPC) is a control method that holds promise, but has not been attempted in FSW before. Two different model forms are developed for MPC and are evaluated. The first is a simple first-order plus dead time (FOPDT) model. The second is the Hybrid Heat Source model and is more complex; it combines the heat source method and a 1D discretized thermal model …


Temperature And Stress Effect Modeling In Fatigue Of H13 Tool Steel At Elevated Temperatures With Applications In Friction Stir Welding, Bradley Valiant Jones Mar 2015

Temperature And Stress Effect Modeling In Fatigue Of H13 Tool Steel At Elevated Temperatures With Applications In Friction Stir Welding, Bradley Valiant Jones

Theses and Dissertations

Tooling reliability is critical to welding success in friction stir welding, but tooling fatigue is not well understood because it occurs in conditions that are often unique to friction stir welding. A fatigue study was conducted on a commonly used tooling material, H13 tool steel, using constant stress loading at temperatures between 300°C and 600°C, and the results are presented. A model is proposed accounting for temperature and stress effects on fatigue life, utilizing a two-region Arrhenius temperature model. A transition in temperature effect on fatigue life is identified. Implications of the temperature effect for friction stir welding suggest that …