This paper presents a methodology for designing optimal process parameters for forging operations. The nonlinear rigid viscoplastic finite element (FE) method is used for deformation and thermal analyses. From the FE model a state space system is developed for representing the coupled deformation and thermal behavior of the metal forming system. Constraints are imposed on the strain rate and temperature of the deforming work-piece for obtaining the desired physical/microstructural properties in the final product. The linear quadratic regulator (LQR) theory for finite time control is used in designing the initial die temperature and optimal ram velocity schedules. The approach is demonstrated on a plane strain channel section forging under nonisothermal conditions.

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This paper presents a systematic methodology for the design of process parameters for nonisothermal forgings. The finite element approach is used for deformation and thermal analyses, and an optimal control strategy is used for the process parameter design. A state-space model is developed for representing the coupled deformation and thermal behavior using rigid viscoplastic formulation. Design constraints on strain-rates and temperature variation are imposed for achieving the desired forging conditions. The linear quadratic regulator (LQR) theory for finite time control is used in designing the ram velocity and initial die temperature. The approach is demonstrated on an axisymmetric disc forging and a plane strain channel section forging, under nonisothermal conditions.