초소성 박판 성형 공정의 유한 요소 압력 제어 해석

Abstract

The superplastic blow-forming process of a diaphragm has been analyzed by a finite element method with a pressure cycle control algorithm. The finite element formulation is derived from the equilibrium equations by the principle of virtual work in the form of an approximated, updated Lagrangian formulation for incremental analysis. The formulation is approximated to the finite dimensional space with the use of isoparametric continuum elements. The large inelastic pressure cycle control algorithm is added to the finite element formulation for optimization of the forming time, which is indispensible to shorten the relatively long forming time. The algorithm deals with the maximization of the strain rate sensitivity, the protection of thickness reduction by localized deformation, and the consistency of the desired strain rate. Numerical simulation includes the optimal pressure versus time curve, the pole height versus time, the deformed shape with the variation of time, and the deformed shape with the variation of time, and the distribution of the thickness.