应力松弛成形工艺稳健设计
Robust Design of the Stress Relaxation Process

针对热压罐升温速率波动导致的成形质量问题，提出基于容差模型和稳健ε-支持向量机的应力松弛成形工艺稳健设计方法，并给出一种改进的容差计算方法。该方法首先建立工艺参数优化数学模型，以塑性应变的导数为优化目标，以材料性能提升率为优化约束；建立优化目标响应曲面、优化约束响应曲面以及优化约束容差响应曲面，计算得优化约束容差并将其引入优化模型中；利用更新后的优化约束可以计算得到稳健的工艺可行域，最终在可行域内求解得到最佳工艺参数。分别采用原始工艺参数和优化工艺参数进行试验，在升温速率波动的影响下，采用优化工艺参数的试验件全部满足约束条件，而采用原始工艺参数的试验件中有30%不满足要求，验证了本文提出的工艺稳健设计方法的有效性和可靠性。
Aiming at the autoclave forming quality problem caused by heating rate fluctuation, this paper puts forward the robust design method of stress relaxation process based on the tolerance model and robust ε-support vector machines, and gives an improved method to calculate the tolerance. The optimization mathematical model for process parameters is established at first and the derivative of plastic strain and the upgrade rate of material performance are chosen as the optimization goal and optimization constraint respectively. The response surfaces of optimization target, optimization constraint and optimization constraint tolerance are established and the tolerance of optimization constraint is introduced into the optimization model; the robust process feasible domain can be calculated after updating optimization constraints and finally the optimal process parameters can be obtained in feasible domain. The original process parameters and the optimized ones are used respectively to carry out stress relaxation experiments. With the optimized parameters, all parts satisfy the constraints. By contrasting, 30% of parts do not meet the requirements with the original parameters, proving the proposed method is effective and reliable