双曲度飞机蒙皮拉伸成形轨迹优化与验证

加载轨迹是决定飞机蒙皮拉伸成形质量的关键因素。对某双曲度蒙皮最大截面采用应变控制的方法，解析分析并推导出拉伸成形加载轨迹范围，并作为初始加载轨迹进行优化；采用最优化理论与算法和有限元数值模拟相结合的优化方法，以减小卸载回弹、提高贴模度为研究目标，以单元最大，主应变和厚度减薄率为约束条件，建立最优化数学模型，得到合理的拉伸成形加载轨迹；在自行研制的拉伸成形试验平台上进行优化结果验证，试验结果表明，成形零件贴模度、应变分布与厚度的均匀程度均有明显提高。

Optimization and Validation of Loading Trajectory for Double Curve Aircraft Skin Stretch Forming Process

Loading trajectory is the key factor for aircraft skin stretch forming. Initial loading traj ectory of double curve skin was designed through the analytic method. The method of combing finite element analysis and optimization algorithms was proposed to acquire the reasonable loading trajectory based on the initial one. Optimization mathematical model was set up in order to reduce springback and to improve the fittability. The reasonable loading trajectory was found through the numerical simulation and Sequential Quadratic Programming optimization algorithm under the restriction of maximal strain and thickness reduction. Experiments were done according to the reasonable loading trajectory. Both numerical simulation and experimental results show that the precision, strain distribution and thickness uniformity of the skin are improved greatly.