面向7075-T7451铝合金厚板加工变形控制的变向迭代优化方法

A Crossover Iterative Method of Controlling Machining Deformation for 7075-T7451 Aluminum Alloy Thick Plate

依据毛坯分解为去除材料和成形零件两部分,将初始残余应力分为释放应力和有效应力,利用静力平衡条件和弯曲变形理论建立加工变形分析模型及其有限元求解方法。通过现场加工零件后,经与实验测量结果进行对比分析可知,无论是幅值水平还是变形曲线,加工变形的仿真值均有很好的吻合性,两者仅存在10%左右的幅值误差。利用有限元方法求出相邻2个加工位置的零件变形,依据"变形方向相同则步长相等、变形方向相反则步长递减"原则确定下一个加工位置,提出加工位置的变向迭代优化方法。经与企业实际使用的中间位置法相比,变向迭代优化方法能够使得加工变形减小99.79%。

According to separation of a blank into removed materials and formed workpiece, the initial residual stress can be divided into released stress and efficient stress so that the static equilibrium conditions and bend deformation theory were used to deduce the analysis model of machining deformation and its finite element method. And then, the measurement experiment of machined workpieces, carried out in NC machining factory, shows that the simulated results are in good agreement with the measured data for both the amplitude and deformation curves.There is only 10% difference of the amplitude between the two. Finally, based on the simulated values of the machining deformation at two adjacent positions, the signs of machining deformation can be obtained. According the determination principle of the next position that the step is invariant if the signs are the same while the step is decreasing if the signs are different, a crossover iterative method is presented for the optimal machining position. In comparison with middle position method which is frequently employed by the enterprises, the presented crossover iterative method can decrease machining deformation by 99.79%.