以应变能最小为目标的航空薄壁件装夹优化方法

A clamping optimization method for aviation thin-walled parts with the aim of minimizing strain energy

  • 摘要: 在薄壁件装夹过程中,定位布局、夹紧布局及夹紧顺序等参数的不同,导致薄壁件变形程度也不同。现有研究大多以节点法向变形最小为优化目标,忽略了不同方向上的变形程度以及不同区域的装夹应力分布影响,提出以应变能最小为目标进行航空薄壁件装夹方案优化,当整体应变能最小时,薄壁件变形程度较小,应力分布也较均匀。应用拉丁超立方采样和有限元软件生成样本数据,建立最小化整体应变能为目标,定位元件位置为决策变量的BP神经网络预测模型,并应用遗传算法优化定位布局。在薄壁件装夹过程中,定位与夹紧是相互联系的过程,在定位布局优化的基础上,构建装夹顺序、夹紧位置与整体应变能之间的非线性映射关系,对所建立的映射关系迭代寻优,确定最优装夹顺序与装夹位置。以曲面薄壁件作为应用实例,验证所提方法的正确性和有效性。

     

    Abstract: In the clamping process of thin-walled parts, different parameters such as positioning layout, clamping layout and clamping sequence lead to different degrees of deformation of thin-walled parts. Most of existing research by the method of node to the objective function is minimum deformation, deformation degree and ignores all directions of different regions of the stress distribution of the clamping effect, puts forward the minimum strain energy as the target air thin-walled clamping scheme optimization, the most hours, when the whole strain energy thin-walled deformation degree is small, the stress distribution is more uniform.Latin hypercube sampling and finite element software are used to generate sample data.A BP neural network prediction model is established to minimize the global strain energy, and the location of positioning elements is the decision variable. In the clamping process of thin-walled parts, positioning and clamping are interrelated processes. Based on the optimization of positioning layout, the nonlinear mapping relationship between clamping sequence, clamping position and overall strain energy is constructed. The established mapping relationship is iteratively optimized to determine the optimal clamping sequence and clamping position. The correctness and effectiveness of the proposed method are verified by an application example of a curved thin-walled piece.

     

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