自适应形状优化设计研究

目的提出一种基于结构边界强度的自适应形状优化设计的新方法，利用该方法对一大功率、高效柴油机的主轴承盖进行形状优化。方法以有限元模型中结构边界上的节点应力值来驱动节点位置的变化，利用物体热胀冷缩的数学模型，根据边界节点的应力值与给定的应力目标值，在边界节点上施加相应的温度载荷，使应力大于目标值的节点膨胀，反之收缩，最后达到边界上的节点应力均趋于给定的应力目标值，结果通过对一柴油机主轴承盖的优化，该主轴承盖的拱形外边界部分达到等强度，使之在满足强度要求的情况下质量减少到总量的５５％，结论该方法高效、可靠，适用于受机械载荷作用连续体的内、外边界的形状优化设计。

Study on Adaptive Shape Optimization

Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's property of thermal expansion and cooling shrinkage,the load which is proportional to the difference between the nodes' stress and their respective objective stress were applied to the corresponding variable nodes on the boundary.The thermal load made the nodes whose stress is greater than their objective stress expand along the boundary's normal direction and the nodes whose stress is less than objec- tive stress shrink in the opposite direction , This process would repeat until the stress on the boundary nodes was converge to the objective stress. Results The satisfied results have been obtained when optimizing an engine bearing cap.The mass of the bearing cap is reduced to 55 percent of the total. Conclusion ASOP is an efficient,practical and reliable method which is suitable for optimizing the shape of the continuous structures.