三维边界元法在曲轴结构形状优化中的应用

本文推导了三维边界元表面应力导数和重量导数计算公式,采用作者研制的基于边界元法的三维结构形状优化设计程序,完成了492Q发动机曲轴的形状优化设计,从而把三维形状优化引入到内燃机零件设计中。在计算中采用5个设计变量,允许整个曲柄臂在三维空间上变化,使用一个有效的简化模型,采用约束变尺度优化方法,仅用7次迭代就得到最优解。以原曲柄臂的最大应力、变形水平作为约束条件,使曲柄臂的重量减轻17.2％,取得较显著的优化效果。

APPLICATION OF 3D BOUNDARY ELEMENT METHOD IN SHAPE-STRUCTURAL OPTIMIZATION OF CRANKSHAFTS

Calculation formulae for the surface stress derivatives and weight derivatives of 3D boundary elements are derived. With the aid (f a 3D shape-structural optimum design program developed by the authors, shape-structural optimization design for the crankshaft of the 492Q engine is accomplished. Thus 3D shape optimization is inlreduced into the design of engine elements. Five design parametres are used in the calculation. Allowing variation of the entire crankshaft arm in 3D space, making use of an effective, simplified model and a restricted variable-measure methed of optimization, only 7 reiterations is needed to reach the optimum salu-tion. Taking the maxmum stress/strain level ,>f the original crankshaft arm as the restriction condition, the weight of crankshaft arm is reduced by an amount of 17.2 psrcent, thus resulting in an effect of optimization rather remarkable.