基于尺寸优化的水轮发电机上机架轻量化设计

Lightweight Design of Hydro-Generator Upper Bracket Based on Sizing Optimization

上机架是水轮发电机中的重要承载部件。以上机架为研究对象,建立有限元模型,对其强度、刚度和动态特性进行仿真分析。基于结构尺寸优化设计方法,选择上机架结构的8种板厚为设计变量,以正应力和刚度两种设计指标作为约束条件,进行以其质量最小为目标的优化设计。通过复合形法进行寻优迭代,得到上机架优化设计结果。轻量化设计后上机架的最大应力及最大位移均在许用值范围内,其动态特性满足设计要求。上机架结构的质量减小527 kg,减重率达25. 5%,实现了轻量化目标。

The upper bracket is an important bearing component in hydro-generator. Taking upper bracket as research object, the strength, stiffness and dynamic characteristics of upper bracket are simulated and analyzed by means of establishing a finite element model. Based on structure sizing optimization design method, eight kinds of plate thickness are selected as design variables, and two design indexes of normal stress and stiffness are taken as the constraint conditions to optimize upper bracket with minimum mass as the objective. The optimum design of upper bracket is determined by using compound form method with optimization iteration. After lightweight design, the maximum normal stress and maximum displacement of upper bracket are within allowable value range, and the dynamic characteristics meet design requirements. The lightweight design reduces the weight of upper bracket by 527kg and achieves a weight-loss ratio of 25.5%, thus realizing the objective of lightweight.