关键词: 自由阻尼结构, 模态损耗因子, 改进优化准则法, 减振特性, 动力学拓扑优化

Abstract: Aimed to solve the problems of topology optimization of free damping structures, the finite element method of modal strain energy was adopted, the relative density of the units was designed as the topological variables and the changes of material amount and frequencies were taken as the constraint conditions. A topology optimization model with the weighted sum of multi-modal loss factors was built as objective function. The expression of objective function to the design variable sensitivity was deduced. Considering that when the conventional criterion method was used for structural dynamic optimization,the objective function was non-convexity and the negative design variable appeared during its iteration, so that the optimization results did not converge or fell into local optimization. On the basis of the general optimal criteria, the iteration improvement was processed in the sense of mathematics. This method solved the problems of the negative design variables or iterative divergence, ensured all the topological variables to be involved in the processes of iteration. The free damping plates were simulated by ANSYS programming as well as the morphological step of structure was controlled by the MAC factor. The results show: when the damping material volumes are controlled to 60% pre-optimized volume by improved algorithm, after several iterations, the objective functions and topological configurations of each order tend to be stable, the cell intermediate density region is relatively small, and the free damping structures achieve an effective damping.

Key words: free damping structure, modal loss factor, modified optimality criterion method, damping characteristics, dynamics topology optimization