Research On Structural Topology Optimization Method Based On Varing Constraint Limits And Simulation Designs Of Bridge Structures

This paper mainly makes researches on the structural topology optimization method with varing constraint limits and gives simulation designs of bridge structures.In engineering practice, the strength reasonable is the basic engineering requirement of the structure, and the stress constraint is very important, so it can't be put to engineering application if structural strength is not considered. For the problem of topology optimization designs of continuum structures, this paper summarizes and analyzes the present status and the development of structural topology optimization method.The optimization interation solving of the continuum structure considering stress constraints requirements is complex, because a element in the design structure includes a design variable, and a lot of constraines and a large amount of sensitivity analysis computation are needed. So this paper focuses on the modeling method of the continuum structure considering stress constraint requirements and stress sensitivity analysis methods. We build an equivalent optimization model for the topological optimization problem. In this model,all element stress constraints of the structure being optimized under a load case are replaced by its most potential active stress constraint and average stress constraint.In order to make the stress constraint approximations hold true during an optimization process, we propose a solving strategy of varying stress limits. And a set of stress sensitivity formulation is derived, and the stress sensitivity computation cost can be greatly reduced by using it. Moreover, the element deletion and adding criterion and a set of structural optimization strategies are given. It can avoid the singular solution of the structure optimization, and solved the problem of the topology optimization of the continuum structure considering stress constraints requirements.Then incorporating the Lagrange multiplier method, this thesis proposes a structural topological optimization designs method considering only stress constraints; and a structural topological optimization method considering displacement and stress constraints.For the mentioned-above proposed methods their procedures are implemented, and some simulation examples dealing with typical structures and bridges are given. The results obtained show that the proposed methods are corrective, and are of good engineering application value.