Application Of ESLm In Optimal Design Of Automobile Structure

A method Equivalent Static Load (ESL) is used to perform structure optimization of vehicle under dynamic load by combining flexible multibody dynamic analysis and structure optimization under static load. And a process flow of applying dynamic response optimization using ESL is proposed. Trunk lid mechanism linkage, connecting rod of engine crankshaft-rod mechanism and lower control arm of double-wishbone suspension were optimized using this method under dynamic load.The main research works are focused in the following aspects:1.A process flow of applying dynamic response optimization using ESL is proposed, including finite element model setting up, connecting joint simplifying, boundary conditions and dynamic load choosing and simplifying, setting up optimization problems and get an optimized structure from the results.2.Trunk lid mechanism linkage was optimized under gravity load, and the connecting rod of engine crankshaft-rod mechanism was optimized using this method under a operation cycle. The optimization effectiveness has been validated by comparing with the results. After optimization, the maximum stress of trunk lid linkage was reduced from 110 MPa to 60 MPa, and mass was reduced by 28.63, the maximum stress of connecting rod was reduced from 421MPa to 365 MPa.3.Lower control arm of double-wishbone front suspension was optimized using equivalent static load method under washboard and alternate rolling road surface while steering. And a new structure was given up to improve the dynamic performance of arm during operation. Comparing with the origin structure, the new one has an advantage of separately lowing down the maximum misses deformation by 15.4% and 27.2%, while mass only increased by 5%.The results from these demonstrations show that applying dynamic response optimization on vehicle structure using equivalent static load method is feasible and can get a better improved structure. First, it can reduce the dependency of engineers' experience. Second, the result can satisfy the dynamic need during operation. Third, it can cut off the time of applying optimization.