Study On Lightweight Design Of Transmission Case Under Multiple Loading Cases

Transmission case is an important part of transmission system.With the development of vehicle technology,the complexity and design requirements of transmission case are also continuously improving.The traditional design method is by empirical,which often result in materials west and power density of the vehicle.In this paper,optimization of transmission case was conducted by sensitivity analysis and topology method.The main study contents were as follows:Firstly,the finite element analysis model of transmission case was established,and the dynamic load coefficient of bearings was extracted by the load distribution pre-analysis.The key techniques of the finite element modeling were summarized,including model simplification,geometry cleanup,meshing regulation and quality control,etc.Considering multiple loads,the load of case was calculated by using local coordinates to global coordinate,and the location of strips are developed.Secondly,the modal characteristic and static characteristic of transmission case were conducted for the structural optimization based on finite element analysis method.Modal analysis was mainly aimed at the first ten free modes and constraint modes.Static analysis was forced on the stress and deformation of the structure under seven typical load condition.Then,the topology optimization design of transmission was carried out using the continuum structural topology optimization method.Topology optimization for single loading case may weaken the stiffness of other working condition,a topology optimization for multi-loading cases based on compromise programming method was carried out,and the new topology model of transmission case was reconstructed according to optimization results.Finally,sensitivity analysis of transmission case is carried out.The ratio of strain energy sensitivity and frequency sensitivity is calculated,the optimum variables are extracted and optimized.The model was constructed according to optimization results.By comparing with the original structure,the dynamic and static performances of the new case are improved while the mass is reduced by 46.59 kg,ratio is 10.90%.