Study On The Lightweight Design And Optimization Of The SUV Frame

With multi-performance response and difficult dynamic response simulation, Auto- mobile frame structure lightweight design is a complex issue. as monocoque body structure car For cars with a monocoque body structure, chassis frame as an important structure of auto parts, has great quality and suffered from roads and load of various complex loading, the structure performance affects the overall performance of the vehicle. Frame stiffness plays a decisive role on the bearing capacity and the modal performance of the frame is related to the vehicle’s comfort, thus ensure enough stiffness and good modal performance under the premise, the SUV frame structure lightweight design has important practical and theoretical significance.In the way of frame lightweight, technology and funds severely restricts the application of new materials and new manufacturing technology, the improvement design of the structure becomes an important technology method of lightweight. As working under complex loads, the research of frame structure lightweight considering multi-load-cases, using multi- optimization-method needs to be deeper. In this paper, analysising the frame lightweight status at home and abroad, based on which, the sensitivity analysis is introduced to frame structure lightweight. By size optimization and topology optimization, the target frame becomes lighter. on the basic of topology optimization, the sensitivity analysis of the frame and changing the thickness of frame part, the frame optimization achieves better effect. Firstly, in order to validate the lightweight method,one SUV frame is choosed as an engineering example. Based on 3-D model, the finite element model is established according to finite element modeling specification. The frame mode is analyzed through two methods, experienment and finite element analysis. the accuracy of the finite element model is high, for the two results are very close. Secondly through loading and set constraints in the finite element model of frame, the model and stiffness analysis was doneusing finite element theory and the Optistruct platform, and draws the model performance and stiff performance of the SUV frame, and evaluated model and stiffness of the frame structure, the results show that the model and stiffness of frame meets the conditions of use and there is a great potential of lightweight.In the lightweight design, the parts used in optimization are choosed by analyzing frame parts sensitivity. according to the theory of structural optimization, optimization design variables, constraint function and the objective function are defined, and the mathematic model of the frame structure lightweight design is established.Size optimization,topology optimization design and further optimization combined with sensitivity analysis results are all efficient in the frame lightweight design. The size optimization and topology optimization method separatly decrease 6.3%, 15.5% and 18.1% weight of the frame, what is more the third method combined with topology optimization,sensitivity analysis and changing parts sickness is more effective,with 18.1% weight loss. All the methods achieve the purpose of the frame structure lightweight design. it proves that the lightweight approach of the general frame in structure is feasible.