The Combinatorial Optimization Design Of Frame Of Heavy Commercial Vehicle Under Full Vehicle Environment

With the high speed development of our country’s economy and the increasing request of the production and construction, cargo transportation between different areas is increasing rapidly, so the research and application of heavy commercial vehicle is playing an increasing important role in our life. Vehicle development has gone through a lot of hardship. Today, passenger vehicle designers hold the principle of lighter, faster, safer, greener, while commercial vehicle designers place more energy on car’s safer and stable. Acting as the basic body of the car, the frame is supported by the tyre through the suspending system, front axle and back axle, also it has a very complicated coupling degree with the tyres, cab and cargo tank, so it is very necessary to explore the combinatorial optimization in the full vehicle environment.This paper has introduced the conception of dynamic modal stiffness and sensitivity. Through relevant theory and CAE simulation, the software’s result will show the force and displacement distribution under the free modal and equipped modal. By the methods of dynamic topological optimization, the frame is reshaped and has become a more reasonable structure. Then it introduced generalized inverse optimization.The detailed are as follows:(1) Build three-dimensional modal and FEM modal, the full vehicle include frame, cab and it’s supporting spring, cargo tank, front and back axle. Because the frame is the most important part in this paper, so the frame is divided into main and assistant longeron, nine beams;(2) Compare the simulation results of the frame itself and frame under full vehicle, draw the conclusion that it is very necessary to research under the full vehicle;(3) Introduce the conception of modal stiffness, optimize the frame with dynamic topological method which is the first optimization. The dynamic topological method is adopt substructure method which would reduce the freedom degree significantly. Then employ the generalized inverse method as the second optimization to reduce the frame weight;(4) Compare the frame structure before and after optimize, come the conclusion that the methods are very stable and effective.