Abstract: In order to achieve a low vibration design of engine block, verify the correctness of finite element model based on the test method, ensure the undertake of different levels of optimization model using the method of topology and shape optimization, modal frequency and vibration intensity of engine block are taken as optimization objectives, vibration analysis of engine block is made in the simulation, and the body vibration condition distribution are identified in the optimization design. The four cylinder engine block is set as the design objective, the optimal solution design variables are got through the topology optimization and shape optimization method, and then the final optimization scheme with whole layout and detailed design are obtained. The results of optimized structure show that frequencies of each mode are improved, and the vibration intensity value of engine block decreases by 34.8%, then vibration intensity of improved engine block is minimized in a safe area subject to rigidity and strength constraints. Efficiency and precision of the combination method of topology and shape optimization has an obvious enhance, and the feasibility and efficiency of the proposed methods are demonstrated by the experiment.

Key words: Engine block, Low vibration, Shape optimization, Topological optimization