以某双对置二冲程柴油机组合结构为主要研究对象，采用模态试验测试方法研究了螺栓预紧力对双对置二冲程柴油机结构刚度的影响规律，并应用有限元数值模拟方法对曲轴箱、进排气管的结构参数和材料对结构刚度的影响规律进行了研究。研究结果表明：预紧力对双对置二冲程柴油机组合结构刚度的影响比较小；进排气管壁厚的增加对提高双对置柴油机结构刚度贡献并不大，材料由铸铁改为铸铝则可减轻组合结构的质量并强化动态刚度；曲轴箱筋板与横侧隔板厚度的增加有利于结构刚度的提高，材料改变对模态固有频率的影响较小，为实现轻量化设计应优先选用铝合金材料。

Taking the composite structure of opposed piston opposed cylinder two-stroke diesel engine as the main study object, the effects of different bolt pre-tightening forces on structure rigidity were studied by using modal testing method and the effects of structure parameters and materials on the structure rigidity of crankcase and intake and exhaust pipes were studied by the finite element numerical simulation. The results show that the pre-tightening forces have little influence on the stiffness of composite structure. The increase of intake and exhaust pipe thickness has little contribution to improving structure rigidity. The material of intake and exhaust pipes that uses cast aluminum instead of cast iron can lighten the weight of composite structure and enhance the dynamic stiffness. The increase of crankcase rib and bulkhead thickness is beneficial to improve the structure rigidity, the material has little effect on natural frequency, and the aluminum alloy material should be preferred for the lightweight design.