【作者】 徐敏；

【导师】 叶晓明；

【作者基本信息】 华中科技大学 ， 动力机械及工程， 2009， 硕士

【摘要】 曲柄连杆机构是发动机最核心机构之一,直接影响到发动机的性能和可靠性。随着内燃机向高速、大功率、高负荷方向发展,曲柄连杆机构的工作环境愈加恶劣。因此,研究曲柄连杆机构的动力学特性,分析各运动部件的运动规律、受力情况以及应力/应变的大小与分布,将为发动机的研发设计以及机构优化提供非常有价值的参考依据。本文以CUB100发动机为研究对象,通过实验的方法测取了标定工况下缸内压力随曲轴转角的变化规律。在此基础上,从静力学角度出发,分别建立了CUB100发动机活塞、连杆和曲轴三维有限元分析模型。通过数值模拟方法,求解了活塞、连杆和曲轴三大构件准静态三维应力场分布及应变。通过对计算结果的分析,对构件的强度进行了评价,并提出了改进措施与建议。在静态有限元分析的基础上,通过定义构件间的连接关系,建立了曲柄连杆机构多体动力学仿真模型。通过数值模拟,获得了曲柄连杆机构三维瞬态应力场分布及应变。选取部分曲轴转角下的应力分布云图与静力学计算结果进行对比,分析两者之间的差异及产生的原因。分析表明,曲柄连杆机构动力学仿真计算结果更为合理,更接近于实际情况。更多还原

【Abstract】 The characteristics and reliability of engine is directly affected by the crankshaft connecting rod mechanism, which is therefore one of the most important mechanisms in engine. With the development towards higher speed, larger power, and heavier load, the working environment of internal combustion engine is getting increasingly bad. The dynamic characteristics of crankshaft connecting rod mechanism should be studied to analyze the kinetics, interactive force, and stress distribution and deformation of moving components, which will provide valuable reference data for the design and optimization of engine component structure.CUB100 engine was studied in this thesis, and the changing pattern of cylinder pressure with crankshaft angle was tested under rated working condition. The three dimensional(3-D) finite element models of piston, connecting rod, and crankshaft were established respectively based on static analysis, and meanwhile, the 3-D quasistatic stress distribution and deformation were calculated by numerical simulation. As demonstrated by the calculation result, the strength of mechanism was evaluated and improvement advice was proposed.The static simulation model of crankshaft connecting rod mechanism was established by defining the connecting relationship of component on the basis of static finite element analysis, and the 3-D transient stress distribution and deformation was obtained by numerical simulation. The cloud picture of stress distribution and static calculation under selected crankshaft angles were compared to analyze the difference and cause. As indicated by the analysis result, the dynamic simulation was more reasonable and accurate than static simulation.更多还原