【作者】 武欣欣；

【导师】 郭常宁； 李光泽；

【作者基本信息】 上海交通大学 ， 机械工程， 2010， 硕士

【摘要】 动力总成是汽车重要的噪声振动源之一,为提高车辆的乘用性和舒适性,动力总成悬置系统的合理设计成为汽车开发过程中的重要问题之一。橡胶材料长期以来用来做为发动机悬置的弹性材料主体,它的非线性特性对悬置系统的性能有重要影响,因此需要对此进行全面的研究。本研究首先分析了橡胶类高分子聚合物的粘弹性物理特性。橡胶的静态粘弹性的主要表现为应力松弛和蠕变,Maxwell材料模型和Kelvin-Voigt模型可以对这种行为进行数学上的描述,但精度更高的广义模型需要更多的参数来定义。橡胶的动态粘弹性主要表现在滞后现象和能量损耗上,它们除了和材料本身关系密切以外,材料所处的动态环境也有显著的影响。温度、频率对材料的动态特性的影响可以用时温等效方程进行相互转换。此外动态特性还具有振幅依赖特性。本文对发动机悬置的动态特性进行了测试。测试结果表明悬置的动态刚度和损失系数对于频率和振幅都有依赖特性。其中动态刚度对于振幅的变化比较敏感,振幅越大动态刚度越小。损失系数总体上随激励频率的升高而增大,但在某一频率附近有一个大幅度的下降。最后,依据动态测试的结果建立发动机悬置系统的六自由度模型,计算系统在非线性悬置参数下的频率响应。分析结果表明,非线性系统具有特殊的频率响应特性,反映了非线性系统特有的跳跃和滞后现象。更多还原

【Abstract】 This thesis comprises three parts. Firstly mechanical property of elastomer is overviewed and then the testing to explore dynamic behavior of rubber isolators is presented. Finally modeling of power-train system and analysis of system frequency response corresponding to different dynamic scenarios are demonstrated.Maxwell model and Kelvin-Voigt model are employed to describe the rubber static viscoelasticity exhibits as stress release and creep. Being represented as hysteresis and energy loss, dynamic viscoelasticity of rubber material is viewed having correlation with conditions such as temperature,frequency and vibration amplitude,etc under which material works.Testing indicates that dynamic stiffness and loss factor of the rubber isolators relies on frequency and vibration amplitude as well. Dynamic stiffness is sensitive to the variation of vibration amplitude. Loss factor generally increases following the increasing of the excitation frequency.Six(6) Degree Of Freedom model is established to simulate the dynamic behavior of the power train system concentrating on understanding the frequency response. The nonlinear system simulated presents particular characteristics in frequency response aspect. The profile of the vibration transmissibility curve relates with the direction of the frequency sweeping and which reflects the typical skipping and hysteresis phenomena possessed by the nonlinear system.更多还原