悬置的动态特性及其对动力总成系统的影响
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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。
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.
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。
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.
引文
[1]季晓刚,章应雄,唐新蓬,汽车动力总成悬置研究的发展[J] ,汽车科技, 2004
[2]户元春彦,防振橡胶及其应用[M],北京:中国铁道出版社,1982
[3] Alan N.Gent,橡胶工程[M],北京:化学工业出版社,2002
[4] Mattias Sj?berg,On Dynamic Properties of Rubber Isolators [D],TRITA-FKT 2002:39 ISSN 1103-470X ISRN KTH/FKT/D-02/39-SE
[5] Sj?berg M.,Kari L.,Nonlinear isolator dynamics at finite deformations: An effective hyperelastic, fractional derivative,generalized friction model. [J],Nonlinear Dynamics,2003,33(3):323-336
[6] M.J. Garcia Tarrago,N. Gil-Negrete,J. Vinolas,Viscoelastic models for rubber mounts: influence on the dynamic behaviour of an elastomeric isolated system. [J],Vehicle Design,2009,44(4):303-317
[7]朱石坚,楼京俊,何其伟等,振动理论与隔振技术[M],北京:国防工业出版社2006,147-148
[8] P.B. lindley,K.N.G. Fuller,A.H.Muhr,etc.,Engineering Design with Natural Rubber,NR Technical bulletin [M],1970
[9] G. Ramorino,D. Vetturi,D. Cambiaghi,etc.,Developments in Dynamic Testing of Rubber Compounds: Assessment of non-Linear Effects [J],Polymer Testing ,2003,22,681–687
[10] Roberts. Marvin,Measurement of Dynamic Properties of Rubber [J],Industrial and Engineering Chemistry,1952,44(4):696-702
[11] M.M.Hall,A.G.Thomas,Testing Procedure for Measurement of dynamic properties of Vulcanize rubber [J], Rubber in Engineering Design,1972,65-67
[12]龚积球,龚震震,赵熙雍,橡胶件的工程设计及应用[M],上海:上海交通大学出版社,2003
[13] W. V. Mars,A. Fatemi,A literature survey on fatigue analysis approaches for rubber[J],International Journal of Fatigue,2002,24(9):949-961
[14]庞剑,谌刚,何华,汽车噪声与振动[M],北京:北京理工大学出版社,2006
[15]严济宽,机械振动隔离技术[M],上海:上海科学技术文献出版社,1986
[16] Racca S R.,How to Select Power-train Isolators for Good Performance and Long Service Life[D],SAE Technical Paper Series 821095,1982.
[17]吴炎庭,袁卫平,内燃机噪声振动与控制[M],北京:机械工业出版社,2005
[18]吕振华,范让林,冯振东.汽车动力总成隔振悬置布置的设计思想论析[J],内燃机工程,2004,25(3)
[19]周志革,武一民,崔根群,陈涛,发动机悬置系统参数的优化设计[J],机械设计,2003,1(20)
[20]张义民,机械震动[M],北京:清华大学出版社,2007
[21]徐建,隔振设计规范-理解与应用[M],北京:中国建筑工业出版社,2009
[22] Hans-Peter Willumeit,车辆动力学[M],北京:北京理工大学出版社,1998
[23] Harris C.M.,Piersol,A.G. Harris' Shock and Vibration Handbook (5th Edition)[M],北京:中国石化出版社,2002
[2]户元春彦,防振橡胶及其应用[M],北京:中国铁道出版社,1982
[3] Alan N.Gent,橡胶工程[M],北京:化学工业出版社,2002
[4] Mattias Sj?berg,On Dynamic Properties of Rubber Isolators [D],TRITA-FKT 2002:39 ISSN 1103-470X ISRN KTH/FKT/D-02/39-SE
[5] Sj?berg M.,Kari L.,Nonlinear isolator dynamics at finite deformations: An effective hyperelastic, fractional derivative,generalized friction model. [J],Nonlinear Dynamics,2003,33(3):323-336
[6] M.J. Garcia Tarrago,N. Gil-Negrete,J. Vinolas,Viscoelastic models for rubber mounts: influence on the dynamic behaviour of an elastomeric isolated system. [J],Vehicle Design,2009,44(4):303-317
[7]朱石坚,楼京俊,何其伟等,振动理论与隔振技术[M],北京:国防工业出版社2006,147-148
[8] P.B. lindley,K.N.G. Fuller,A.H.Muhr,etc.,Engineering Design with Natural Rubber,NR Technical bulletin [M],1970
[9] G. Ramorino,D. Vetturi,D. Cambiaghi,etc.,Developments in Dynamic Testing of Rubber Compounds: Assessment of non-Linear Effects [J],Polymer Testing ,2003,22,681–687
[10] Roberts. Marvin,Measurement of Dynamic Properties of Rubber [J],Industrial and Engineering Chemistry,1952,44(4):696-702
[11] M.M.Hall,A.G.Thomas,Testing Procedure for Measurement of dynamic properties of Vulcanize rubber [J], Rubber in Engineering Design,1972,65-67
[12]龚积球,龚震震,赵熙雍,橡胶件的工程设计及应用[M],上海:上海交通大学出版社,2003
[13] W. V. Mars,A. Fatemi,A literature survey on fatigue analysis approaches for rubber[J],International Journal of Fatigue,2002,24(9):949-961
[14]庞剑,谌刚,何华,汽车噪声与振动[M],北京:北京理工大学出版社,2006
[15]严济宽,机械振动隔离技术[M],上海:上海科学技术文献出版社,1986
[16] Racca S R.,How to Select Power-train Isolators for Good Performance and Long Service Life[D],SAE Technical Paper Series 821095,1982.
[17]吴炎庭,袁卫平,内燃机噪声振动与控制[M],北京:机械工业出版社,2005
[18]吕振华,范让林,冯振东.汽车动力总成隔振悬置布置的设计思想论析[J],内燃机工程,2004,25(3)
[19]周志革,武一民,崔根群,陈涛,发动机悬置系统参数的优化设计[J],机械设计,2003,1(20)
[20]张义民,机械震动[M],北京:清华大学出版社,2007
[21]徐建,隔振设计规范-理解与应用[M],北京:中国建筑工业出版社,2009
[22] Hans-Peter Willumeit,车辆动力学[M],北京:北京理工大学出版社,1998
[23] Harris C.M.,Piersol,A.G. Harris' Shock and Vibration Handbook (5th Edition)[M],北京:中国石化出版社,2002