轿车车身疲劳寿命的集成化分析
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摘要
承受交变载荷的结构都会产生疲劳,由此带来的疲劳破坏会带来巨大的损失。因此,承受交变载荷的结构都需进行疲劳强度设计。车身作为车辆的主要承载构件,也要承受交变载荷的作用,因此也要进行疲劳强度设计。目前,车身疲劳寿命的评价主要靠台架试验和道路试验。试验周期长,费用高。随着计算机技术的发展,有限元技术在现代汽车产品开发中发挥着越来越重要的作用,几乎贯穿了汽车设计的全过程。采用CAE技术,可以大大缩短车辆的开发周期,降低开发成本,提高设计质量。本文即利用有限元法,分析了某款轿车车身的疲劳寿命。
首先,本文建立了白车身的有限元模型,并通过实验模态对模型进行了修正。对修正后的白车身模型进行了弯曲刚度和扭转刚度分析,并做了系统的评价。在白车身有限元模型的基础上,建立整个车身的有限元模型。进而进行了车身强度的分析。
在MSC.Nastran中,对整车车身进行模态分析,生成了车身模态中性文件,进而在Adams中建立了刚柔耦合的多体动力学模型。通过多体动力学分析,得到了车身的DAC文件。利用模态结果文件和DAC文件对车身进行了疲劳寿命分析。分析发现,车身底板疲劳强度不足,需要加强。
最后,通过结构改进,使得车身的各项性能得以提高,为结构的设计改进提供了有力的支持。
Structural fatigue occurs by alternating loads, and the resulting fracture will cause huge losses. Structure bearing alternating loads needed to make fatigue design. As the main bearing component of the vehicle, body bears alternating load. Therefore fatigue design must be implemented. At present, the estimate methods of the car body fatigue are bench test and road test. Test cycle is long, and it`s expensive. With the development of computer technology, finite element technology plays an increasingly important role in the modern automotive product development. Using CAE technology, it can greatly reduce the vehicle's development cycle, reduce development costs and improve design quality. Using the finite element method, fatigue life analysis is executed in a certain type of car.
First, the finite element model of the BIW is established. The model is modified by modal experiments. Then, bend stiffness and torsion stiffness analysis are executed, and systematic evaluation of the results is executed. On the basis of the BIW`s finite element model, the finite element model of the whole body is created. And then, the strength analysis is executed.
Modal Neutral File of the body is generated through modal analysis in Nastran. And then a Rigid-flexible coupling multibody dynamics model is created in Adams. DAC files of the body are generated after multi-body dynamics analysis. In MSC.Fatigue, the fatigue life analysis of the body is executed using the results file of the model analysis and the DAC mode file. It shows insufficient fatigue strength in the back floor of the car body. These places need to be strengthened.
Finally, the performances of the car body are enhanced by structural improvements. This provides a strong support for the structural design improvements.
首先,本文建立了白车身的有限元模型,并通过实验模态对模型进行了修正。对修正后的白车身模型进行了弯曲刚度和扭转刚度分析,并做了系统的评价。在白车身有限元模型的基础上,建立整个车身的有限元模型。进而进行了车身强度的分析。
在MSC.Nastran中,对整车车身进行模态分析,生成了车身模态中性文件,进而在Adams中建立了刚柔耦合的多体动力学模型。通过多体动力学分析,得到了车身的DAC文件。利用模态结果文件和DAC文件对车身进行了疲劳寿命分析。分析发现,车身底板疲劳强度不足,需要加强。
最后,通过结构改进,使得车身的各项性能得以提高,为结构的设计改进提供了有力的支持。
Structural fatigue occurs by alternating loads, and the resulting fracture will cause huge losses. Structure bearing alternating loads needed to make fatigue design. As the main bearing component of the vehicle, body bears alternating load. Therefore fatigue design must be implemented. At present, the estimate methods of the car body fatigue are bench test and road test. Test cycle is long, and it`s expensive. With the development of computer technology, finite element technology plays an increasingly important role in the modern automotive product development. Using CAE technology, it can greatly reduce the vehicle's development cycle, reduce development costs and improve design quality. Using the finite element method, fatigue life analysis is executed in a certain type of car.
First, the finite element model of the BIW is established. The model is modified by modal experiments. Then, bend stiffness and torsion stiffness analysis are executed, and systematic evaluation of the results is executed. On the basis of the BIW`s finite element model, the finite element model of the whole body is created. And then, the strength analysis is executed.
Modal Neutral File of the body is generated through modal analysis in Nastran. And then a Rigid-flexible coupling multibody dynamics model is created in Adams. DAC files of the body are generated after multi-body dynamics analysis. In MSC.Fatigue, the fatigue life analysis of the body is executed using the results file of the model analysis and the DAC mode file. It shows insufficient fatigue strength in the back floor of the car body. These places need to be strengthened.
Finally, the performances of the car body are enhanced by structural improvements. This provides a strong support for the structural design improvements.
引文
[1] I.M. Austen.工程中的一体化疲劳耐久管理.中国机械工程,1998,9(11):3‐7
[2]结构疲劳强度设计.中国机械工程手册第二版.机械设计基础卷.第3篇第6章.机械工业出版社,1996
[3]黄金陵主编.汽车车身设计.北京:机械工业出版社.2007
[4]周传月,郑红霞,罗慧强等编著. MSC Fatigue疲劳分析应用与实例[M].北京:科学出版社.2005?
[5]林晓斌.虚拟疲劳寿命与工程设计.虚拟工程与科学.北京:中国科协青年科学家论坛, 2001. 100-110
[6]王勖成编著.有限单元法.北京:清华大学出版社.2003
[7]肖攀,周定陆.基于台架试验方法的车身疲劳分析.计算机辅助工程,2006,15(增): 217-218
[8]吴利辉,陈昌明.基于虚拟样机的白车身疲劳寿命分析.北京汽车,2007,(3):30-33
[9]吴利辉,陈昌明.基于随机震动方法的白车身疲劳寿命分析.北京汽车,2007,(5):19-22
[10]杜中哲,朱平,何俊,韩旭.基于有限元法的轿车车身结构及焊点疲劳寿命分析.汽车工程,2006,28(10):944-947
[11]周毅,许先锋.集成化疲劳分析在车身开发中的应用.计算机辅助工程,2006, 9(增): 244-246
[12]孙凌玉,吕振华.利用计算机仿真技术预测车身零件疲劳寿命.汽车工程,2001, 23(6) : 389-391
[13]冯刚.白车身台架试验方法及疲劳寿命分析:[工程硕士学位论文].重庆:重庆大学, 2005
[14]程亚军.货车车体焊接结构疲劳寿命关键技术研究:[硕士学位论文].辽宁:大连交通大学,2005
[15]单勇.客车车身骨架的疲劳分析方法研究:[硕士学位论文].吉林:吉林大学,2006
[16]高书娜.轿车车身结构分析与设计技术研究:[硕士学位论文].重庆:重庆大学,2006
[17]王攀.SC6350白车身疲劳寿命台架试验方法的研究:[硕士学位论文].重庆:重庆大学,2004
[18]曹群豪.军用客车车身骨架结构随机震动特性与疲劳强度分析:[硕士学位论文].上海:上海交通大学,2007
[19]张泓.4G1发动机支架疲劳性能分析研究:[硕士学位论文].吉林:东北林业大学, 2007
[20]宋传平.现代汽车设计分析[J].汽车工业研究,2004,(12):42-43
[21] MSC Fatigue User’s Manual[K].?
[22]王勖成编著.有限单元法.北京:清华大学出版社,2003
[23] Hyperworks 10.0 User’s Manual[K].
[24] MSC Nastran User’s Manual[K].?
[25]闫庆伟,张向奎.轿车白车身有限元建模与静态特性分析.天津汽车,2008,11:42-44
[26]陈鑫.轿车车身静态刚度分析及结构优化研究:[吉林大学硕士研究生论文].吉林:吉林大学,2003.3?
[27]程亚军.货车车体焊接结构疲劳寿命关键技术研究:[硕士学位论文].辽宁:大连交通大学, 2005?
[28] MSC Adams User’s Manual[K]?
[29]张洪欣.汽车设计[M].北京:机械工业出版社,1996.
[30]张家瑞.汽车构造第二版[M].北京:机械工业出版社,2004.
[31] Chang-Ro Lee, Jeong-Won Kim, John O. Hallquist, Yuan Zhang, Akbar D. Farahani. Validation of a FEA Tire Model for Vehicle Dynamic Analysis and Full Vehicle Real Time Proving Ground Simulations. SAE.971100
[32] Yuan Zhang, Paul Xiao, Tim Palmer and Akbar Farahani, Vehicle Chassis/Suspension Dynamics Analysis Finite Element Model vs. igid Body Model, SAE.980900
[33] B. W. Deutshel, R. B. katrlilt, etc. Improving vehicle response to engine and road excitation using interactive grphics and modal reanalysis methods. SAE paper 900817
[34] James G H,Garne T G. The natural excitation technique(NExT) for modal parameter extraction from operating structures. Int. J. of Analytical&Experimental Modal Analysis, 1995;10(4):260-277
[35] Matteo Palmonella, Michael I. Friswell, John E. Mottershead, ArthurW. Lees. Guidelines for the implementation of the CWELD and ACM2 spot weld models in structural dynamics. Finite Elements in Analysis and Design 41 (2004) 193-210
[36] Yung-Li Lee, Two Pan, Richard B. Hathaway. Fatigue Testing and Analysis: theory and practice [M]. Wiley, New York, 2003.
[37] Fatigue Analysis Techniques using eta/VPG Virtual Proving Ground Inc. 2002.7
[38] Shaun Richmond. Finite Element Analysis of freight car structures for fatigue life prediction Proceedings of Joint Rail Conference 2006-94049
[39]孙凌玉,谢军,丁春生等.汽车车身结构动力学建模方法研究.机械工程学报,1999.35
[40]吴胜军,储招友.基于HyperWorks的车身地板的有限元分析.客车技术,2006(3):19-21
[41]徐灏.概率疲劳.沈阳:东北大学出版社,1994.
[42]王学颜,宋广惠.结构疲劳强度设计与失效分析.北京:兵器工业出版社,1992.
[2]结构疲劳强度设计.中国机械工程手册第二版.机械设计基础卷.第3篇第6章.机械工业出版社,1996
[3]黄金陵主编.汽车车身设计.北京:机械工业出版社.2007
[4]周传月,郑红霞,罗慧强等编著. MSC Fatigue疲劳分析应用与实例[M].北京:科学出版社.2005?
[5]林晓斌.虚拟疲劳寿命与工程设计.虚拟工程与科学.北京:中国科协青年科学家论坛, 2001. 100-110
[6]王勖成编著.有限单元法.北京:清华大学出版社.2003
[7]肖攀,周定陆.基于台架试验方法的车身疲劳分析.计算机辅助工程,2006,15(增): 217-218
[8]吴利辉,陈昌明.基于虚拟样机的白车身疲劳寿命分析.北京汽车,2007,(3):30-33
[9]吴利辉,陈昌明.基于随机震动方法的白车身疲劳寿命分析.北京汽车,2007,(5):19-22
[10]杜中哲,朱平,何俊,韩旭.基于有限元法的轿车车身结构及焊点疲劳寿命分析.汽车工程,2006,28(10):944-947
[11]周毅,许先锋.集成化疲劳分析在车身开发中的应用.计算机辅助工程,2006, 9(增): 244-246
[12]孙凌玉,吕振华.利用计算机仿真技术预测车身零件疲劳寿命.汽车工程,2001, 23(6) : 389-391
[13]冯刚.白车身台架试验方法及疲劳寿命分析:[工程硕士学位论文].重庆:重庆大学, 2005
[14]程亚军.货车车体焊接结构疲劳寿命关键技术研究:[硕士学位论文].辽宁:大连交通大学,2005
[15]单勇.客车车身骨架的疲劳分析方法研究:[硕士学位论文].吉林:吉林大学,2006
[16]高书娜.轿车车身结构分析与设计技术研究:[硕士学位论文].重庆:重庆大学,2006
[17]王攀.SC6350白车身疲劳寿命台架试验方法的研究:[硕士学位论文].重庆:重庆大学,2004
[18]曹群豪.军用客车车身骨架结构随机震动特性与疲劳强度分析:[硕士学位论文].上海:上海交通大学,2007
[19]张泓.4G1发动机支架疲劳性能分析研究:[硕士学位论文].吉林:东北林业大学, 2007
[20]宋传平.现代汽车设计分析[J].汽车工业研究,2004,(12):42-43
[21] MSC Fatigue User’s Manual[K].?
[22]王勖成编著.有限单元法.北京:清华大学出版社,2003
[23] Hyperworks 10.0 User’s Manual[K].
[24] MSC Nastran User’s Manual[K].?
[25]闫庆伟,张向奎.轿车白车身有限元建模与静态特性分析.天津汽车,2008,11:42-44
[26]陈鑫.轿车车身静态刚度分析及结构优化研究:[吉林大学硕士研究生论文].吉林:吉林大学,2003.3?
[27]程亚军.货车车体焊接结构疲劳寿命关键技术研究:[硕士学位论文].辽宁:大连交通大学, 2005?
[28] MSC Adams User’s Manual[K]?
[29]张洪欣.汽车设计[M].北京:机械工业出版社,1996.
[30]张家瑞.汽车构造第二版[M].北京:机械工业出版社,2004.
[31] Chang-Ro Lee, Jeong-Won Kim, John O. Hallquist, Yuan Zhang, Akbar D. Farahani. Validation of a FEA Tire Model for Vehicle Dynamic Analysis and Full Vehicle Real Time Proving Ground Simulations. SAE.971100
[32] Yuan Zhang, Paul Xiao, Tim Palmer and Akbar Farahani, Vehicle Chassis/Suspension Dynamics Analysis Finite Element Model vs. igid Body Model, SAE.980900
[33] B. W. Deutshel, R. B. katrlilt, etc. Improving vehicle response to engine and road excitation using interactive grphics and modal reanalysis methods. SAE paper 900817
[34] James G H,Garne T G. The natural excitation technique(NExT) for modal parameter extraction from operating structures. Int. J. of Analytical&Experimental Modal Analysis, 1995;10(4):260-277
[35] Matteo Palmonella, Michael I. Friswell, John E. Mottershead, ArthurW. Lees. Guidelines for the implementation of the CWELD and ACM2 spot weld models in structural dynamics. Finite Elements in Analysis and Design 41 (2004) 193-210
[36] Yung-Li Lee, Two Pan, Richard B. Hathaway. Fatigue Testing and Analysis: theory and practice [M]. Wiley, New York, 2003.
[37] Fatigue Analysis Techniques using eta/VPG Virtual Proving Ground Inc. 2002.7
[38] Shaun Richmond. Finite Element Analysis of freight car structures for fatigue life prediction Proceedings of Joint Rail Conference 2006-94049
[39]孙凌玉,谢军,丁春生等.汽车车身结构动力学建模方法研究.机械工程学报,1999.35
[40]吴胜军,储招友.基于HyperWorks的车身地板的有限元分析.客车技术,2006(3):19-21
[41]徐灏.概率疲劳.沈阳:东北大学出版社,1994.
[42]王学颜,宋广惠.结构疲劳强度设计与失效分析.北京:兵器工业出版社,1992.