考虑焊接螺母的排气管支架疲劳优化研究
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摘要
针对在四通道液压振动台及试车场路试过程中,某样车排气管支架出现的焊接螺母疲劳开裂问题,在考虑焊接螺母焊点和螺栓预紧力的前提下,建立开裂支架的局部非线性有限元模型,根据Miner线性疲劳累计损伤理论和材料S-N曲线,对正弦信号激励下的排气管支架进行疲劳分析。在此基础上,提出优化方案,进行仿真疲劳寿命预测,并对简化后的局部排气管支架模型进行疲劳验证,优化前后的仿真模型寿命曲线趋势与试验结果基本吻合,危险区域分布与试验一致。针对焊接螺母或者螺栓连接的支架疲劳开裂问题,在考虑螺栓预紧力的基础上,建立局部模型疲劳分析并结合试验验证,提出优化方案解决问题。试验结果表明,该流程方法对解决实际问题具有一定的借鉴意义。
Aiming at the fatigue crack problem of the weld nut in an exhaust pipe support bracket of aprototype vehicle during the road test on the hydraulic shaker and on the proving ground,a simplifiednonlinear finite element model was established considering the projection weld nuts and bolt pretension.The Miner's linear fatigue damage accumulation rule and the S-N curve of the materials were used topredict the fatigue life of the bracket under the sinusoidal excitation. Based on the fatigue simulationresults,an optimized structure was presented and then the fatigue life was predicted. The lab fatiguetests were carried out to verify the simplified finite-element-model and the fatigue life and dangerous areasobtained from the FEA agree with the test results. Finally,the optimization measures were presented tosolve the fatigue crack problem of the weld nut. The proposed method has some certain significance toserve as a reference.
Aiming at the fatigue crack problem of the weld nut in an exhaust pipe support bracket of aprototype vehicle during the road test on the hydraulic shaker and on the proving ground,a simplifiednonlinear finite element model was established considering the projection weld nuts and bolt pretension.The Miner's linear fatigue damage accumulation rule and the S-N curve of the materials were used topredict the fatigue life of the bracket under the sinusoidal excitation. Based on the fatigue simulationresults,an optimized structure was presented and then the fatigue life was predicted. The lab fatiguetests were carried out to verify the simplified finite-element-model and the fatigue life and dangerous areasobtained from the FEA agree with the test results. Finally,the optimization measures were presented tosolve the fatigue crack problem of the weld nut. The proposed method has some certain significance toserve as a reference.
引文
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[9]马宇,郑民欣.基于ANSYS的筒体法兰的疲劳强度分析[J].现代机械,2011(4):46-48.MA Yu,ZHENG Minxin.Fatigue Strength Analysis of the Cylinder Flange Based on ANSYS[J].Modern Machinery,2011(4):46-48.(in Chinese)
[10]黄开放,金建新.基于虚拟材料方法的螺栓预紧力模拟的研究工艺方法[J].机械设计与制造,2012,8(8):148-150.HUANG Kaifang,JIN Jianxin.Research on Bolt Preload Simulation Based on Virtual Material Method[J].Machinery Design&Manufacture,2012,8(8):148-150.(in Chinese)
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[12]MINER M A.Cumulative Damage in Fatigue[J].Journal of Applied Mechanics Review,1945(3):159-164.
[2]朱品昌,马力.轿车排气管挂钩刚度优化分析[J].计算机辅助工程,2012,21(2):18-20,24ZHU Pinchang,MA Li.Optimization Analysis on Car Exhaust Pipe Hook Stiffness[J].Computer Aided Engineering,2012,21(2):18-20,24.(in Chinese)
[3]王玉超,张利明,周建文,等.传递函数法解决排气系统挂钩的共振问题[J].汽车技术,2011(2):30-33.WANG Yuchao,ZHANG Liming,ZHOU Jianwen,et al.Elimination of Resonance Defect of Exhaust System Hanger with Transfer Function Method[J].Automobile Technology,2011(2):30-33.(in Chinese)
[4]上官文斌,黄志,贺良勇,等.汽车排气系统吊耳动刚度优化方法的研究[J].振动与冲击,2010,29(1):100-152.SHANGGUAN Wenbin,HUANG Zhi,HE Liangyong,et al.Modeling and Optimization Method of Dynamic Stiffness for Automotive Exhaust System Hangers[J].Journal of Vibration and Shock,2010,29(1):100-152.(in Chinese)
[5]唐大庆.高强钢与螺母凸焊参数的正交设计[C]//2016中国汽车工程学会年会论文集.北京:中国汽车工程学会,2016:1523-1526.TANG Daqing.Parameters Design for High-Strength/Nut Projection Welding Byorthogonality[C]//Proceedings of the 2016 Annual Meeting of the SAE-China.Beijing:SAE-China,2016:1523-1526.(in Chinese)
[6]潘青,程猛,任涛,等.白车身凸焊螺母焊接防错防漏系统的应用[J].机械制造,2013,51(8):50-53.PAN Qing,CHENG Meng,REN Tao,et al.Application of Fault and Leakage Prevention System for Welding Nut BIW[J].Machinery,2013,51(8):50-53.(in Chinese)
[7]张志慧.凸焊螺母的焊接工艺研究[J].燕山大学学报,2001,25(3):245-248.ZHANG Zhihui.Welding Process for Projection Welding Nut[J].Journal of Yanshan University,2001,25(3):245-248.(in Chinese)
[8]王晓华,崔志琴.汽车车身的焊接工艺方法[J].机械工程与自动化,2011,169(6):100-102.WANG Xiaohua,CUI Zhiqin.Discussion on Welding Process of Vehicle Body[J].Mechanical Engineer&Automation,2011,169(6):100-102.(in Chinese)
[9]马宇,郑民欣.基于ANSYS的筒体法兰的疲劳强度分析[J].现代机械,2011(4):46-48.MA Yu,ZHENG Minxin.Fatigue Strength Analysis of the Cylinder Flange Based on ANSYS[J].Modern Machinery,2011(4):46-48.(in Chinese)
[10]黄开放,金建新.基于虚拟材料方法的螺栓预紧力模拟的研究工艺方法[J].机械设计与制造,2012,8(8):148-150.HUANG Kaifang,JIN Jianxin.Research on Bolt Preload Simulation Based on Virtual Material Method[J].Machinery Design&Manufacture,2012,8(8):148-150.(in Chinese)
[11]徐颢.疲劳强度[M].北京:高等教育出版社,1988.XU Hao.Fatigue Strength[M].Beijing:Higher Education Press,1988.(in Chinese)
[12]MINER M A.Cumulative Damage in Fatigue[J].Journal of Applied Mechanics Review,1945(3):159-164.