单缸柴油机排气管疲劳开裂的仿真分析
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摘要
针对单缸柴油机排气管的开裂问题,提出了基于等效振动和材料温度效应的热机耦合方法,利用有限元法计算排气管的温度和应力,并依据修正的Miner法则和线性累计损伤理论,考虑应力梯度、表面粗糙度和温度的影响,预测排气管结构的疲劳危险位置。结果表明:排气管失效的原因是由于上下方向刚度不足,存在热模态共振风险,疲劳安全系数不足导致开裂;原失效和增加支撑的排气管疲劳安全系数分别为1.06和1.6,仿真预测结果与实际符合一致。
Aiming at exhaust pipe cracking failure of a single cylinder diesel engine, thermo-mechanical coupling approach based on equivalent vibration and material temperature effect was presented, and then varied stress was simulated using Finite Element Method. According to the modified Miner law and linear cumulative damage theory, considering stress gradient, surface roughness and temperature, dangerous position of exhaust pipe structure is predicted. The results show that exhaust pipe cracking is due to lack of stiffness in upper and lower direction. There is a risk of thermal modal resonance, and insufficient safety factor causes failure. Fatigue safety factor of original and support improved is 1.06 and 1.6, respectively. The predicted results agree well with measurements.
Aiming at exhaust pipe cracking failure of a single cylinder diesel engine, thermo-mechanical coupling approach based on equivalent vibration and material temperature effect was presented, and then varied stress was simulated using Finite Element Method. According to the modified Miner law and linear cumulative damage theory, considering stress gradient, surface roughness and temperature, dangerous position of exhaust pipe structure is predicted. The results show that exhaust pipe cracking is due to lack of stiffness in upper and lower direction. There is a risk of thermal modal resonance, and insufficient safety factor causes failure. Fatigue safety factor of original and support improved is 1.06 and 1.6, respectively. The predicted results agree well with measurements.
引文
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[4] 马子远,毕玉华,申立中,等. 排气管热负荷结构影响因素分析[J]. 机械强度, 2016, 38(02): 348-355.MA ZiYuan, BI YuHua, SHEN LiZhong, et al. Study on structure influence factor of diesel engine exhaust manifold thermal load[J]. Journal of Mechanical Strength, 2016, 38(2): 348-355(In Chinese).
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[8] 中国国家标准化管理委员会. 在非旋转部件上测量和评价机器的机械振动,第6部分:功率大于100KW的往复式机器, GB/T 6075.6-2002[S]. 北京:中国标准出版社,2012:6.Standardization Administration of the People’s Republic of China. Mechanical vibration evaluation of machine vibration by measurements on non-rotating parts, Part 6: Reciprocating machines with power ratings above 100kW, GB/T 6075.6-2002[S]. Beijing: Standards Press of China,2012: 6(In Chinese).
[9] The International Organization for Standardization. Reciprocating internal combustion engine driven alternating current generating sets, Part 9: Measurement and evaluation of mechanical vibrations, ISO 8528-9:1995 [S]. Switzerland, 2002: 10.
[10] 骆旭薇,石勇,李斌,等. 应用FEA-CFD耦合方法对某增压柴油机排气歧管的开裂失效分析及设计改进[J]. 内燃机工程, 2015, 36(6): 144-150.LUO XuWei, SHI Yong, LI Bin, et al. An FEA-CFD coupled analysis on the crack failure of the exhaust manifold of a turbo-charged diesel engine and design optimization[J]. Chinese Internal Combustion Engine Engineering, 2015, 36(6): 144-150(In Chinese).
[11] Eichlseder W. Rechnerische Lebensdaueranalyse von Nutzfahrzeugkomponenten mit der finite elemente method[D]. Dissertation, University of Technology Graz, Austria, 1989.
[12] Erwin Haibach. FKM Guideline: Analytical Strength Assessment of Components in Mechanical Engineering[M]. Frankfurt: VDMA, 2003: 125-131.
[13] Sean A. Mckelvey, Yung-Li Lee, Mark E. Barkey. Stress-based uniaxial fatigue analysis using methods described in FKM-guideline[J]. Journal of Failure Analysis & Prevention, 2012, 12(5): 445-484.
[14] Forschungskuratorium Maschinenbau e.V.: Festigkeitsnachweis, Project NO.154, Guideline[R]. Issue 183-2, 1994.
[2] 李松波,袁明,管西强,等. 轿车排气系统一维数值模型简化及模态实验验证[J]. 机械强度, 2009, 31(05): 731-735.LI SongBo, YUAN Ming, GUAN XiQiang, et al. One dimension numerical model simplification of exhaust system and vibration by modal experiment[J]. Journal of Mechanical Strength, 2009, 31(5): 731-735(In Chinese).
[3] 邢素芳,王现荣,王超,等. 发动机排气系统振动分析[J]. 河北工业大学学报, 2005, 34(5): 109-111.XING SuFang, WANG XianRong, WANG Chao, et al. Vibration analysis of engine exhaust system[J]. Journal of Hebei University of Technology, 2005, 34(5): 109-111(In Chinese).
[4] 马子远,毕玉华,申立中,等. 排气管热负荷结构影响因素分析[J]. 机械强度, 2016, 38(02): 348-355.MA ZiYuan, BI YuHua, SHEN LiZhong, et al. Study on structure influence factor of diesel engine exhaust manifold thermal load[J]. Journal of Mechanical Strength, 2016, 38(2): 348-355(In Chinese).
[5] 袁守利,王超,刘志恩,等. 高镍铸铁排气歧管低周热疲劳研究[J]. 武汉理工大学学报, 2014, 36(2): 190-202.YUAN ShouLi, WANG Chao, LIU ZhiEn, et al. Low cycle thermal fatigue of high nickel cast iron exhaust manifold[J]. Journal of WUT (Information & Management Engineering), 2014, 36(2): 190-202(In Chinese).
[6] 谭光辉,李秋彦,邓俊. 热环境下结构固有振动特性试验及分析[J]. 航空学报, 2016,37(1): 32-37.TAN GuangHui, LI QiuYan, DENG Jun. Test and analysis of natural modal characteristics of a wing model with thermal Effect[J]. Acta Aeronautica ET Astronautica Sinica, 2016, 37(1): 32-37(In Chinese).
[7] 中华人民共和国工业和信息部. 船用柴油机振动评级, CB/T 3256-2013[S]. 北京:中国船舶工业综合技术经济研究院出版社,2014:9.The Ministry of Industry and Information Technology of the People’s Republic of China. The evaluation of vibration on marine diesel engine, CB/T 3256-2013[S]. Beijing: China Institute of Marine Technology and Economy, 2014: 9(In Chinese).
[8] 中国国家标准化管理委员会. 在非旋转部件上测量和评价机器的机械振动,第6部分:功率大于100KW的往复式机器, GB/T 6075.6-2002[S]. 北京:中国标准出版社,2012:6.Standardization Administration of the People’s Republic of China. Mechanical vibration evaluation of machine vibration by measurements on non-rotating parts, Part 6: Reciprocating machines with power ratings above 100kW, GB/T 6075.6-2002[S]. Beijing: Standards Press of China,2012: 6(In Chinese).
[9] The International Organization for Standardization. Reciprocating internal combustion engine driven alternating current generating sets, Part 9: Measurement and evaluation of mechanical vibrations, ISO 8528-9:1995 [S]. Switzerland, 2002: 10.
[10] 骆旭薇,石勇,李斌,等. 应用FEA-CFD耦合方法对某增压柴油机排气歧管的开裂失效分析及设计改进[J]. 内燃机工程, 2015, 36(6): 144-150.LUO XuWei, SHI Yong, LI Bin, et al. An FEA-CFD coupled analysis on the crack failure of the exhaust manifold of a turbo-charged diesel engine and design optimization[J]. Chinese Internal Combustion Engine Engineering, 2015, 36(6): 144-150(In Chinese).
[11] Eichlseder W. Rechnerische Lebensdaueranalyse von Nutzfahrzeugkomponenten mit der finite elemente method[D]. Dissertation, University of Technology Graz, Austria, 1989.
[12] Erwin Haibach. FKM Guideline: Analytical Strength Assessment of Components in Mechanical Engineering[M]. Frankfurt: VDMA, 2003: 125-131.
[13] Sean A. Mckelvey, Yung-Li Lee, Mark E. Barkey. Stress-based uniaxial fatigue analysis using methods described in FKM-guideline[J]. Journal of Failure Analysis & Prevention, 2012, 12(5): 445-484.
[14] Forschungskuratorium Maschinenbau e.V.: Festigkeitsnachweis, Project NO.154, Guideline[R]. Issue 183-2, 1994.