超高压管式反应器端部结构应力场的研究
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摘要
超高压管式反应器是管式超高压聚乙烯装置的关键设备,其端部通常为夹套与反应管的过盈配合连接结构。利用电阻应变测量技术,针对某石化厂发生疲劳断裂的超高压管式反应器端部结构应力场开展试验研究,采用应力释放法获得过盈配合后的局部应力场数据,在此基础上,建立基于ANSYS软件的有限元模型,并与试验数据进行对比分析。结果表明,端部结构的过盈配合边缘局部范围内存在较高的轴向拉应力,且大于环向应力,应力水平随过盈量增加而提高;接触刚度对应力场数值模拟结果影响较大,在保证收敛的前提下应尽量增大接触刚度以提高模拟精度,有限元模拟结果与试验数据符合得较好。研究结果对后期的数值模拟以及结构失效原因的分析提供重要参考依据。
Ultrahigh pressure tubular reactor is the key equipment of tube-type ultrahigh pressure polyethylene, its end is usually the shrink-fit structure composed of jacket and reaction tube. Stress field of end structure of the ultrahigh pressure polyethylene tubular reactor, in which fatigue fracture occurred, is experimentally studied by measuring electric resistance strain. And the local stress field after shrink-fit is obtained based on stress release method. In terms of experimental results, ANSYS FEM is built and the simulation results compared with experimental data. The results show that a large tensile axial stress appeared on the location at the edge of the shrink-fit and it's larger than hoop stress, and the local stress level increases with the increase of shrink-fit range; the influence of contact stiffness on simulation results is significant, and in order to improve the simulation accuracy, the combination of contact stiffness and convergence has to be optimized; the FEM simulation results is consistent well with the experimental data. The study results can provide some insight into subsequent numerical simulation and failure analysis of the end structure.
Ultrahigh pressure tubular reactor is the key equipment of tube-type ultrahigh pressure polyethylene, its end is usually the shrink-fit structure composed of jacket and reaction tube. Stress field of end structure of the ultrahigh pressure polyethylene tubular reactor, in which fatigue fracture occurred, is experimentally studied by measuring electric resistance strain. And the local stress field after shrink-fit is obtained based on stress release method. In terms of experimental results, ANSYS FEM is built and the simulation results compared with experimental data. The results show that a large tensile axial stress appeared on the location at the edge of the shrink-fit and it's larger than hoop stress, and the local stress level increases with the increase of shrink-fit range; the influence of contact stiffness on simulation results is significant, and in order to improve the simulation accuracy, the combination of contact stiffness and convergence has to be optimized; the FEM simulation results is consistent well with the experimental data. The study results can provide some insight into subsequent numerical simulation and failure analysis of the end structure.
引文
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[14]余伟炜,高炳军.ANSYS在机械与化工装备中的应用[M].北京:中国水利水电出版社,2007.YU Weiwei,GAO Bingjun.Applications of ANSYS in mechanical and chemical equipment[M].Beijing:China Water Power Press,2007.
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[16]张建军,王晓慧,王守信.工程接触问题的罚优化方法与罚因子的选取[J].河北工业大学学报,1999,28(6):76-80.ZHANG Jianjun,WANG Xiaohui,WANG Shouxin.A penalty optimized method of contact problem in engineering and selection of penalty factor[J].Journal of Hebei University of Technology,1999,28(6):76-80.
[2]刘伟,何建暖.基于CFD的高压聚乙烯反应器腐蚀失效机理研究[J].石油化工设备,2011,40(3):11-14.LIU Wei,HE Jiannuan.Analysis based on computational flow dynamics method on failure mechanism of high-pressure polythene reactor[J].Petro-Chemical Equipment,2011,40(3):11-14.
[3]刘康林.超高压聚乙烯反应管安全评定[J].石油化工设备,2001,30(6):1-4.LIU Kanglin.Safety assessment for ultrahigh pressure polyethylene reaction tube[J].Petro-Chemical Equipment,2001,30(6):1-4.
[4]关家锟,柳曾典,潘家桢,等.高压聚乙烯装置超高压管失效分析[J].中国锅炉压力容器安全,1997,13(6):22-25.GUAN Jiakun,LIU Zengdian,PAN Jiazhen,et al.Failure analysis for ultrahigh pressure tube of high-pressure polyethylene device[J].China Boiler and Pressure Vessel Safety,1997,13(6):22-25.
[5]李景胜,王罗贤,龚春欢,等.高压聚乙烯反应管泄漏原因分析[J].压力容器,1994,11(2):64-68.LI Jingsheng,WANG Luoxian,GONG Chunhuan,et al.Analysis of reason to leakage for high pressure polythene tubular reactor[J].Pressure Vessel Technology,1994,11(2):64-68.
[6]董美云,宋亚昕,魏延刚.机车轮对过盈配合温差法装配的有限元模拟[J].大连铁道学院学报,2003,24(4):21-24.DONG Meiyun,SONG Yaxin,WEI Yangang.FE simulations of interference fit joints of wheel and shaft in locomotive[J].Journal of Dalian Railway Institute,2003,24(4):21-24.
[7]曾飞,陈光雄,周仲荣.基于ANSYS的轮对过盈配合微动分析[J].机械工程学报,2011,47(5):121-125.ZENG Fei,CHEN Guangxiong,ZHOU Zhongrong.Fretting analysis of interference fitting of wheel-set based on ANSYS[J].Journal of Mechanical Engineering,2011,47(5):121-125.
[8]FREDERIC L,AURELIAN V,BERNARD S.Finite element analysis and contact modeling considerations of interference fits for fretting fatigue strength calculations[J].Simulation Modelling Practice and Theory,2009,17(10):1587-1602.
[9]WEI Yangang.Research on stress analysis and contacting edge for interference fit joint of hub[J].Journal of Machine Design,2004,21(1):36-39.
[10]杨广雪,谢基龙,李强,等.过盈配合微动损伤的关键参数[J].机械工程学报,2010,46(16):53-59.YANG Guangxue,XIE Jilong,LI Qiang,et al.Key parameters of fretting damage under shrink fit[J].Journal of Mechanical Engineering,2010,46(16):53-59.
[11]危书涛,陈学东,崔军,等.超高压管式反应器端部结构应力场的数值模拟[J].压力容器,2012,29(10):23-28.WEI Shutao,CHEN Xuedong,CUI Jun,et al.Numerical simulation of stress field of end structure of ultrahigh pressure tubular reactor[J].Pressure Vessel Technology,2012,29(10):23-28.
[12]张如一,陆耀桢.实验应力分析[M].北京:机械工业出版社,1988.ZHANG Ruyi,LU Yaozhen.Experimental stress analysis[M].Beijing:China Machine Press,1988.
[13]许小强,赵洪伦.过盈配合应力的接触非线性有限元分析[J].机械设计与研究,2000(1):33-35.XU Xiaoqiang,ZHAO Honglun.Nonlinear FEM analysis of the contact stress on interference fitting surfaces[J].Machine Design&Research,2000(1):33-35.
[14]余伟炜,高炳军.ANSYS在机械与化工装备中的应用[M].北京:中国水利水电出版社,2007.YU Weiwei,GAO Bingjun.Applications of ANSYS in mechanical and chemical equipment[M].Beijing:China Water Power Press,2007.
[15]UNDERHILL W R C,DOKAINISH M A,ORAVAS G E.A method for contact problems using virtual elements[J].Computer Methods in Applied Mechanics and Engineering,1997,143:229-247.
[16]张建军,王晓慧,王守信.工程接触问题的罚优化方法与罚因子的选取[J].河北工业大学学报,1999,28(6):76-80.ZHANG Jianjun,WANG Xiaohui,WANG Shouxin.A penalty optimized method of contact problem in engineering and selection of penalty factor[J].Journal of Hebei University of Technology,1999,28(6):76-80.