液压挖掘机工作装置的有限元分析及疲劳寿命预测
|
摘要
液压挖掘机是工程机械领域中一种典型的土石方施工机械,在工业与民用建筑、道路建设、农田水利、油田矿由、市政工程、机场港口等部门的土石方施工中起到十分重要的作用。挖掘机在挖掘过程中负载变化剧烈,而其工作装置作为挖掘机完成各项动作的直接实施者,承受着各种各样恶劣工况下载荷的作用,因此挖掘机工作装置的强度、可靠性和耐久性直接关系到挖掘机的工作性能和工作效率,对工作装置的强度及可靠性研究也具有非常重要的意义。
本文以某6吨小型挖掘机工作装置为研究对象,利用有限元软件Ansys对挖掘机工作装置进行了整体有限元分析。分析过程中,为使得分析结果更接近实际,将各铰接点处理为接触对,并对液压缸中的液压油进行了实体建模,将油液的相关参数赋予该实体,来模拟固液耦合对其性能的影响。同时利用应变测试系统测得工作装置各个测点的载荷-时间历程,经过分析处理,估算出各个测点的疲劳寿命。具体研究过程如下：
(1)通过分析挖掘对象的特点和挖掘机挖掘时的切削动作,以及考虑实际工作条件下各种限制因素的制约,对挖掘机的挖掘阻力和整机理论挖掘力进行了系统分析,确定了挖掘机工作装置的6种典型工况,作为力学分析的主要姿态,并计算出了各种工况下的理论挖掘力。
(2)对挖掘机工作装置进行整体有限元分析和模态分析,确定出工作装置在相应工况下的应力集中和刚度薄弱部位,为工作装置的维修和改进提供参考依据。
(3)利用动态应变测试系统实测出挖掘机工作装置危险点的载荷历程,然后对载荷历程进行滤波、雨流计数统计后得到载荷历程中的各级循环应力,结合线性累积损伤理论和工作装置的S-N曲线,推导出各个危险点的疲劳寿命。
Hydraulic excavator is a typical construction engineering machinery, which is widely used in industrial production, civil construction, road construction, water conservancy, oil mining, public works, airport and port construction, and other departments of the earth. The load changed violently in the mining process, and excavator working device, which is the direct implementation to complete working, bears the harsh load in the bad conditions, so excavator working device's strength, reliability and durability is directly related to the excavator performance and efficiency. Therefore, the study of excavator working device's intensity and reliability has a very essential significance.
In this paper, a mini hydraulic excavator's working device is researched, which is analyzed using finite element software Ansys, based on the overall finite element analysis method. In order to make the analysis more realistic, the hinge point is treated as contact, and the hydraulic oil in the hydraulic cylinder build as solid model. The relevant parameters will be given to the oil entity, in order to simulate the influence of the solid-liquid coupling to its performance. At the same time, the load time history of each test point is measured using strain test system, and the fatigue life of each point is estimated after analyzing the test result. A specific course of the study is as follows:
(1) The excavator's digging resistance and theory excavating force are analyzed systematic through analyzing the characteristics of digging objects and excavator's digging action and considering the various constraints factors under actual operating conditions. The six typical conditions are determined as a major attitude of mechanical analysis, and the theoretical digging forces are calculated under various conditions.
(2) In order to make the analysis more realistic, the hinge point is treated as contact, and the hydraulic oil in the hydraulic cylinder build as solid model. The relevant parameters will be given to the oil entity, in order to simulate the influence of the solid-liquid coupling to its performance. Through the overall finite element analysis and modal analysis of the excavator's working devices, the weak parts of the stress concentration and stiffness are determined in the corresponding condition, which provide reference for the maintenance and improvement of the working device.
(3) By using the strain measurement system, the load histories of the weak parts are measured in the paper. The load histories are analyzed with rain-flow counting method, and the structural S-N curve is corrected based on the fatigue test data of the material. The fatigue life of every test point is estimated by using the nominal stress method, which achieves the goal of fatigue life prediction of the working mechanism. This method can also give reference for the similar mechanism.
本文以某6吨小型挖掘机工作装置为研究对象,利用有限元软件Ansys对挖掘机工作装置进行了整体有限元分析。分析过程中,为使得分析结果更接近实际,将各铰接点处理为接触对,并对液压缸中的液压油进行了实体建模,将油液的相关参数赋予该实体,来模拟固液耦合对其性能的影响。同时利用应变测试系统测得工作装置各个测点的载荷-时间历程,经过分析处理,估算出各个测点的疲劳寿命。具体研究过程如下：
(1)通过分析挖掘对象的特点和挖掘机挖掘时的切削动作,以及考虑实际工作条件下各种限制因素的制约,对挖掘机的挖掘阻力和整机理论挖掘力进行了系统分析,确定了挖掘机工作装置的6种典型工况,作为力学分析的主要姿态,并计算出了各种工况下的理论挖掘力。
(2)对挖掘机工作装置进行整体有限元分析和模态分析,确定出工作装置在相应工况下的应力集中和刚度薄弱部位,为工作装置的维修和改进提供参考依据。
(3)利用动态应变测试系统实测出挖掘机工作装置危险点的载荷历程,然后对载荷历程进行滤波、雨流计数统计后得到载荷历程中的各级循环应力,结合线性累积损伤理论和工作装置的S-N曲线,推导出各个危险点的疲劳寿命。
Hydraulic excavator is a typical construction engineering machinery, which is widely used in industrial production, civil construction, road construction, water conservancy, oil mining, public works, airport and port construction, and other departments of the earth. The load changed violently in the mining process, and excavator working device, which is the direct implementation to complete working, bears the harsh load in the bad conditions, so excavator working device's strength, reliability and durability is directly related to the excavator performance and efficiency. Therefore, the study of excavator working device's intensity and reliability has a very essential significance.
In this paper, a mini hydraulic excavator's working device is researched, which is analyzed using finite element software Ansys, based on the overall finite element analysis method. In order to make the analysis more realistic, the hinge point is treated as contact, and the hydraulic oil in the hydraulic cylinder build as solid model. The relevant parameters will be given to the oil entity, in order to simulate the influence of the solid-liquid coupling to its performance. At the same time, the load time history of each test point is measured using strain test system, and the fatigue life of each point is estimated after analyzing the test result. A specific course of the study is as follows:
(1) The excavator's digging resistance and theory excavating force are analyzed systematic through analyzing the characteristics of digging objects and excavator's digging action and considering the various constraints factors under actual operating conditions. The six typical conditions are determined as a major attitude of mechanical analysis, and the theoretical digging forces are calculated under various conditions.
(2) In order to make the analysis more realistic, the hinge point is treated as contact, and the hydraulic oil in the hydraulic cylinder build as solid model. The relevant parameters will be given to the oil entity, in order to simulate the influence of the solid-liquid coupling to its performance. Through the overall finite element analysis and modal analysis of the excavator's working devices, the weak parts of the stress concentration and stiffness are determined in the corresponding condition, which provide reference for the maintenance and improvement of the working device.
(3) By using the strain measurement system, the load histories of the weak parts are measured in the paper. The load histories are analyzed with rain-flow counting method, and the structural S-N curve is corrected based on the fatigue test data of the material. The fatigue life of every test point is estimated by using the nominal stress method, which achieves the goal of fatigue life prediction of the working mechanism. This method can also give reference for the similar mechanism.
引文
[1]同济大学.单斗液压挖掘机[M].第二版,中国建筑工业出版社,1986.12.
[2]姬鹏.液压挖掘机反铲装置的运动学仿真及动力学分析[D].吉林长春：吉林大学,2005.4.
[3]杜文靖.液压挖掘机工作装置设计关键技术研究[D].吉林长春：吉林大学,2007.3.
[4]李兵,何正嘉,陈雪峰ANSYS Workbench设计、仿真与优化[M].清华大学出版社,2009.9.
[5]周传月,郑红霞,罗惠强等. MSC.Fatigue疲劳分析应用于教程[M].科学出版社,2005.3.
[6]王国军. MSC.Fatigue疲劳分析实例指导教程[M].机械工业出版社,2009.1.
[7]冯国平.机械式挖掘机的动力学分析与智能化设计[D].辽宁沈阳：东北大学,2006.1.
[8]张卧波,杨俊峰,王建明,张强.挖掘机工作及运动状态的仿真与应用研究[J].农业工程学报,2008,24(2)：149-151.
[9]陈玉峰.液压挖掘机工作装置运动与动力综合优化研究[D].重庆：重庆大学,2005.5.
[10]孙志广.液压挖掘机工作装置优化设计及性能仿真[D].吉林长春：吉林大学2005.10.
[11]Pyung Hun Chang, Lee, S.J. A straight-line motion tracking control of hydraulic excavator system [J]. Mechatronics,2002,12(1):119-138.
[12]Frimpong S, Li Y. Virtual prototype simulation of hydraulic shovel kinematics for spatial characterization in surface mining operations [J]. International Journal of Surface Mining, Reclamation and Environment,2005,19(4):238-250.
[13]Imanishi Etsujiro, Nanjo Takao, Hiroka, etc. Dynamic simulation of flexible multibody system with the hydraulic drive [J]. Nippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C,2003,69(9): 2336-2343.
[14]Emil Assenov, E.Bosilkov, Radoslav Dimitrov, Tzvetan Damianov. Kinematics and dynamics of working mechanism of hydraulic excavator [J]. Mechanization, Electrification and Automation in Mines,2003,46(3):47-49.
[15]郑家坤.基于虚拟样机的挖掘机工作装置的设计与仿真[D].四川成都：西南交通大学,2008.4.
[16]Samuel Frimpong, Yafei Hu, Hilary Inyang. Dynamic Modeling of Hydraulic Shovel Excavators for Geo-materials[J]. International Journal of Geo-mechanics,2008,8(1): 20-29.
[17]邓子龙,高财禄,付越.挖掘机铲斗强度分析[J].辽宁石油化工大学学报,2007,27(4)：45-50.
[18]史青录,张福生,连晋毅.挖掘机动臂强度对比分析[J].工程机械,2009,40(7)：40-43.
[19]Feng Suli, Tian zhigang, Zhai Xuhua, Zhang Guangyu, Li Yan. Optimization of the Top Guard for Excavator Based on Neural Genetic Algorithm [J]. International Conference on Intelligent Computation Technology and Automation,2008:1240-1243.
[20]王创民.WK-10型挖掘机斗杆有限元强度分析[J].机械工程与自动化,2008,6(12)：71-72,75.
[21]Kosugi A, Kohmoto T, Taji T. Hydraulic Excavator Boom And Arm Strength Evaluation Method [J]. R&D, Research and Development(Kobe Steel, Ltd),1981,31(2):71-76.
[22]潘双夏,刘静,冯培恩.基于虚拟样机的挖掘机器人轨迹规划[J].中国机械工程,2005,16(21)：1926-1930.
[23]史晓晨.挖掘机轨迹智能控制系统的研究与开发[D].辽宁沈阳：东北大学,2006.1.
[24]Hall A.S., McAree P.R. Robust bucket position tracking for a large hydraulic excavator [J]. Mechanism and Machine Theory,2005,40(1):1-16.
[25]Takashi, Hiroshi. Motion Analysis of Hydraulic Excavator in Excavating and Loading Work for Autonomous Control [J]. International Symposium on Automation and Robotics in Construction,2006.
[26]Yuki, Daisuke, Hiroshi, Hajime. The Analysis of Excavator Operation by Skillful Operator [J]. SICE Annual Conference,2008.
[27]李渊博.基于Windows CE的挖掘机器人轨迹规划研究[D].湖南长沙：中南大学,2006.4.
[28]丛楠.军用工程机械虚拟疲劳试验研究[D].湖南长沙：国防科学技术大学,2006.11.
[29]苏猛,张万山.液压挖掘机工作装置断裂分析[J].煤矿机械,2006,27(6)：975-976.
[30]John E. Pearson, W. Robert Hannen, Erik Soderberg. Development of Fatigue Monitoring System for a Hydraulic Excavator [J]. Practice periodical on structural design and construction,2004:221-226.
[31]陈玉峰,宋立权,韩文强.液压挖掘机工作装置运动与动力综合优化[J].建筑机械,2005,(2)：80-82.
[32]潘玉安,程洪涛,姜迪友.基于ADAMS的挖掘机工作装置的仿真与优化设计[J].煤矿机械,2009,30(3)：15-17.
[33]Durkovit Radan, Bulatovic Ranislav. Modeling and optimization of the working mechanism motion of the hydraulic excavator [J]. Modelling, Simulation & Control B: Mechanical & Thermal Engineering, Materials & Resources, Chemistry,1990,30(3): 23-32.
[34]薛渊,吕光明,陆念力.复合形法在液压挖掘机铲斗连杆机构优化设计中的应用[J].现代制造工程,2006(2)：114-116.
[35]孔德文,赵克利,徐宁生.液压挖掘机[M].化学工业出版社,2009,4.
[36]任友良.液压挖掘机工作装置结构性能分析[D].浙江杭州：浙江大学,2010,1.
[37]郭克刚.挖掘机工作装置变量化3D建模与CAD研究[D].山西太原：太原科技大学,2008,7.
[38]9141-88液压挖掘机结构强度试验方法[S].北京：国家标准局,1988.
[39]杜文靖,崔国华,李小光.液压挖掘机工作装置整体集成有限元分析[J].农业机械学报,2007,38(10)：19-23.
[40]张智勇,沈荣瀛,王强.充液管道系统的模态分析[J].固体力学学报,2001,22(2)：143-149.
[41]ANSYS Workbench help document. Release 11.0 Documentation for ANSYS Workbench.
[42]熊诗波,黄长艺.机械工程测试技术基础(第3版)[M].北京：机械工业出版社,2006.6.
[43]刘义伦.工程构件疲劳寿命预测理论与方法[M].长沙：湖南科学技术出版社,1997.6.
[44]姚卫星.结构疲劳寿命分析[M].北京：国防工业出版社,2003.1.
[45]赵少汴,王忠保.疲劳设计[M].北京：机械工业出版社,1992.5.
[46]毛文刚,张一辉,王德禹.基于Matlabl的现役港口起重机剩余寿命估算[J].机械设 计与制造,2005,(11)：1-3.
[47]赵晓鹏,姜丁,张强.雨流计数法在整车载荷谱分析中的应用[J].科技导报,2009,27(3)：67-73.
[48]周俊,童小燕.雨流计数的快速实现方法[J].科学技术与工程,2008,8(13)：3544-3547.
[49]Andrea Carpinteri, Andrea Spagnoli. Size effect in S-N curves:A fractal approach to finite-life fatigue strength [J]. International Journal of Fatigue,2009(31):927-933.
[50]Glinka G. Calculation of Inelastic Notch-tip Strain Stress Histories under Cyclic Loading. Engineering Fracture Mechanics [J].1985,22:839-854.
[2]姬鹏.液压挖掘机反铲装置的运动学仿真及动力学分析[D].吉林长春：吉林大学,2005.4.
[3]杜文靖.液压挖掘机工作装置设计关键技术研究[D].吉林长春：吉林大学,2007.3.
[4]李兵,何正嘉,陈雪峰ANSYS Workbench设计、仿真与优化[M].清华大学出版社,2009.9.
[5]周传月,郑红霞,罗惠强等. MSC.Fatigue疲劳分析应用于教程[M].科学出版社,2005.3.
[6]王国军. MSC.Fatigue疲劳分析实例指导教程[M].机械工业出版社,2009.1.
[7]冯国平.机械式挖掘机的动力学分析与智能化设计[D].辽宁沈阳：东北大学,2006.1.
[8]张卧波,杨俊峰,王建明,张强.挖掘机工作及运动状态的仿真与应用研究[J].农业工程学报,2008,24(2)：149-151.
[9]陈玉峰.液压挖掘机工作装置运动与动力综合优化研究[D].重庆：重庆大学,2005.5.
[10]孙志广.液压挖掘机工作装置优化设计及性能仿真[D].吉林长春：吉林大学2005.10.
[11]Pyung Hun Chang, Lee, S.J. A straight-line motion tracking control of hydraulic excavator system [J]. Mechatronics,2002,12(1):119-138.
[12]Frimpong S, Li Y. Virtual prototype simulation of hydraulic shovel kinematics for spatial characterization in surface mining operations [J]. International Journal of Surface Mining, Reclamation and Environment,2005,19(4):238-250.
[13]Imanishi Etsujiro, Nanjo Takao, Hiroka, etc. Dynamic simulation of flexible multibody system with the hydraulic drive [J]. Nippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C,2003,69(9): 2336-2343.
[14]Emil Assenov, E.Bosilkov, Radoslav Dimitrov, Tzvetan Damianov. Kinematics and dynamics of working mechanism of hydraulic excavator [J]. Mechanization, Electrification and Automation in Mines,2003,46(3):47-49.
[15]郑家坤.基于虚拟样机的挖掘机工作装置的设计与仿真[D].四川成都：西南交通大学,2008.4.
[16]Samuel Frimpong, Yafei Hu, Hilary Inyang. Dynamic Modeling of Hydraulic Shovel Excavators for Geo-materials[J]. International Journal of Geo-mechanics,2008,8(1): 20-29.
[17]邓子龙,高财禄,付越.挖掘机铲斗强度分析[J].辽宁石油化工大学学报,2007,27(4)：45-50.
[18]史青录,张福生,连晋毅.挖掘机动臂强度对比分析[J].工程机械,2009,40(7)：40-43.
[19]Feng Suli, Tian zhigang, Zhai Xuhua, Zhang Guangyu, Li Yan. Optimization of the Top Guard for Excavator Based on Neural Genetic Algorithm [J]. International Conference on Intelligent Computation Technology and Automation,2008:1240-1243.
[20]王创民.WK-10型挖掘机斗杆有限元强度分析[J].机械工程与自动化,2008,6(12)：71-72,75.
[21]Kosugi A, Kohmoto T, Taji T. Hydraulic Excavator Boom And Arm Strength Evaluation Method [J]. R&D, Research and Development(Kobe Steel, Ltd),1981,31(2):71-76.
[22]潘双夏,刘静,冯培恩.基于虚拟样机的挖掘机器人轨迹规划[J].中国机械工程,2005,16(21)：1926-1930.
[23]史晓晨.挖掘机轨迹智能控制系统的研究与开发[D].辽宁沈阳：东北大学,2006.1.
[24]Hall A.S., McAree P.R. Robust bucket position tracking for a large hydraulic excavator [J]. Mechanism and Machine Theory,2005,40(1):1-16.
[25]Takashi, Hiroshi. Motion Analysis of Hydraulic Excavator in Excavating and Loading Work for Autonomous Control [J]. International Symposium on Automation and Robotics in Construction,2006.
[26]Yuki, Daisuke, Hiroshi, Hajime. The Analysis of Excavator Operation by Skillful Operator [J]. SICE Annual Conference,2008.
[27]李渊博.基于Windows CE的挖掘机器人轨迹规划研究[D].湖南长沙：中南大学,2006.4.
[28]丛楠.军用工程机械虚拟疲劳试验研究[D].湖南长沙：国防科学技术大学,2006.11.
[29]苏猛,张万山.液压挖掘机工作装置断裂分析[J].煤矿机械,2006,27(6)：975-976.
[30]John E. Pearson, W. Robert Hannen, Erik Soderberg. Development of Fatigue Monitoring System for a Hydraulic Excavator [J]. Practice periodical on structural design and construction,2004:221-226.
[31]陈玉峰,宋立权,韩文强.液压挖掘机工作装置运动与动力综合优化[J].建筑机械,2005,(2)：80-82.
[32]潘玉安,程洪涛,姜迪友.基于ADAMS的挖掘机工作装置的仿真与优化设计[J].煤矿机械,2009,30(3)：15-17.
[33]Durkovit Radan, Bulatovic Ranislav. Modeling and optimization of the working mechanism motion of the hydraulic excavator [J]. Modelling, Simulation & Control B: Mechanical & Thermal Engineering, Materials & Resources, Chemistry,1990,30(3): 23-32.
[34]薛渊,吕光明,陆念力.复合形法在液压挖掘机铲斗连杆机构优化设计中的应用[J].现代制造工程,2006(2)：114-116.
[35]孔德文,赵克利,徐宁生.液压挖掘机[M].化学工业出版社,2009,4.
[36]任友良.液压挖掘机工作装置结构性能分析[D].浙江杭州：浙江大学,2010,1.
[37]郭克刚.挖掘机工作装置变量化3D建模与CAD研究[D].山西太原：太原科技大学,2008,7.
[38]9141-88液压挖掘机结构强度试验方法[S].北京：国家标准局,1988.
[39]杜文靖,崔国华,李小光.液压挖掘机工作装置整体集成有限元分析[J].农业机械学报,2007,38(10)：19-23.
[40]张智勇,沈荣瀛,王强.充液管道系统的模态分析[J].固体力学学报,2001,22(2)：143-149.
[41]ANSYS Workbench help document. Release 11.0 Documentation for ANSYS Workbench.
[42]熊诗波,黄长艺.机械工程测试技术基础(第3版)[M].北京：机械工业出版社,2006.6.
[43]刘义伦.工程构件疲劳寿命预测理论与方法[M].长沙：湖南科学技术出版社,1997.6.
[44]姚卫星.结构疲劳寿命分析[M].北京：国防工业出版社,2003.1.
[45]赵少汴,王忠保.疲劳设计[M].北京：机械工业出版社,1992.5.
[46]毛文刚,张一辉,王德禹.基于Matlabl的现役港口起重机剩余寿命估算[J].机械设 计与制造,2005,(11)：1-3.
[47]赵晓鹏,姜丁,张强.雨流计数法在整车载荷谱分析中的应用[J].科技导报,2009,27(3)：67-73.
[48]周俊,童小燕.雨流计数的快速实现方法[J].科学技术与工程,2008,8(13)：3544-3547.
[49]Andrea Carpinteri, Andrea Spagnoli. Size effect in S-N curves:A fractal approach to finite-life fatigue strength [J]. International Journal of Fatigue,2009(31):927-933.
[50]Glinka G. Calculation of Inelastic Notch-tip Strain Stress Histories under Cyclic Loading. Engineering Fracture Mechanics [J].1985,22:839-854.