摘要
近10 多年来,在役桥式起重机桥架结构由于承载能力不足引起的坍塌事故时有发生,特别是近几年以来,我国在80 年代以前投产的桥式起重机相当一部分已经达到报废时限,但是出于生产成本的考虑,很大一部分起重机依然超期服役。为了保证其安全运行,为生产使用提供科学理论依据,本课题提出了以科学测试数据为基础,以结构可靠性为理论为依据的桥式起重机桥架结构承载能力综合、系统的评估方法。
本文首先模拟桥式起重机桥架结构的实际承载状况,建立了桥架的有限元力学模型,按最大载荷的工况组合对桥架进行了有限元仿真分析,得到了桥架的受载应力分布状况以及桥架结构的承载薄弱点。为了全面掌握桥式起重机桥架当前的实际承载状态,为承载能力可靠性评估提供科学数据,提出了着重考虑桥架结构承载薄弱点的承载能力测试方法,包括无损检测方案和载荷电测应力试验方法。
在有限元分析和承载能力测试的基础上,建立了基于常规可靠性理论的桥架结构承载能力可靠性评估模型,充分考虑影响桥架承载能力因素的随机性,按可靠性模型进行桥架承载能力可靠性指标计算,然后按评判准则进行承载能力评估,达到了量化评估的目的。为了方便在工程应用中使用本课题研究所提出的评估方法,编制了一套相应的承载能力可靠性评估程序。
此外,本文也将结构模糊随机可靠性理论应用到桥式起重机桥架结构的承载能力评估研究,同时考虑了影响桥架结构承载能力因素的随机性与模糊性,建立了基于模糊随机可靠性理论的承载能力评估模型。采用以工程实践和专家经验的方法确立隶属函数,进行模糊可靠性指标的计算,从而在基于模糊可靠性的桥架结构承载能力评估方法上作出了一定探讨性的研究。
最后,对本文所提出的桥式起重机桥架承载能力系统的评估方法做出了总结,并对将来的进一步研究作了分析和展望。
In the nearly 10 years, some collapse accidents occasionally happened due to bearing capacity deficiency of the bridge-crane structure in service. Especially in recent years, a great part of the bridge-cranes be produced before 1980’s are step into the stage of aging, but for reason of the cost, some of them are still in used as before. In order to evaluate the bearing capacity correctly for the sake of production safety, this paper developed a method based on the tested data and the theory of reliability to evaluate the bearing capacity of the bridge-crane structures.
The paper firstly simulates the real bearing conditions of the bridge-crane, and establishes the finite element analysis model of the crane structure, and get the stress distribution and the weak bearing capacity points of the bridge-crane structure. In order to fully get the real bearing conditions of bridge-crane and get the correct data for the bearing capacity reliability evaluation, develop a method on testing the bearing capacity of weak points of the bridge-crane structure, including the methods of no destruction test and stress test.
On the base of finite element analysis and testing on the bearing capacity, set up reliability evaluate model based on the bearing capacity of the bridge-crane structure. The model fully considers the random of the factors that affect the bearing capacity, and evaluate the bearing capacity in certain evaluate norms. In order to conveniently use the method in practice, developed a bearing capacity evaluation software.
Furthermore, this paper firstly put the theory of random and fuzzy reliability theory into the evaluate research of the bearing capacity of the bridge-cranes. Both consider the random and fuzzy factors of the bearing capability of the bridge-cranes, setup a evaluate model based on the above theory.
At the end, summarize the theory of the bearing capacity evaluation method for the bridge-crane structures, and foretell the advanced research.
引文
[1] 陈玮璋,起重机金属结构.第1 版.北京:人民交通出版社,1986 年.78~96
[2] Ayyub B M ,kaminskiy M P, moser D A.Reliability analysis and assessment of hydropower equipment.Washington, D C:IWR REPORT 98-R-6,US Army Corps of Engineers, 1998:1123~1137
[3] 张爱林,赵国藩,王光远.现役结构可靠性评定研究叙评.北京工业大学学报,1998,Vol.24,No.2 (6):130~135
[4] 赵国藩,李云贵.旧有结构性能评估.大连理工大学学报,1991,Vol.1,No.1 (11): 687~692
[5] 黄培文,徐斌.冶金铸造起重机桥架主梁使用安全评估.武汉冶金科技大学学报,1997,Vol.20,No.1(3):62~68
[6] 崔甲昌,何庆生,杨国静.桥式起重机钢结构可靠性分析.起重运输机械,1992(4):3~9
[7] Yao J T P.Safety and Reliability of Existing Structures.New York:Pitman Advanced Publishing Program, 1985:76~100
[8] 赵国藩.工程结构可靠性理论与应用.第1 版.大连:大连理工大学出版社,1996.
[9] P Martin.A review of mechanical reliability.Proc. Instn Mech.Engrs,1985,Vol212 Part E:281~287
[10] T.V.Micic,M.K.Chryssanthopoulos.Reliability analysis for highway Bridge deck assessment.Structural Safety,1995(17):135~150
[11] 张爱林,赵国藩,王光远.现役结构模糊可靠度评估实用方法.应用基础与科学学报,1998,Vol.6,No.1 (3):78~84
[12] 吴世伟.结构可靠性分析.第1 版.北京:人民交通出版社,1990 年.
[13] 陈道礼.一阶可靠性方法在桥吊箱型主梁可靠度估算中的应用.机械设计与制 造,1996,No.6 :18~24
[14] Hasofer AM, Lind N C.An exact and invariant second-moment code format.Journal of the Engineering Mechanics Division ASCE,1984,100(1):111~121
[15] Kiureghran A D.Second-order reliability approximation.Journal of Engineering Mechanics,1984,100(3):1208~1223
[16] 桂红斌,郭昌捷.二阶二次矩法在船舶结构可靠性分析中的应用.大连理工大学学报,1999,Vol.38,No.4(7):493~494
[17] A.Z. Keller,C.Kara-zartri.Further application of fuzzy logic to reliability assessment and safety analysis.Micro electron Reliab, 1989(29):399~404
[18] 王光远,刘玉彬.结构模糊随机可靠度的实用计算方法.地震工程与工程振动,1995,Vol.15,No.3(9):38~46
[19] 涂文戈,林丽川.结构的模糊可靠性分析.中南工业大学学报,2000,Vol.31, No.4(8):371~374
[20] 黄洪钟,孙占全.随机应力模糊强度时模糊可靠性的计算理论.机械强度,2001,No.23(3):305~307
[21] Dager. H.J.System reliability analysis of transmission lines.Engineering Structures, 1990,Vol.14,No.4:251~258
[22] Bruce R,Ellingwood.Realiblity-based condition assessment and LRFD for existing structure.Structure Safety,1996,Vol.18,No.6:67~80
[23] V.A.Kopnov.Fatigue life prediction of the metalwork of a traveling gantry crane.Engineering Failure Analysis,1999(6):131~141
[24] 李士灜,商伟军.具有初始挠度的薄壁箱形结构承载能力研究.港口装卸,1995(6):76~82
[25] Kiyohiro Imai.System reliability of suspension bridges.Structural Safety,2002(24):219~259
[26] Hartmut Pasternak.Crane load odelling.Structural Safety,1996 (17):205~224
[27] L. Cveticanin.Dynamic behavior of the lifting crane mechanism.Mech. Mach. Theory, 1995,Vol.30,No.1:141~151
[28] 王德昌,张富胜.无损探伤在起重机检测中的应用.起重运输机械,1995(8):30~31
[29] 杨新华.大吨位桥式起重机主梁静刚度检测方法.工业安全与防尘,1998(1):22~24
[30] 陶德馨,刘钢.港口起重机金属结构技术状态的检测、评定与分析.起重运输机械,1994(1):25~28
[31] R.J.Ditchburn,S.K.Burke,C.M Scala.NDT of welds,state of the art.NDT&E International,1996,Vol.29,No.2:111~117
[32] K.H 候伯纳.工程师用有限元素法.北京:机械工业出版社,1981.
[33] 博嘉科技.ANSYS 融会与贯通.北京:中国水利水电出版社,2002:7~23
[34] 起重机设计规范[S].GB 3811-83.北京:国家标准出版社,1984
[35] 起重机设计手册编写组.起重机设计手册[M].北京:机械工业出版社,1980.
[36] 祝爕权.实用金属材料手册[M].上海:上海科学技术出版社,1993:324
[37] 孙长虹.应变仪用于桥式起重机主梁强度检测.工业安全与防尘,1998(12):19~20
[38] 崔甲昌,何庆生,桥吊主梁静强度抗力变异性的初步研究.山西矿业学院学报,1991(12):386~393
[39] Dilip K Mahanty,Statish Lyer.Vikas Manohar,Design Evaluation of the 375T electric Overhead Traveling Crane.Mechanical Engineering Design,1997(12):1123~1130
[40] 汪培庄.模糊集合论及其应用.上海:上海科学技术出版社,1987.
[41] 陈胜军.模糊可靠度计算模型.机械科学与技术,1999(5):392~394
[42] 黄洪钟.结构强度的模糊可靠性分析.机械科学与技术,1994(2):1~5
[43] Xu.T,Bea.R.G.Reliablity evaluation of existing platforms based on fuzzy set theory.Proceeding of the Secong internation Offshore and Polar Engineering Conference,1992(6):14~19
[44] 杜小平.机械零件的模糊可靠性分析.机械,1994(6):31~34
[45] 顾冰芳,刘斌.机械零件模糊可靠性设计方法的研究.解放军理工大学学报,2001(4):70~73
[46] Jon Bates,TIM Tompkins.实用VC++6.0 教程.何建辉.北京:清华大学出版社,2000.32~38