【作者】 薛继忠；

【导师】 易传云；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2005， 硕士

【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。更多还原

【Abstract】 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.更多还原