通用桥式起重机金属结构设计验证及安全评价

发布时间：2018-01-02 22:15

本文关键词：通用桥式起重机金属结构设计验证及安全评价　出处：《太原科技大学》2011年硕士论文　论文类型：学位论文

【摘要】：通用桥式起重机金属结构设计的方法,长期以来采用许用应力法。许用应力法以单一的安全系数来衡量金属结构承受的载荷、材料的不确定性,无论从结构设计理论还是实际计算当中,此种方法都有缺点。起重机金属结构是起重机械的“骨骼”,是主要的承载部件。为了保证结构在规定的使用寿命期间内,实现各种规定的功能,研究一种适合起重机结构的设计方法是至关重要的。我国最新颁布的《GB/T3811-2008起重机设计规范》[5]引入了极限状态法,极限状态法以概率论和数理统计为基础用分项系数代替安全系数,充分考虑了载荷和材料的不确定性。从许用应力法设计转向极限状态法设计,使结构的设计由定值法过渡到概率法。根据国家质量监督检验总局的报告,由起重机结构引发的事故不断,且呈连年上升的态势。这些事故给国家的基础建设和人员带来了巨大的损失。如何有效的减少这类事故的发生是设计人员面临的重大问题。通过国内外专家的研究发现,若能在事故发生前对结构进行科学有效的安全评价,找出结构存在的风险因素和安全隐患并及时采取措施,可有效的减少事故的发生。国内对起重机金属结构的安全评价处于初期阶段,主要采用故障类型影响分析法、事故树分析法和层次分析法等传统方法。这些方法在统计上简单易行,但对事故的分析过于简单。随着生物学和计算机技术的进步,人工神经网络得到了飞速的发展,本文首次把BP神经网络应用到通用桥式起重机金属结构的安全评价当中,基于BP网络的理论建立了起重机金属结构安全评价模型,并结合层次分析法建立了通用桥机金属结构的安全评价指标体系。根据BP网络的自组织、自学习和高度并行性的特点,用搜集的样本对BP网络进行训练。运用Matlab7.0软件编制相应的程序,通过对BP网络的验证,安全评价结果与期望结果误差较小,网络的收敛性较好和误差精度较高,完全满足起重机结构安全评价的需求。本文以Visual C++6.0为开发平台,开发出“通用桥式起重机结构极限状态设计方法设计验证技术系统”,通过工程实例的验证,系统的验证结果与实际计算结果基本一致,并且由极限状态法得出的结果比许用应力法偏大,使结构的设计裕度更大和更加经济合理。
[Abstract]:A method for designing the metal structure of a universal bridge crane has been adopted for a long time . The allowable stress method has been used to measure the load and the uncertainty of the metal structure . The metal structure of the crane is the main bearing part . In order to ensure the structure to realize the functions of various regulations during the specified service life , it is very important to study a design method suitable for the crane structure . In order to ensure the structure to realize various specified functions during the specified service life , the limit state method is designed to use the probability theory and the mathematical statistics to replace the safety factor , and the design of the steering limit state method is designed from the allowable stress method , so that the design of the structure is transferred to the probability method by the fixed value method . According to the report of the State Administration of Quality Supervision and Inspection , the accidents caused by the crane structure are continuously and continuously rising . These accidents bring huge losses to the basic construction and personnel of the country . How to reduce the accidents effectively is the major problem that the designers face . Through the research of experts at home and abroad , it is found that if the structure is scientifically and effectively evaluated before the accident happens , the risk factors and potential safety hazards of the structure are found and the measures are taken in a timely manner , so that the occurrence of accidents can be effectively reduced . The safety evaluation of the metal structure of crane is in the early stage , and the traditional methods such as fault type influence analysis method , accident tree analysis method and analytic hierarchy process are adopted . The safety evaluation model of crane metal structure is established based on BP neural network . Based on the development platform of Visual C ++ 6.0 , the design verification technical system of the design method of the general bridge crane structure limit state is developed . Through the verification of the engineering example , the verification result of the system is basically consistent with the actual calculation result , and the result obtained by the limit state method is larger than the allowable stress method , so that the design margin of the structure is larger and more economical and reasonable .

【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH215

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