冶金桥式起重机静动态特性和疲劳寿命分析

发布时间：2018-06-28 09:05

本文选题：冶金桥式起重机 + 有限元分析　；参考：《武汉科技大学》2011年硕士论文

【摘要】：随着钢铁行业的迅速发展,冶金专用起重机的需求越来越大,对其结构和性能要求也越来越高。冶金桥式起重机是钢铁厂最主要的设备之一,在其频繁地使用过程中,其结构强度、疲劳强度和可靠性水平均随着使用年限的增加而降低。特别是,在循环的交变动载荷的作用下,起重机的金属结构可能出现裂纹并发生扩展,最终导致起重机的金属结构的突然断裂破坏。当前,我国对起重机的报废年限还缺乏强制性的标准,且冶金专用起重机的造价较高,许多起重机已经达到甚至超过了设计使用年限,却仍然还在使用,造成了很大的安全隐患。因此,对服役周期长、负荷量大和使用频率高的冶金桥式起重机进行应力测试、静态特性、动态特性和疲劳寿命分析,显得十分必要。如果采用传统的力学计算方法对起重机进行研究,往往需要简化或估计相关参数,势必造成计算结果的不准确。为此,本文应用ANSYS有限元分析软件对200t×20m冶金桥式起重机的桥架结构的静态特性、动态特性(模态分析、谐响应分析和瞬态分析)和疲劳寿命特性进行模拟仿真与分析,以期为起重机的设计、制造、检验和管理提供有益的参考。通过对起重机桥架结构进行现场测试和静态特性分析,对桥架结构的应力分布状态有了全面的了解,获得了桥架结构的危险部位的应力水平和静刚度等指标。通过对起重机桥架结构进行动态特性分析,编写了模态分析、谐响应分析和瞬态分析的ANSYS参数化设计语言(ANSYS Parameter Design Language,APDL)。通过模态分析,提取了起重机前10阶固有频率及其所对应的振型图,并进行了动刚度校核;通过谐响应分析,分析了起重机在受外界激励作用时各阶频率下的变形情况;通过瞬态分析,获得了起重机的小车在桥架跨中位置起吊钢包时的动力响应,包括桥架(主梁)结构跨中部位的Y向位移、Y向速度和Y向加速度的时间历程曲线。应用有限元分析、损伤容限设计和断裂力学对起重机进行了疲劳寿命分析。根据Paris公式计算了起重机北主梁下盖板的跨中部位的疲劳寿命,并讨论了Paris公式中参数的改变对起重机疲劳寿命的影响。
[Abstract]:With the rapid development of iron and steel industry, the demand of metallurgical crane is increasing, and the requirements of its structure and performance are higher and higher. Metallurgical bridge crane is one of the most important equipment in iron and steel plant. During its frequent use, its structural strength, fatigue strength and reliability level decrease with the increase of service life. In particular, under the action of cyclic variable load, the metal structure of the crane may appear cracks and expand, and finally lead to the sudden fracture of the metal structure of the crane. Therefore, it is necessary to test the stress, static characteristics, dynamic characteristics and fatigue life of metallurgical bridge crane with long service cycle, high load and high frequency. If the traditional mechanical calculation method is used to study the crane, it is often necessary to simplify or estimate the relevant parameters, which will lead to the inaccuracy of the calculation results. In this paper, the static characteristics, dynamic characteristics (modal analysis, harmonic response analysis and transient analysis) and fatigue life characteristics of 200t 脳 20m metallurgical bridge crane are simulated and analyzed by ANSYS finite element analysis software. Through the field test and static characteristic analysis of the crane bridge structure, the stress distribution state of the bridge frame structure is fully understood, and the stress level and static stiffness of the dangerous part of the bridge frame structure are obtained. By analyzing the dynamic characteristics of crane bridge structure, the ANSYS Parameter Design language (ANSYS Parameter Design language APDL) is developed for modal analysis, harmonic response analysis and transient analysis. Through modal analysis, the first 10 natural frequencies of the crane and their corresponding mode shapes are extracted, and the dynamic stiffness check is carried out, and the deformation of the crane under external excitation is analyzed by harmonic response analysis. Through transient analysis, the dynamic response of the crane trolley to the ladle hoisting at the mid-span position of the bridge frame is obtained, including the time history curves of the Y-direction displacement and the Y-direction acceleration of the midspan of the bridge (main girder) structure. The fatigue life of crane was analyzed by finite element analysis, damage tolerance design and fracture mechanics. According to Paris formula, the fatigue life of the middle span of the lower cover plate of the north main girder of crane is calculated, and the influence of the parameters in Paris formula on the crane fatigue life is discussed.
【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH215

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