梯形波纹腹板焊接梁疲劳性能研究

发布时间：2018-04-17 10:35

本文选题：梯形波纹腹板 + 疲劳评定　；参考：《武汉科技大学》2016年硕士论文

【摘要】：梯形波纹腹板焊接梁是一种新型梁结构,由于其一系列优越的力学特性,近年来得到较快的发展。梯形波纹腹板焊接梁大多采用焊接方式加工制造,疲劳性能对其工程实际应用具有重要意义。本文从焊接结构的疲劳理论出发,研究了名义应力法、热点应力法和等效结构应力法三种不同层次的疲劳评定方法,提出了等效结构应力法的应用策略,系统分析了梯形波纹腹板焊接梁结构的疲劳性能。主要研究工作如下:(1)开展了等效结构应力法的理论研究,给出了单元节点力的局部坐标变换方式,实现了单元线载荷矩阵的数值求解方法;分析了焊接接头局部基于SHELL单元的有限元模型构造方式,得到了 T型焊接接头进行等效结构应力法疲劳评定的建模方法;针对纵向受载的非承载型焊接结构,提出了一种纵向结构应力的构造方法。(2)分析了大量梯形波纹腹板焊接梁的疲劳试验结果,给出了弯曲作用下该结构疲劳破坏的危险位置和疲劳行为;分别采用名义应力法、热点应力法和等效结构应力法进行疲劳评定研究,结果表明:等效结构应力可比较准的预测裂纹萌生位置和估算疲劳寿命,建议采用等效结构应力作为梯形波纹腹板焊接梁的寿命评价控制参量。(3)以等效结构应力作为寿命控制参量,分析了三点弯曲和四点弯曲作用下梯形波纹腹板焊接梁的疲劳寿命,采用归一化的思想消除跨距的影响,研究了腹板波纹数量对结构疲劳性能的影响规律。提出:随波纹数量的增加,结构的疲劳强度逐渐增加;在三点弯曲循环载荷作用下,推荐腹板波纹数量取值为2n+1;在四点弯曲循环载荷作用下,推荐腹板波纹数量取值为2n+1或2n+0.5,且加载位置之间的波纹数量为整数。本文开展梯形波纹腹板焊接梁的疲劳性能研究,对梯形波纹腹板焊接梁的设计、生产与结构装配具有指导作用,对扩展其应用领域具有重要意义。
[Abstract]:Trapezoidal corrugated web welded beam is a new type of beam structure, which has been developed rapidly in recent years because of its superior mechanical properties.Trapezoidal corrugated web welded beams are mostly manufactured by welding, and fatigue property is of great significance to its practical application.Based on fatigue theory of welded structures, three different fatigue assessment methods, nominal stress method, hot spot stress method and equivalent structural stress method, are studied in this paper. The application strategy of equivalent structural stress method is put forward.The fatigue behavior of trapezoidal corrugated web welded beam structure is analyzed systematically.The main research work is as follows: (1) the theoretical study of equivalent structural stress method is carried out, and the method of local coordinate transformation of element node force is given, and the numerical solution of element line load matrix is realized.The finite element model construction method based on SHELL element is analyzed, and the fatigue evaluation method of T-type welded joint by equivalent structural stress method is obtained.In this paper, a structural method of longitudinal structural stress is put forward. The fatigue test results of a large number of trapezoidal corrugated web welded beams are analyzed, and the dangerous position and fatigue behavior of fatigue failure of the structure under bending are given.The hot spot stress method and the equivalent structure stress method are used to evaluate fatigue. The results show that the equivalent structural stress can predict the crack initiation position and estimate the fatigue life.It is suggested that the equivalent structural stress be used as the life evaluation control parameter of trapezoidal corrugated web welded beam. The fatigue life of trapezoidal corrugated web welded beam under the action of three-point bending and four-point bending is analyzed with equivalent structural stress as the life control parameter.The influence of the number of web ripples on the fatigue properties of structures was studied by using the normalized idea to eliminate the influence of span.It is proposed that the fatigue strength of the structure increases gradually with the increase of the number of ripples, that the number of web ripples is recommended as 2n 1 under the action of three-point bending cyclic load, and that under the action of four-point bending cyclic load,The recommended number of web ripples is 2n 1 or 2n 0.5, and the number of ripples between loading positions is integer.In this paper, the fatigue performance of trapezoidal corrugated web welded beams is studied, which is of great significance to the design, production and structural assembly of trapezoidal corrugated web welded beams.
【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG405

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