基于多轴疲劳理论的冶金起重机主梁母材疲劳失效机理研究

Research on fatigue failure mechanism of base metal of main beam of metallurgical crane based on multi-axis fatigue theory

冶金起重机金属结构件的主要失效形式是疲劳破坏,疲劳失效多发于疲劳性能薄弱、应力最大或应力集中处。以往的疲劳研究往往只考虑垂直和水平方向的载荷受力,理论设计疲劳强度余量较大。由于实际工况比较复杂,使用一定年限的冶金起重机母材会出现主梁开裂现象,高温环境下、垂直载荷、水平方向冲击载荷、大车轨道高差、钢丝绳吊载晃动等因素会导致拉伸-扭转多轴疲劳载荷。鉴于此,文中基于实际工况背景,以常用主梁箱体钢结构材料Q345B为研究对象,在实验室进行不同加载参量下的多轴高周疲劳试验,从而研究冶金起重机多轴高周疲劳失效的机理。

The fatigue failure of metal structural parts of metallurgical cranes is the main failure mode,which often occurs at places with poor fatigue performance,maximum stress or stress concentration.In previous researches on fatigue,only vertical and horizontal loads were considered,and the theoretical design fatigue strength margin was large.Due to the complicated working conditions,the main girder of metallurgical crane base metal will crack after being used for a certain number of years,and factors such as high temperature,vertical load,horizontal impact load,track height difference of cart,and wire rope hanging load shaking will lead to tensile-torsional multiaxial fatigue load.Therefore,in this paper,based on the actual working conditions,the multi-axial high-cycle fatigue tests with different loading parameters were carried out in the laboratory,taking the common main girder box steel structure Q345B as the research object to study the multi-axial high-cycle fatigue failure mechanism of metallurgical cranes.