新旧钢规下重级钢吊车梁疲劳验算的对比分析  

Comparison and analysis on fatigue calculation of heavy steel crane beams under old and new design code for steel structures

作　　者：储鹏宇 CHU Pengyu(Shanghai Nenghui Technology Co.,Ltd.,Shanghai 200335,China)

机构地区：[1]上海能辉科技股份有限公司,上海200335

出　　处：《工程建设》2022年第1期29-34,共6页Engineering Construction

摘　　要：疲劳验算是重级钢吊车梁设计的重要内容,新版《钢结构设计标准》引入疲劳截止限的快速判别法,明确区分正应力幅和剪应力幅,并对验算部位的类别进行重新划分。为了更好地把握重级钢吊车梁的疲劳验算要点,让新钢规可以更有效地指导吊车梁设计,本文对新、旧钢规的疲劳验算进行归纳总结,并结合具体工程实例进行分析计算。结果表明:当吊车梁承受高应力幅时,利用疲劳截止限快速判别出正应力幅一般较容易满足,而剪应力幅较难满足,需按容许应力幅法进一步判断。此外,通过理论公式和Sap2000有限元软件相结合的方法,对3种变截面吊车梁的疲劳验算结果进行对比分析,得出疲劳应力幅大小关系:圆弧突变式>渐变式>直角突变式。其中对于直角突变式吊车梁,其理论计算的疲劳应力集中系数偏大于有限元分析值,验证了新钢规中关于直角突变吊车梁对抗疲劳更为有利的结论。Fatigue calculation is an important element in the design of heavy steel crane beams, and the new version of Steel Design Standard introduces the rapid discrimination method of fatigue cut-off limit, clearly distinguishes the positive stress amplitude and shear stress amplitude, and redivides the categories of calculation parts.In order to better grasp the fatigue calculation points of heavy steel crane beams, so that the new design code for steel structures can guide the design of crane beams more effectively, the fatigue calculation of new and old steel regulations is summarized, while the specific engineering examples are combined to deal with analysis and calculation.The results show that, when the crane beam is subjected to high stress amplitude, it is generally easier to satisfy the positive stress amplitude by using the fatigue cut-off limit to quickly discriminate the positive stress amplitude, while the shear stress amplitude is more difficult to satisfy and needs to be further judged according to the allowable stress amplitude method.In addition, through the combination of theoretical formula and Sap2000 finite element software, the fatigue calculation results of three kinds of variable section crane beams are compared and analyzed, and the relationship between the fatigue stress magnitude and size is obtained: arc mutation type>gradual change type>right angle mutation type.Among them, for the right angle mutation crane beams, the fatigue stress concentration coefficient of the theoretical calculation is larger than that of the finite element analysis value, which verifies the conclusion that the right angle mutation crane beams are more favorable to fatigue resistance in the new design code for steel structures.

关 键 词：疲劳验算 重级钢吊车梁 新旧钢规 变截面吊车梁 疲劳截止限 

分 类 号：TU391[建筑科学—结构工程]