热点应力有限元分析的主要影响因素

用热点应力方法评定焊接结构的疲劳强度获得了越来越广泛的应用。在热点应力方法中，有限元分析是至关重要的。热点应力的外推方法、有限元网格尺寸大小是影响计算精度的主要因素。文中对三点弯焊接接头进行了有限元计算，比较分析了由不同外推方法和有限元网格划分得到的热点应力，说明了网格尺寸对热点应力有较大的影响，在网格划分时要考虑单元类型的影响。外推方法对热点应力的影响不是很大，一般情况下可用两点线性外推。

Key influence factors in hot spot stress FEM analysis

Hot spot stress method used for evaluating fatigue strength of welded structure has obtained more and more application,the FEM is vital in this method.The key factors influencing calculation precision are extrapolation methods and mesh size.The FEM analysis has been done in three points bending welded joint,the hot spot stresses of different extrapolation methods and mesh size are compared.The results show that mesh size has greatly effect on hot spot stress,and element type should be considered in meshing,however,extrapolation methods have little effect on calculation precision relatively,two points linear extrapolation can be applied to welded joints in general.