焊接结构主S-N曲线拟合方法及软件开发

Master S-N curve fitting method of welded structure and software development

关键词:  主S-N曲线法  结构应力  最小二乘法  软件开发

Key words:  master S-N curve  structural stress  least squares method  software development

摘要:

主S-N曲线法是当前焊接结构疲劳计算的新方法，在焊接结构疲劳分析中被广泛采用. 该方法以等效结构应力为核心参量，实现了以一条S-N曲线计算不同载荷模式和焊接形式结构的疲劳寿命. 依据主S-N曲线法，利用不同材料和焊接形式的疲劳试验建立了焊接结构疲劳试验数据库. 考虑厚度、弯曲比及多轴应力等修正参量的影响，采用最小二乘法原理，研究了不同主S-N曲线方程的拟合方法及其标准差. 在此基础上，开发了主S-N曲线拟合方法的专用软件. 基于VC++编程环境实现了名义应力、结构应力、等效结构应力、剪切结构应力、多轴结构应力及初始裂纹修正等主要计算功能. 基于该软件，完成了试验数据的多参量的对比分析，为研究焊接结构疲劳寿命评估及影响因素分析提供了技术基础.

Abstract:

The main S-N curve method is a new method to calculate the fatigue life of welded structures. It is widely used in the fatigue analysis of welded structures. The equivalent structural stress is taken as the key parameter to calculate the fatigue life of structures with different loading modes and welding forms by single one S-N curve. Based on the principle of the master S-N curve method, a database of welded structure was created through different materials and welding forms of fatigue test. The effects of correction parameters such as thickness, bending ratio and multi-axial stress were taken into concern to study the different master S-N curve equations fitting method and its standard deviation base on the principle of least squares method. The special software for the master S-N curve fitting method was developed. Based on VC++ programming environment the main calculation functions of nominal stress, structural stress, equivalent structural stress, shear structural stress, multi-axial structural stress and initial crack correction were compiled. The multi parameter comparative analysis of the test data was completed in this software. It provides a technical basis for the study of fatigue life assessment and influencing factors analysis of welded structures.