基于Strohmeyer模型的金属材料P-S-N曲线表征方法研究

Characterization Method for P-S-N Curve of Metal Material Based on Strohmeyer Model

基于Strohmeyer模型提出一种考虑置信度的金属材料P-S-N曲线通用表征方法,利用非线性最小二乘法(NLS)拟合得到高精度P-S-N曲线。考虑金属材料寿命及测试应力分散性,提出单一寿命模型和改进三参数分散度模型,结合对数寿命标准差与应力的相关性分析数据离散度,分别利用2A12铝合金和BSM590钢材料验证了可行性。研究结果表明:利用所提出的表征方法预测疲劳极限,误差小于10%,分散度模型调整系数提高超过0.4,拟合精度显著提高,对结构件的精细化可靠性设计提供了技术支撑。

Based on Strohmeyer model,a general characterization method of metal material P-S-N curve considering confidence was proposed,and high precision P-S-N curve was obtained by nonlinear least squares(NLS)fitting.Considering the lifespan of metal material and the dispersion of testing stress,a single lifespan model and an improved three-parameter dispersion model were proposed.Combined with the correlation analysis of logarithmic lifespan standard deviation and stress,the data dispersion was analyzed,and the feasibility was verified with 2A12 aluminum alloy and BSM590 steel metal materials.The research results indicate that the proposed characterization method predicts fatigue lifetime with an error of less than 10%,the adjustment coefficient of dispersion model increases by beyond 0.4,and the fitting accuracy significantly improves,providing technical support for the refined reliability design of structural components.