一种疲劳损伤参数确定新方法

A novel method for determining fatigue damage parameters

金属材料的疲劳断裂是工程结构中常见的失效模式。损伤力学将裂纹萌生视为渐进损伤过程,通过损伤演化方程描述并进行寿命预估。但损伤演化方程中的参数需要根据标准实验数据拟合得到,此过程通常需要多参数联合拟合,运算复杂,计算量大,物理意义不明确。为了避免上述问题,基于损伤力学的理论基础,提出了一种新的损伤演化方程参数确定方法,即根据损伤演化方程的性质,结合S-N曲线的特质,通过数学方法提出一种单一参数确定损伤演化方程的单参数方法。本文方法规避了多参数同时拟合的缺点,提高了计算速度计算精度,为工程分析提供了新的选择。通过具体算例验证了本文方法的使用效果。

Fatigue fracture of metal materials is a common failure mode in engineering structures. Damage mechanics regards crack initiation as a progressive damage process,describing and conducting life estimates through the damage evolution equation. However,the parameters in the damage evolution equation need to be fitted according to the standard experimental data. This process usually requires multi-parameter fitting,which involves complicated operation,large computational amount and vague physical meaning. To avoid these problems,based on the theoretical basis of damage mechanics,a new method to determine the parameters of damage evolution equation was proposed. According to the properties of damage evolution equation and the characteristics of S-N curves,a single parameter method,which employs single parameter to determine the damage evolution equation,was proposed using mathematical method. The proposed method avoids the disadvantage of multi-parameter fitting at the same time and improves the calculation accuracy and speed,which provides an alternative for engineering analysis. Finally,a concrete example is given to demonstrate the effect of the proposed method.