以成组疲劳试验确定疲劳极限的损伤力学方法

THE DAMAGE MECHANICS APPROACH IDENTIFYING FATIGUE LIMIT BY FATIGUE

  • 摘要: 为降低用来确定疲劳极限的升降法试验的工作量,以热力学为基础,引入损伤驱动力,构建损伤演化方程. 积分此方程得到疲劳寿命与应力或应变的理论关系. 对光滑试件,根据成组法疲劳试验结果利用最小二乘法拟合包括疲劳极限在内的材质参数. 利用损伤力学方法求得高应力区的疲劳寿命曲线,由此递推得到低应力区寿命值和疲劳极限. 所得理论疲劳极限值与升降法疲劳试验结果十分吻合. 节约了疲劳试验的机时、费用与人力.

     

    Abstract: Based on irreversible thermodynamics, the damage evolutionequation is constructed by introducing the damage driving force, in order toreduce the work of the up-down method in identifying the fatiguelimit. The theoretical relationship between fatigue life and stress orstrain can be obtained by integrating the damage evolutionequation. For smooth members of structure, according to the results offatigue experiment with group method, the material parameters of damageevolution equation, including the fatigue limit, are determined by the leastsquares technique. The curves of fatigue life in high stress area areobtained by the damage mechanics. And then, the fatigue life and fatiguelimit in low stress area are deduced. The results of theoreticalfatigue limit agree well with the fatigue experimental results ofup-down method. By using this method, a lot of time, cost and manpowerin fatigue experiment can be saved.

     

/

返回文章
返回