The relationship between damage variable D(K_1 ) and number of fatigue cycles (N) can be used to detect fatigue damage and to divine fatigue life tbr metal materials.

• 利用损伤变量D(K_1)和循环次数N的关系曲线,可以对材料进行疲劳损伤检测并对其疲劳寿命进行预测。