采用恒载荷和慢应变速率动态拉伸实验方法，测定了X80管道钢在不同充氢条件下的氢致开裂门槛应力和断裂应力。
The threshold stress and fracture stress of hydrogen-induced cracking of X80 pipeline steel are studied by constant load test and slow stain rate test.
试验结果表明：2618铝合金表现出较高的蠕变应力指数，在引入门槛应力后，该合金的蠕变行为可得到满意解释；
It was found that 2618 aluminum alloy exhibits a higher creep stress exponent. The creep behaviors of the alloy can be described by using threshold stress.
试验结果表明：不论应力应变曲线上的直线部分是否明显，都可以用检测横波速度最大值的办法确定岩石的应力门槛值；
Whatever the straight line part of the stress-strain curve may be, it is always possible to find out the rock stress threshold by the peak value of the S-wave velocity.
预应变可以延长疲劳裂纹形成寿命，提高疲劳裂纹形成的抗力系数和裂纹形成的当量应力门槛值；
The pre-straining prolonged the fatigue crack initiation life, and increased resistance coefficient and equivalent stress threshold of the fatigue crack initiation.
本文给出二维疲劳裂纹扩展门槛值分布函数，建立二维应力—门槛值干涉模型。
A distribution function of two dimensional threshold is given for fatigue crack propagation.
随着应力比的增加，门槛值下降。
With the increase of the stress ratio r, the threshold decreased.
本文给出二维疲劳裂纹扩展门槛值分布函数，建立二维应力—门槛值干涉模型。
A distribution function of two dimensional threshold is given for fatigue crack propagation. A two dimensional stress threshold interference model is set up.
本文给出二维疲劳裂纹扩展门槛值分布函数，建立二维应力—门槛值干涉模型。
A distribution function of two dimensional threshold is given for fatigue crack propagation. A two dimensional stress threshold interference model is set up.
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