Q345R疲劳裂纹扩展过程的声发射研究

为了建立疲劳过程与声发射参数之间的关系,对压力容器常用钢材的典型代表——Q345R的疲劳裂纹扩展过程的声发射信号进行详细研究.结果表明:Q345R疲劳裂纹扩展的声发射过程分为三个明显的阶段,累积计数值和累积能量值可以很好地表征整个疲劳裂纹扩展过程;声发射参数在第2阶段到第3阶段的转折点比线弹性断裂力学定义下的要提前,表明声发射技术对疲劳进入失稳扩展阶段更加敏感;建立了Q345R声发射计数率和能量率与疲劳裂纹扩展速率的关系,它可以为Q345R剩余寿命的预测提供依据.

Acoustic emission study of fatigue crack propagation in Q345R

The acoustic emission signals of fatigue crack propagation in Q345R,which is the typical representative of common steel for pressure vessels,were investigated in detail to construct a relationship between fatigue and acoustic emission. The results show that there are three distinct stages of acoustic emission during fatigue crack propagation in Q345R. Cumulative count and cumulative energy can characterize the whole fatigue crack propagation well. The transition from the 2nd stage to the 3rd stage of acoustic emission advances that of linear elastic fracture mechanics,indicating that acoustic emission is more sensitive to the unstable fracture stage of fatigue crack propagation. The relations of count rate and energy rate to fatigue crack propagation rate of Q345R are established respectively for predicting the remaining life of Q345R.