基于应力波的钢轨焊缝损伤检测方法研究

Nondestructive evaluation of rail weld damage based on stress wave factor

为实现对钢轨焊缝处损伤的检测,对应力波在钢轨中的传播特性进行研究。通过频散曲线得知在5 000 Hz内钢轨纵向模态导波为非频散波。使用ABAQUS有限元软件建立仿真模型,模拟轨头、轨腰、轨底处损伤,在纵向激励下对比正常工况及损伤工况应力波的传播规律。结果显示,损伤前后0.15 m内测点处峰值较正常工况明显减小,应力波在损伤前后会发生反射和衍射现象。据此,建立了一种钢轨焊缝损伤指标,沿钢轨横截面布设测点,能够检测钢轨焊缝处损伤及损伤程度。

In order to detect damage in rail welds,this paper studies the propagation characteristics of stress waves in rails.Through the dispersion curve,it is known that the longitudinal mode guided wave of the rail is a non-dispersion wave within5 000 Hz.In this paper,the ABAQUS software is used to establish the finite element model to simulate the defects at the rail head,rail waist and rail bottom.A longitudinal excitation is applied to stimulate the stress wave.Its propagation characteristics are obtained with rails in normal and defect condition.The comparison results show that a reflection and diffraction exits before and after the damage,and cause a significant change in the peak value within 0.15 m of the defect.An index is proposed to assess damage.The sensors are laid along the cross section of the rail to detect the rail weld damage.