Preliminary Study Of Rail Damage Detection And Allocation

Many major accidents happened are closely related to the rail damage,so study on the rail flaw detection technology is particularly important nowadays.This paper studied rail damage detection and allocation with nondestructive method using piezoelectric transducers(PZT)and guided Lamb wave.Active sensing system was proposed to realize the real-time monitoring of the rails.Meanwhile,reflected wave and time reversal method(TRM)were used to allocate the damage.Firstly,Lamb wave dispersion curve was plotted based on the dispersion equation numerical solution to get better understanding of the stress wave form and propagation velocity.Optimized frequency of the five-cycle Hanning-windowed tone burst wave was selected based on the distance of stress wave propagation using the active sensing system.Secondly,different PZT actuator and sensor arrangement was explored.And damage criteria were obtained by analyzing the waveform and power spectrum density estimate.Reflection wave was also used to allocate the damage by utilizing the difference signal.Its feasibility and limitation in practical application were also discussed in this study.Thirdly,the positioning relationship between the focalized signal with damage and the whole time window were obtained by the TRM.The relationship facilitated identifying the damage time information.TRM were also applied to the two sensor arrangements to allocate the damage,showingrelatively accurate results.Finally,three damage index definition methods from the aspects of similarity,difference and accuracy were put forward to judge the damage degree based on the two sensor arrangements.The fitting curve of the damage indexes can help predict the degree of damage.