Simulation Of Partial Thickness Defect In Pipe Based On The Ultrasonic Guided Wave

The wear,corrosion,accidental damage will do harm to the normal usage of the pipeline after long-term operation.In the working conditions,the small corrosion defects can easily develop into corrosion failure.Meanwhile,small crack in the shallow layer is likely to lead to through thickness crack.Therefore,research on detection of defect effectively is necessary.By using ANSYS,the simulation research of detecting thinning defects in hollow pipe and water-filled pipe.Defect detection of pipes were numerically simulated for the circumferential and longitudinal partial thickness defects using L(0,2)and T(0,1)modes,the relationship between the feature size and reflection coefficient of cracks were obtained,Simulated L(0,2)models of detection signals for pipes with internal or external hole defect,the difference between two reflection coefficient is extremely small.Therefore,Simulated for pipes with pit defect in same cross-sectional area and different shape,guided waves are more sensitive to narrow and deep defects.by using the time reversal,the signal multiplication and circumferential positions of small defect is been researched,and the result shows that the time reversal method could amplify the defect signal and the circumferential location and the shape of the crack could be distinguish effectively.The simulation research of detecting the circumferential and multiple circumferential defects in water-filled pipe by using L(0,2)guided waves,the relationship between the feature size and reflection coefficient of cracks were obtained,the reflection coefficient is compared with the hollow pipe in common defect,the hollow pipe was always bigger than the water-filled pipe.The circumferential positions of various types cracks by using time reversal was been researched in this paper,the simulated result shows that after reset the time reversal signal,the circumferential positions and shape discrimination for water-filled pipe with multiple cracks,could get the number of defects and the longitudinal position of small cracks in different axial position.