Prediction of Crack Locations using Non Destructive Tests

Objectives: In this paper non destructive tests are used to find the location of multiple cracks in the cantilever beam. Methods/ Analysis: The impact echo test along with Ultrasonic Pulse Velocity (UPV) test is used to find the crack locations. These tests are conducted on cantilever beam having two cracks at different positions. The frequency spectrum is recorded from the impact echo test. While the ultrasonic pulse time is recorded from ultrasonic pulse velocity test. A MATLAB based code is used to find out the dominant frequency of the sound signals corresponding to each impact echo test. The ultrasonic pulse velocities are calculated from the travel time and the distance between the transducers. Findings: It was found that the frequency values are increasing when the cracks move away from the fixed end of the cantilever beam since the frequency ratio increases when the distance of the crack increases from fixed end (based on Equation 3). Ultrasonic pulse velocity also increases since the distance between the transducers of the UPV equipment decreases when the location of crack changes. Applications/Improvements: From the values of frequency and ultrasonic pulse velocity, mathematical expressions of crack location are developed. The developed expressions are tested on the cantilever beam to find the crack locations in a laboratory model.