Welding Quality Assessment Using Waveform Signal Analysis of Vibration

摘要

The present study aims to investigate the quality of welding coupons in terms of mechanical strength by using the waveform signal analysis of time domain. The custom designed mechanical vibrator system combined with two sensor array was served to perform the tests and visualizing their results. The obtained vibration waveform from the mechanical vibration test has been compared with tensile test results. From the vibration waveform, peak to peak value is chosen to represent the waveform size, while for the tensile test result, maximum force is used to represent the strength of welding structure. The vibration waveform value then is compared with maximum force to find the relationship. From the analysis, a correlation between vibration signal and tensile strength was developed. This result agreed well with the early hypothesis of that a higher vibration waveform signal indicates a poor weld quality while the lower vibration waveform signal represents a sound quality. However, a statistical analysis reveals that there is no strong correlation between the vibration signal and mechanical strength. Despite, the acquired waveform signal was not giving an obvious indication of the hidden defects as well as its location due to the high noise level. Contradiction in results may arise due to the unbalanced data treatment and insufficient number of specimens. This study of the signal analysis method as a pre-assessment technique to quantify a weld quality, is important in the attempt to create a system monitoring for welding structure with using non-destructive test with new approach.