The Effect Of High Frequency Wave In Vibro Acoustic Method For Crack Detection

Anuar, Nurul Husnina (2017) The Effect Of High Frequency Wave In Vibro Acoustic Method For Crack Detection. Project Report. UTeM, Melaka, Malaysia. (Submitted)

Text (24 Pages) The Effect Of High Frequency Wave In Vibro Acoustic Method For Crack Detection.pdf - Submitted Version Download (301kB)

Abstract

The most common structural defect is the existence of fatigue crack. Fatigue cracks can present in the structures due to various reasons. The presence of cracks is hazardous as it can affect the mechanical behaviour of the entire structure to a considerable extent, thus a non-linear vibro-acoustic approach suitable for detecting the presence of fatigue crack as they are very sensitive even to a small damage severities or cracks and highly reliable method. This study is carried out to study about crack detection on a structure by using a non-linear vibro-acoustic technique. Vibro-acoustic method is a method based on propagation of high frequency acoustic waves in solid structures with low-frequency excitation. The interaction occur between the acoustic waves with material changes will cause wave distortion effects. The main objective of this study to find effects of high frequencies against the non-linear effects sensitivity using variation of high frequency wave in vibro-acoustic method to detect the fatigue crack. The test specimen that will be used in this study is a 150 mm x 400 mm x 2 mm aluminium plate (AL-2024). The plate will undergo some modal analysis to determine the dynamic response of a material and followed by the vibro-acoustic test. In addition, this study also will provide analysis on the relation of high frequency effect and the amplitude modulation intensity (R-value). The findings show that crack exhibited in a power spectra signal of the acoustic response by a pattern of sidebands around the ultrasonic signal and explains that the high frequencies excitation does not give significant change on the modulation intensity but proper selection of the high frequency excitation value and also its location is important to obtain a good result.

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