Koh Boon Hao
Metric No: BK10110124
Topic: PWAS GENERATED LAMB WAVE SPEED DISPERSION CURVE PROPAGATION ON ALUMINIUM THIN PLATE
Abstract: After a long period of service, most of the engineering structures will face deterioration and damage problem in that particular structure such as civil, aerospace and marine structures. Regular structural maintenance often performs over a period of time to prevent the failure on the structure itself. Hence, structural health monitoring (SHM) technology is introduced to detect the potential hazardous damages and also to ensure the serviceability and sustainability of the structures itself. Traditional nondestructive evaluation (NDE) techniques are difficult to use in operation due to the cost, size and weight of necessary devices. A new nondestructive evaluation (NDE) method using piezoelectric wafer active sensors (PWAS) Lamb waves based for structural health monitoring has been proposed to overcome the limitations of the conventional methods as it allows the inspection of large area from one single location. However, the nature of Lamb wave makes the interpretation and analysis of the wave result very complex due to their dispersive and multimodal natures. One of the fundamental theories, Lamb wave dispersion curve analysis has been done by several researchers. However, the speed dispersion curve is hard to achieve practically. The speed dispersion curve is demonstrated through the experiments on the aluminium thin plate where flat and inclined aluminium plates were used. Signal processing was implemented on the data collected in order to get a clearer time of flight. The experimental values were then compared with the theoretical values that obtained from MATLAB. In this study, the Lamb wave velocity dispersion curve is successfully plotted, and compared with the theoretical velocity dispersion curve.