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Prof.Younho Cho

Experimental study of nonlinear Lamb wave mixing in chemical exposed Aluminum alloy

Younho cho

School of Mechanical Engineering, Pusan National University, Pusan, South Korea

Nonlinear ultrasonic techniques have great potential to monitor material characterizing, closed crack, fatigue damage. Previous nonlinearity ultrasonic techniques have uncertainty due to system nonlinearity, which is caused by experimental setup, such as transducer contact condition, couplants, etc. In order to reduce the errors, we use collinear wave mixing technique. Mixed Lamb wave that made from difference of longitudinal wave and transverse wave is less sensitive to system nonlinearity due to offsetting. In this paper, we have comparison study that carried out Lame wave mixing technique and Lamb wave technique about early stage corrosion defects on Al5052 plate(T=1mm). The experimental results show that Lamb wave mixing is more sensitive to material degradation than higher harmonic nonlinear ultrasonic technique.