Highly sensitive defect detection using multireflecting guided wave energy trapping (MGET) method

The authors have previously been reported a novel method of an efficient transduction method for guided waves using the wave reflector just located near the sensor. The sensitivity of the method with the reflector has been 2.0-2.5 times larger than that without the reflector. This paper describes a much more efficient method for defect detection using guided waves with two reflectors. The novel method called Multireflecting Guided wave Energy Trapping (MGET) method is evolved from the above-described efficient method. When the guided waves are trapped between the two reflectors, n combinations of propagation paths having same path length are principally existed at the n times multireflections. Therefore the amplitudes of the defect signals are overlapped each other and are enhanced. Details of the principle and experimental verifications are shown. The sensitivity of the MGET method was evaluated about 10 times larger than that of the conventional guided wave method. (author)