| 摘要 |
PURPOSE:To improve the detection capacity by providing transmitting and receiving transducers so that they face both of front and rear faces of a sample plate body and generating Lorentz forces on both of front and rear faces to give oscillation and utilizing oscillations of both of front and rear faces for detection of properties. CONSTITUTION:When plate waves 18 generated by the first and the second transmitting transducers 19a and 19b reach a part under the influence of the reception-side static magnetic field, eddy currents are generated in outer parts of front and rear faces by the interaction. An alternating magnetic field due to these eddy currents intersects with oscillation detecting coils 26a and 26b of the first and the second receiving transducers 24a and 24b to induce currents. These induced currents are amplified by amplifiers 27a and 27b and are added in an adder 28 and are sent to a discriminator 29. The discriminator 29 grasps the propagation time and the attenuation quantity of plate waves 18 on a basis of the added signal to discriminate properties of presence/absence of defects, the material, etc. of a sample plate body 16. Since oscillations of both of front and rear faces are used for detection, the detection capacity is improved. |
