Magnetorestrictive transducer for generating and measuring elastic waves, and apparatus for structural diagnosis using the same

Apparatus for structural diagnosis using magnetostrictive transducers comprising:

• two magnetostrictive transducers, each of the two magnetostrictive transducers comprising a patch made of ferromagnetic material and a magnetic field generator, placed above the patch, for generating magnetic field applied to the patch;
• a power source for supplying electric currents to the magnetostrictive transducer;
• and
• a measuring unit for measuring voltage output of the magnetostrictive transducer,
• wherein the magnetic field generator comprises:
• a main body made of non-magnetic material;
• two magnets for generating bias magnetic field applied to the patch, the magnets being located in upper part of the main body, the magnets being apart from each other;
• and a coil for winding round the magnets,
• wherein, as an alternating current is supplied to the coil of a first transducer of the two transducers, the patch generates Lamb waves in direction of the magnetic field and shear horizontal (SH) waves in direction forming predetermined angle with the direction of the magnetic field,
• wherein, as the patch of the second transducer goes through mechanical deformation due to the Lamb waves or the SH waves from the first transducer, the magnetic field of the second transducer varies and amount of the voltage across the coil of the second transducer varies due to the variation of the magnetic field, and
• wherein defects of testing plate existing in traveling route of the Lamb waves or the SH waves from the first transducer are detected by the measuring unit's measuring the voltage variation across the coil of the second transducer.