Testing method using guided wave

A testing method using a guided wave, of generating a guided wave to propagate through a subject in a shape of a rod or a tube as a testing target in a longitudinal direction of the subject, detecting a reflected wave of the guided wave and estimating a defect cross-sectional area and a defect width of a defect part existing in the subject on a basis of the reflected wave,

• wherein the defect cross-sectional area refers to a cross-sectional area of the defect part taken along a plane orthogonal to an axial direction of the subject, and the defect width refers to a width of the defect part in the axial direction of the subject,
• wherein the method comprises the steps of:
• (A) obtaining first data for defect amount estimation for the guided wave of a first frequency beforehand, the first data for defect amount estimation indicating a relationship among amplitude of the reflected wave, a defect cross-sectional area and a defect width,
• (B) obtaining second data for defect amount estimation for the guided wave of a second frequency beforehand, the second data for defect amount estimation indicating a relationship among amplitude of the reflected wave, a defect cross-sectional area and a defect width,
• (C) generating a guided wave of the first frequency so as to propagate through the subject, and detecting amplitude of a reflected wave of the guided wave as first amplitude,
• (D) generating a guided wave of the second frequency so as to propagate through the subject, and detecting amplitude of a reflected wave of the guided wave as second amplitude, and
• (E) on a basis of the first and second data for defect amount estimation and the first and second amplitude, estimating a defect cross-sectional area and a defect width of the defect part.