NONDESTRUCTIVE INSPECTION METHOD

• Main Authors: UCHIDA TORU, SHIRAISHI HIROZO, NAKANISHI YOSHIKAZU
• Format: Patent
• Language: English; Japanese
• Published: 28.12.2023
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

To provide a nondestructive inspection method that can accurately estimate presence or absence of damage to a reinforcing bar provided in a concrete structure.SOLUTION: A nondestructive inspection method includes: measuring magnetic flux density in a first direction of an object to be inspected P at a plurality of measurement positions arranged side by side along a second direction parallel to a surface CF of a concrete structure C and orthogonal to the first direction; forming, for each of the measurement positions, a first direction fluctuation curve indicating fluctuations along the first direction of the magnetic flux density in the first direction measured at the plurality of measurement positions; forming a first direction differential curve obtained by performing first-order differentiation of the first direction fluctuation curve at each measurement position; calculating, for the first direction differential curve at each measurement position, a difference ΔdBx between a maximum value and a minimum value across a position where the first direction differential curve becomes 0 and/or the difference ΔdXx between a position of the maximum value and a position of the minimum value across the position where the first direction differential curve becomes 0; and determining presence or absence of fracture of the object to be inspected P on the basis of the difference ΔdBx and/or the difference ΔdXx.SELECTED DRAWING: Figure 1 【課題】コンクリート構造物内に設けられた鉄筋等の損傷の有無を精度よく推定することができる非破壊検査方法を提供する。【解決手段】コンクリート構造物Ｃの表面ＣＦと平行かつ検査対象Ｐの第一方向と直交する第二方向に沿って並んだ複数の測定位置で第一方向の磁束密度を測定し、複数の測定位置において測定された第一方向の磁束密度の第一方向に沿った変動を示す第一方向変動曲線を各測定位置についてそれぞれ形成し、各測定位置の第一方向変動曲線を一階微分した第一方向微分曲線をそれぞれ形成し、各測定位置の第一方向微分曲線について、第一方向微分曲線が０となる位置を挟む極大値と極小値の差ΔｄＢｘ、および／または、第一方向微分曲線が０となる位置を挟む極大値の位置と極小値の位置の差ΔｄＸｘをそれぞれ算出し、差ΔｄＢｘおよび／または差ΔｄＸｘに基づいて検査対象Ｐの破断の有無を判断する。【選択図】図１