非接触変位場応答計測に基づく不可視損傷検出の基礎的研究  [in Japanese] FUNDAMENTAL STUDY ON INVISIBLE CRACK DETECTION BASED ON NON-CONTACT DISPLACEMENT MEASUREMENTS  [in Japanese]

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Abstract

構造物の健全性を評価する上でき裂の検出は重要であり,多くの方法が提案されている.中でも可視光画像を用いた方法は簡便で有望視されており,パターン認識手法を利用したき裂検出システム等が提案されている.しかし,これらはき裂そのものに着目した方法であり,不可視の状態にあるき裂を検出することはできない.本研究では荷重変動に伴うき裂開閉挙動に着目し,き裂の発生・進展前の画像を必要とせず,不可視な状態にあるき裂を検出するシステムの開発を目的として,デジタル画像相関法により被写体表面の変位場を取得し,き裂開口に伴う見かけ上のひずみ場を算出・評価する.コンクリートおよびあらかじめ切断された鋼板にCFRPを接着した供試体に対して実証試験を行い,本システムの有効性を検証した.

The numerous methods of a crack detection have been developed for the purpose of assessing the integrity of the structure. Among them, pattern recognition techniques for digital image are to evaluate cracks morphologically based on image processing, which are effective in the case that the crack on the surface is visually apparent. However, fault detection might be unavoidable in principal of the system for the crack which is difficult to identify visually due to surface condition of the observation structures.<br>An attempt is made in this study to develop an invisible crack detection system based on non-contact displacement measurements. The maximum principal strain and the principal direction, which are calculated from the displacement vectors, are the prime parameters for crack identification. Based on the maximum principal strain and principal direction, the proposed system detects crack in each discretized elements on the digital image. The validity of the proposed SHM system is demonstrated through laboratory experiment.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM))

    Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)) 72(2), I_87-I_96, 2016

    Japan Society of Civil Engineers

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