報告書番号

Q07012

タイトル（和文）

光ファイバAEによる損傷監視手法の開発-第2報：センサ耐久性向上と実機模擬環境下でのAE計測

タイトル（英文）

Development of Damage Monitoring Technique using Optical Fiber AE Sensors -Part2: Improvement of Heat-resistant Sensor and AE Measurement during Fatigue or Internal Pressure Creep Test of Actual Components-

概要 （図表や脚注は「報告書全文」に掲載しております）

弱いセンサ付根部分に局所的に金属コーティングを施してファイバを補強することで，耐熱センサを外力の作用に強い構造に改良し，室温-650℃の温度サイクル作用時も断線せず使用可能であることを確認した．常温用センサを用いて，低合金鋼溶接継手のCT疲労き裂進展試験中のAE計測を行い，き裂の進展・停留過程において長さ0.04mm程度のき裂進展のAEを検出することに成功した．一方耐熱センサを高クロム鋼溶接管の内圧クリープ試験中のAE計測に適用した結果，巨視き裂貫通や蒸気漏洩によるAEは検出できたが，クリープ損傷進行過程でのAEは検出できなかった．き裂がどの程度進めばAEとして検出可能か評価するために，AE発生を模擬した有限要素弾性波伝播シミュレーションを行った結果，耐熱センサを用いた場合，実規模配管における半径2mm以上の割れを検出可能と推定された．この結果から，巻数を多くして耐熱センサの感度を向上させることで，より微小な高温でのき裂進展のAE検出も可能となることが示唆された．

概要 （英文）

CRIEPI has developed the fiber-optic sensor that can be applied up to 600 degree C and measurement system. In previous report, we have developed practical sensor installation technique of the sensor for a high-temperature piping and have demonstrated that the accuracy of source location on piping can be increased using wavelet-based technique. However, reliability of conventional heat-resistant sensor was poor due to brittleness of fiber and structural design. In this report, improvement of heat-resistant sensor was successfully carried out and the sensor could be applied up to 650 degree C. AE monitoring during CT fatigue crack propagation test of low alloy steel welded joint using room temperature type sensor was carried out and AE signals due to crack propagation length of approximately 0.04mm were successfully detected. AE monitoring during internal pressure creep test of high chromium steel welded joint using the heat-resistant sensor was carried out and AE signals at penetration of macrocrack or due to steam leakage were detected. However, AE signals due to creep damage were not detected. Minimum detectable size of microcrack using the fiber-optic sensors was evaluated based on FEM simulation of elastic wave propagation. It was estimated that microcracks radius of above 2mm could be detected using the heat-resistant sensor on an actual steam piping.

報告者

キーワード