應用可移動式感應陣列及概率損傷成像法於非平纖維複合材料薄板之隱藏損傷監測

Abstract

本文研究以概率損傷成像法為複合材料損傷定位算法之基礎，由壓電陶瓷所組成的大型矩形感應陣列實現全域的損傷定位監測，其結果透過實驗驗證了概率損傷成像法於平板/曲面之玻纖複合材料檢測模擬分層的損傷定位能力。另一方面永久安裝的壓電陶瓷陣列普遍需要健康無損的基線訊號，然而基線訊號又易受到環境因素的影響導致基線訊號不一致。為此本文提出了一種無基線檢測方法，採用可移動式探頭夾具用於檢測平面、曲面結構之局部區域損傷量測，該方法建立一套移動式感應陣列，結合乾耦合的接觸模式以及一發一收的傳輸模式下實現移動式量測。此時根據時間互易性原理，沿感應訊號的非線性散射將影響彈性響應信號的幅度和相位，即正向傳播訊號和反向傳播訊號之波形可能不全然相同。由本研究中將結合概率損傷成像法以及時間互易性原理下實現無須基線的概率損傷成像法，由實驗結果中成功定位來自表面以及隱藏於結構表面之損傷缺陷處於平面以及曲面結構。

This study based on a damage detection algorithm based on the probabilistic inspection of damage tomography. It consists of PZTs for large sensor array network arranged in rectangular. Validate the credibility of imaging method on GFRP curved and flat plate with artificially delamination-like defect. However, lamb wave based defect detection approach which conventional surface-bonded PZT usually rely on reference signals which are influenced by environmental conditions. To solve this problem, a mobile line scanning detection at detection region based on a baseline-free detection approach using mobile piezoelectric transducers is proposed herein. As stated above, mobile transducer array mechanism combined with the principle of dry-coupling and pitch-catch method. The nonlinear scatter along the wave path will affect both amplitude and phase of elastic response signals. Therefore, the waveform of the elastic response signals may not be the same when wave going from forward propagation signal and from back propagation signal on account of time reciprocity. Two experiment were conducted to validate the proposed method on GFRP curved plate and flat plate with artificially crack-like damage. The results show that the proposed baseline-free approach can locate the hidden crack ,hole ,circular defect. The proposed baseline-free method provides a novel damage detection approach when considering the time-reciprocity scatting characteristic of lamb waves.