J044014 広帯域ラム波のモード変換に基づくCFRP積層板の層間剥離検知における環境温度の影響評価([J04401]知的材料・構造システム(1))

概要

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The authors have developed abuilt-in ultrasonic propagation system consisting of MFC actuators and FBG sensors, which can be integrated into CFRP laminates. This system can propagate multiple modes of broadband Lamb waves and can identify all the modes by synchronization of two MFCs and two FBGs on both surfaces of the laminate. Hence, a new delamination detection method has been established on the basis of the dispersion change caused by the mode conversions at the delamination edges. However, the frequency dispersion is also affected by the temperature change. The compensation of the temperature effect is important for practical use. Hence, in this research, we conducted experiments for CFRP quasi-isotropic laminates with an artificial delamination at various temperatures in a thermostatic chamber, in order to investigate the temperature effect on the frequency dispersion of anti-symmetric (A) mode. As a result, with an increase in the temperature, the time of flight (ToF) of Ao mode increased and that of Al mode decreased. However, ToF of Ao mode was independent of delamination length L because of the mode conversions. Hence the environmental temperature can be used to compensate the temperature effect on the change in the dispersion slope of A I mode. Therefore, we will be able to evaluate the delamination length in CFRP laminates with compensation of temperature chage.
一般社団法人日本機械学会の論文
2011-09-11