J0402-2-6 Zero group velocityラム波を用いた不飽和ポリエステルの劣化評価([J0402-2]超音波計測・解析法の新展開(2))

概要

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A lot of FRP storage tanks are used in chemical plants due to its superior anti-corrosion performance. However, it is difficult to estimate degree of degradation of FRP by an eye inspection. This study aims to evaluate the degree of degradation of an unsaturated polyester resin plate which is used as a matrix of FRP by zero-group-velocity (ZGV) lamb waves. The samples were degraded by immersing the resin into hot water of 90 ℃. ZGV Lamb wave was generated and detected by a Q-switched YAG laser with diameter of 4 mm and a heterodyne type laser interferometer with probe diameter of 0.1 mm. Measured Frequency of ZGV lamb wave for degraded samples decreased with immersion period. This Drop of the measured frequency means that elastic properties of the degraded samples reduced. Depth of discolored area of cross-section of the samples observed by optical micro-scope increased with immersion period and corresponded with gradated depth of the sample. However, no cracks were not observed in the discolored area. It is found that ZGV lamb wave can detect early stage of degradation of the resin.
2010-09-04