Strength measuring device of the degree of degradation evaluation method and fiber reinforced plastic fiber-reinforced plastic

摘要

PROBLEM TO BE SOLVED: To evaluate the degree of deterioration in fiber-reinforced plastic easily and precisely.;SOLUTION: An easily folded conductor such as the lead of an automatic pencil is pressed and folded. Plate waves are excited in the fiber-reinforced plastic that is a specimen. At the same time, an electric change in an electric circuit where a switch is turned off by the pressing and folding of the easily folded conductor is detected to specify an excitation time point (T₁) of the plate waves. The excited plate waves are received by a receiver. Time (T) required from the plate wave excitation time point (T₁) to a plate wave reception time point (T₂) when vibration is first received by the receiver is obtained. Distance (L) from the excitation source for the plate waves to the receiver is divided by the time (T) to calculate the group velocity of a plate wave S₀ mode in the specimen. The group velocity in the plate wave S₀ mode in the specimen is compared with the correlation relationship between the group velocity in the plate wave S₀ mode that is obtained in advance and the strength in the fiber-reinforced plastic, thus evaluating the degree of deterioration of the specimen from the strength of the specimen.;COPYRIGHT: (C)2004,JPO