复合材料I形梁分层的光纤超声探测技术数值研究

针对纤维增强塑料多界面、高阻尼以及体波模式多样性对超声无损检测的影响, 介绍了一种利用光纤超声探测技术结合小波信号分析检测I 形纤维增强塑料梁中分层的方法。该方法利用超声发射器在梁中产生超声应力波, 用表面粘贴的光纤干涉仪来探测梁中应力波的传播情况, 然后利用小波的多分辨率特性对此信号进行时频分析, 结合梁中超声波的传播特性即可确定分层的位置。理论分析和模拟结果都表明了此方法探测复合材料梁腹板/翼缘连接处分层的可行性。 

Numerical study on delamination detection in I-section GFRP beam with optical fiber-based ultrasonic technique

In order to overcome the effect s of FRP multi-interface, high damping characteristics and diversity of the body wave mode on the ultrasonic nondestructive test, a novel technique for detecting delamination is proposed. A PZT transmitter was employed to create the stress waves in the beam, and an optical fiber interferometric sensor was attached to the surface of the beam to detect the stress wave propagation in the beam. By analyzing the propagation characteristics of ultrasound and the wavelet time-frequency spectrum of the signal, the delamination location can be identified. Based on the theoretical analysis and simulation results, the feasibility of delamination detection with the proposed technique is demonst rated.