In this paper, a low-power fully acoustic non-destructive testing (NDT) of glass fiber-reinforced composite plate has been presented. Input acoustic power in microwatt range was used for local defect resonance (LDR)-based delamination activation. Besides experimental results, numerical simulations were carried out via commercial ABAQUS platform. An oblique incident wave interaction with 3D composite plate was created, and the sound radiation pattern over the plate was studied with an air layer over the plate. In experiment, the sound was generated by a piezospeaker, while a MEMS microphone was used for reception over the plate. Moreover, a laser Doppler vibrometer was utilized for the LDR frequency and corresponding mode shape validation. Frequency spectrum, mode shape at LDR frequency, best wave impinging angle, efficiency, and sound directivity patterns were studied, with angles θ, ϕ = 10°, 30° being found to correspond to the best direction for sonic excitation. Moreover, fully acoustic system was found to be more efficient than partial acoustic system, i.e., that with contact excitation. The proposed method can be used for inspection of large structures taking advantage of the long-distance non-contact excitation.

本文提出了一种玻璃纤维增​​强复合板的低​​功率全声无损检测（NDT）。微瓦范围内的输入声功率用于基于局部缺陷共振（LDR）的分层激活。除实验结果外，还通过商业ABAQUS平台进行了数值模拟。创建了与 3D 复合板的斜入射波相互作用，并研究了板上方有空气层的情况下板上方的声辐射模式。在实验中，声音由压电扬声器产生，而 MEMS 麦克风则用于通过板进行接收。此外，激光多普勒振动计用于 LDR 频率和相应的振型验证。研究了频谱、LDR 频率下的模态、最佳波冲击角度、效率和声音方向性模式，发现角度θ、φ = 10°、30° 对应于声波激励的最佳方向。此外，发现全声学系统比部分声学系统（即接触激励的系统）更有效。该方法可用于利用长距离非接触激励来检查大型结构。