Inspection of incipient structural damage is of great significance. Existing techniques based on nonlinear guided waves have shown great promise for the detection of incipient damage due to material microstructure changes, but with only limited success for damage localization, which is technically more challenging. Our previous work uncovered the existence of the second harmonic A0 mode Lamb waves in a PZT-driven system, as a result of the mixing of the primary A0 and S0 mode Lamb waves, thus pointing at the possibility of performing damage localization through tuning the size of the wave mixing zone. In the present study, a two-dimensional incipient damage localization method is proposed based on this newly discovered wave phenomenon. By visualizing the nonlinear wave field, damage-induced nonlinear wave scattering features are first investigated. A dedicated localization algorithm is then proposed and evaluated. Numerical results show that the energy of the scattered nonlinear wave is mainly confined to a narrow region along the actuator-damage path, the spatial variation of which can be approximated by a simple Gaussian function. Embedding this information into the proposed localization strategy, damage localization can be achieved using a simple physical system. Experiments are finally carried out to validate the 2nd A0 wave scattering features and the proposed damage localization method.

早期结构损坏的检查具有重要意义。基于非线性导波的现有技术在检测由于材料微观结构变化引起的初始损伤方面显示出巨大的潜力，但在损伤定位方面取得的成功有限，这在技术上更具挑战性。我们之前的工作揭示了 PZT 驱动系统中二次谐波 A0 模式兰姆波的存在，这是由于初级 A0 和 S0 模式兰姆波混合的结果，因此指出了通过调整尺寸进行损伤定位的可能性波混合区。在本研究中，基于这种新发现的波浪现象，提出了一种二维初始损伤定位方法。通过可视化非线性波场，首先研究了损伤引起的非线性波散射特征。然后提出并评估专用的定位算法。数值结果表明，散射非线性波的能量主要局限于沿致动器损伤路径的狭窄区域，其空间变化可以通过简单的高斯函数近似。将此信息嵌入到建议的定位策略中，可以使用简单的物理系统实现损伤定位。最后进行实验以验证第二个 A0 波散射特征和提出的损伤定位方法。将此信息嵌入到建议的定位策略中，可以使用简单的物理系统实现损伤定位。最后进行实验以验证第二个 A0 波散射特征和提出的损伤定位方法。将此信息嵌入到建议的定位策略中，可以使用简单的物理系统实现损伤定位。最后进行实验以验证第二个 A0 波散射特征和提出的损伤定位方法。