A non-destructive testing procedure is proposed for damage detection in composites using full wavefield measurement obtained using a scanning laser Doppler vibrometer. Vibrations are excited using two low-power piezoelectric actuators leading to nonlinear elastic wave modulation at the defect. One actuator is supplied with a broadband chirp signal and the other actuator is supplied with a single-frequency sine signal. First, a time–frequency filtering method is proposed to extract specific nonlinear components of interest (e.g. second higher harmonic and first modulation sideband) without the need for multiple excitation sequences. Next, damage maps are constructed using broadband bandpower calculation of the filtered nonlinear components. It is demonstrated that the modulation sidebands provide an exclusive imaging of defect nonlinearity, and are not affected by potential source nonlinearity. The proposed damage map construction procedure is applied for various carbon fiber reinforced polymer test specimens with different damage features: (1) coupon with quasi-static indentation damage, (2) coupon with artificial delaminations, (3) bicycle frame with impact damage, and (4) stiffened aircraft panel with partially debonded stiffener. The obtained results indicate the high performance of the developed procedure for detection of various defect types in curved and/or stiffened carbon fiber reinforced polymer components.

提出了一种无损检测程序，用于使用扫描激光多普勒振动计获得的全波场测量结果来检测复合材料中的损伤。使用两个低功率压电致动器激励振动，从而在缺陷处产生非线性弹性波调制。一个执行器被提供一个宽带线性调频信号，另一个执行器被提供一个单频正弦信号。首先，提出了一种时频滤波方法，无需多个激励序列即可提取感兴趣的特定非线性分量（例如，二次高次谐波和第一调制边带）。接下来，使用滤波后的非线性成分的宽带带宽计算来构建损伤图。结果表明，调制边带提供了缺陷非线性的唯一成像，并且不受潜在来源非线性的影响。拟议的损伤图构建程序适用于具有不同损伤特征的各种碳纤维增强聚合物试样：（1）具有准静态压痕损伤的试样；（2）具有人工分层的试样；（3）具有冲击损伤的自行车车架；以及（4）用部分去粘的加劲肋加劲的飞机面板。所获得的结果表明，所开发程序的高性能，可以检测出弯曲和/或硬化的碳纤维增强聚合物组件中的各种缺陷类型。（2）带有人工分层的试样，（3）受到冲击破坏的自行车车架，以及（4）带有部分去粘的加劲肋的加劲的飞机面板。所获得的结果表明，所开发程序的高性能，可以检测出弯曲和/或硬化的碳纤维增强聚合物组件中的各种缺陷类型。（2）带有人工分层的试样，（3）受到冲击破坏的自行车车架，以及（4）带有部分去粘的加劲肋的加劲的飞机面板。所获得的结果表明，所开发程序的高性能，可以检测出弯曲和/或硬化的碳纤维增强聚合物组件中的各种缺陷类型。