无参考Lamb波相控阵结构损伤监测成像方法

超声相控阵结构健康监测中通过计算差信号获取损伤散射信号的方法易受环境和结构变化的影响，针对这一问题，提出无参考信号的相控阵结构健康监测成像定位方法。采用窗函数截取散射信号，剔除直达波和边界反射信号。基于相控阵方法，对结构损伤状态时的传感器响应信号进行处理，无需结构健康状态时传感信号作为参考。该方法在碳纤维复合材料板结构上的实验研究证明，采用无参考信号的超声相控阵方法能够精确实时地监测并清晰表征结构损伤；同时，该方法可以大大缩短监测时间，且不受环境条件变化的影响，为该方法的工程化应用奠定基础。

Baseline-free Lamb wave phased array imaging method for structural damage monitoring

In the ultrasonic phased array structural health monitoring method, the damage scattering signal gotten by comparing the damage structural response signal with the health structural response signal can be affected easily by some external factors, such as, environment and the change of the structure. In order to solve this problem, the baseline-free phased array damage identification imaging method was proposed. The window function was used to get the damage scattering signal and to exclude the direct propagation wave and the reflection wave from the structural boundaries. Based on the phased array theory, the response signals travelling in the damage structure could be used to realize the damage recognition, and the health structural response signals no longer act as the reference signal in the calculation procedure. Experiments on the carbon composite structure show that the damage in the structure can be recognized precisely by using the baseline-free phased array method. The method does not need the baseline signal. It can greatly shorten the monitoring time and is not affected by the change of the environment and the structure. This research is the foundation of the engineering application for the method.