This paper presents a study on nonlinear elastic wave modulation due to an applied periodic thermal field. The experimental study is performed with a thermal analogy of the vibro-acoustic wave modulation (VAM) technique. The aim is to identify sources of nonlinear effects appearing in the response signal of a damaged structure. Assigning specific nonlinear effects to their corresponding sources is a key challenge for most nonlinear acoustic methods. Separation of nonlinear effects into those related to damage dynamics and those related to other sources, e.g., material nonlinearity or boundary conditions, is very important for practical applications of nonlinear acoustic methods.

In this study, an aluminum plate with a localized fatigue crack is investigated. The plate is excited simultaneously with a high-frequency acoustic wave and a low-frequency thermal field generated by a modulated laser source. The response vibration signal is acquired at different locations (near and far from the damage) using a Laser Doppler Vibrometer (LDV). Signal processing is applied to extract the nonlinear effects in the form of modulation sidebands.

本文介绍了由于施加周期性热场而引起的非线性弹性波调制的研究。实验研究是通过热模拟振动声波调制（VAM）技术进行的。目的是识别出现在受损结构的响应信号中的非线性效应的来源。对于大多数非线性声学方法，将特定的非线性效果分配给其相应的源是一项关键挑战。对于非线性声学方法的实际应用，将非线性效应分离为与损伤动力学有关的效应和与其他来源（例如，材料非线性或边界条件）有关的效应是非常重要的。

在这项研究中，研究了具有局部疲劳裂纹的铝板。板同时由调制激光源产生的高频声波和低频热场激发。使用激光多普勒振动计（LDV）在不同的位置（接近和远离损坏）获取响应振动信号。应用信号处理以提取调制边带形式的非线性效应。