中文摘要：

为了消除超声热波检测中的驻波现象对检测结果的不利影响,运用数值仿真方法研究了构件在超声激励下的振动特性和声混沌现象。首先,通过建立含裂纹损伤的复合材料构件的有限元模型,研究了不同激励频率条件下构件的驻波共振模态,发现构件在超声谐波激励下的响应仍是谐波,且响应频率与激励频率相同,容易产生驻波共振。然后,通过改进仿真模型,分析了声混沌对检测结果的影响,结果表明：在相同激励频率条件下,声混沌的产生能够消除驻波,更有助于提高复合材料构件损伤处的表面温差,并且随着激励频率的增加,声混沌现象出现的概率也增加。实际检测过程中,可据此改善检测条件提高检测能力。

英文摘要：

The aim of this paper is to study and solve the disadvantage of standing wave on the damage detection by ultrasonic thermal wave testing technology. The vibration characteristics and acoustic chaos phenomena of the structure under ultrasonic excitation were numerically analyzed. Firstly, by establishing a composites finite model with a crack, the resonance models of the structure under different excitation frequencies were analyzed. It is found that the harmonic wave response of the structure under harmonic ultrasonic wave with the response frequency was equals to the excitation frequency, and the standing wave easily appeared. Then, by improving the composites finite model, the influences on the testing result caused by acoustic chaos were analyzed. The numerical results show that, under the same excitation frequency, the standing wave was effectively eliminated by acoustic chaos. Acoustic chaos is beneficial to the detection by increasing the surface temperature difference at the damage, and the probability of acoustic chaos generated is increased by increasing the excitation frequency. And the detection capability and conditions can be improved according to this result.