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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。
In order to eliminate the unfavorable influence of the standing wave in the ultrasonic heat wave detection on the detection results, the vibration characteristics and the acoustic chaos of the component under the ultrasonic excitation were studied by means of numerical simulation. First, by setting up the finite element model of composite material with cracked damage, the resonance modes of the standing wave of the member under different excitation frequencies are studied. It is found that the response of the member under the harmonic excitation is still harmonic, and the response frequency and The same excitation frequency, easy to produce standing wave resonance. Then, the influence of acoustic chaos on the detection results is analyzed by improving the simulation model. The results show that the generation of acoustic chaos can eliminate the standing wave and improve the surface temperature difference of the composite material under the same excitation frequency. And as the excitation frequency increases, the probability of acoustic chaos phenomenon also increases. The actual testing process, which can improve the detection conditions to improve detection capabilities.