主动激励声波在后张法混凝土传播机理可视化及影响研究

Visualization of the propagation mechanism and study on the influencing factors of active excitation acoustic waves in post-tensioned concrete structures

当激振器作为主动激励信号时,不同的激励频率和激励幅值的声波在后张法混凝土结构内的传播机理及影响因素对实际工程提供主动激励信号波形参数选取及声发射传感器布置方式具有重要意义。该文利用COMSOL数值模拟方法可视化了激振器激励声波在后张法混凝土梁内的传播机理,提出了激振器主动激励信号波形参数确定的方法。结果表明:数值模拟方法可视化了激振器激励声波在后张法混凝土结构内的传播路径;构建了不同激励频率和激励幅值声波在后张法混凝土结构内衰减模型,可作为稳定的主动激励信号波形参数选取和声发射传感器布置方式的理论基础,当激励幅值相同,激励频率为10 kHz时,激励声波在后张法混凝土结构内衰减系数最小,实际工程中为保证信噪比,较大的激励幅值更有优势。

Clarifying the propagation mechanism and influencing factors of sound waves with different excitation frequencies and amplitudes in the post-tension concrete structure are of great significance for the selection of waveform parameters of active excitation signals caused by a vibration exciter and the determination of the arrangement of acoustic emission sensors in practical projects.The propagation mechanism of excitation acoustic waves caused by the vibration exciter in post-tension concrete beams was visualized by the method of COMSOL numerical simulation,and a method for determining the waveform parameters of active excitation signals was proposed.The results show that the numerical simulation method can realize the visualization of the propagation path of the acoustic wave in the post-tension concrete structure.The attenuation models of acoustic waves with different excitation frequencies and amplitudes in the structures were constructed,which can be used as a theoretical basis for the stable active excitation signal waveform parameter selection and acoustic emission sensors arrangement.When keeping the same excitation amplitude,at 10 kHz excitation frequency,the attenuation coefficient of excitation acoustic waves in post-tensioned concrete structures is the smallest,and in order to ensure the signal-to-noise ratio,larger excitation amplitude is more advantageous in practical engineering.