基于声压测量的结构模态参数识别研究

为克服接触式测量传感器附加质量的影响,本文采用非接触式声压测量获取结构近场的辐射声压信号,提出Hilbert-Huang变换二次滤波时频分析方法对非平稳的近场声压辐射信号进行分析,实现了在强噪声环境中对桥梁结构模态参数的识别。在实验室对一跨径为11.2m的H型简支钢梁开展试验,结果表明：该方法能准确识别钢梁的前3阶固有频率,平均误差在0.5%以内,并成功获取结构的模态振型。该方法为桥梁结构模态参数获取和结构健康监测提供新的手段。

Experimental Study on Modal Parameter Identification of Bridge Structure Based on Non-contact Sound Pressure Measurement

In order to overcome the influence of the additional mass of the contact measurement sensor, the non-contact sound pressure measurement is used to obtain the radiated sound pressure signal of the structure in the near field, and the Hilbert-Huang transform secondary filtering analysis method is proposed. This method can effectively process the non-stationary sound pressure signal, identify the modal parameters of the structure from the noise environment and realize the identification of bridge modal parameters by using sound pressure signal. In the laboratory, the dynamic test of an H-shaped beam with a span of 11.2m was carried out. The result shows that this method can quickly and accurately obtain the first three natural frequencies of the beam, and the average error is less than 0.5%. On the basis of obtaining the natural frequencies of the structure, the modal shape of the structure is successfully identified. This method provides provide new ideas and methods for bridge structural dynamic parameter testing and structural health monitoring.