基于强度型光纤传感器的声波隔体探测关键技术研究

Research of Acoustic Sounding Sensors over Obstructs Based on Reflective Intensity Modulated Fiber-Optic Sensor

利用反射式强度调制型光纤传感器进行间隔固体介质的声波隔体探测,研制了光纤传感声探测装置,重点从光强调制、振动提取和拾振耦合三个方面研究了在声波隔体探测过程中的振动传递机理,对振动传递过程进行了分析研究,从理论上建立了固体介质、探测拾振装置和光纤敏感单元三者的振动传递数学模型。在此基础上设计实现了光纤声传感系统,并给出了声波隔体探测的实验方法。其结果表明,在5cm厚木板、5cm厚水泥预制板、12cm厚砖墙、10cm厚水泥预制板的测试条件下,此系统对频率为1kHz,声级(SPL)为94dB的标准声信号的探测失真度均小于8%。

Reflective intensity modulated fiber-optic sensors （RIM-FOS） have received increasing attention in the fields of civil engineering for their superior ability of explosion proof, immunity to electromagnetic and high accuracy, especially fitting for measurement applications in harsh environment. A novel functioning prototype of an integrated sensor based on RIM-FOS which is used for acoustic sounding over obstruct is introduced. It aims at the integration of optical fibers based sensors into functional probe for extending the capabilities of the portable solutions for the acoustic detection over solid obstructs. According to the laws of wave propagation, the mechanism of acoustic wave transmission between solid medium and acoustic sounding probe is studied and the calculating formula reflecting the wave transfer process was presented. Some details and overview regarding our ongoing efforts are provided. The experimental results show that the developed sensor′s response distortions towards 1 kHz 94 dB sound pressure level （SPL） signal are all lower than 8% in 4 experimental terms including 5 cm wood board, 5 cm concrete prefabricated board, 12 cm brick well and 10 cm concrete prefabricated board.