Department of Environment, Land, and Infrastructure Engineering (DIATI), Politecnico di Torino, 10129 Turin, Italy.
Sensors (Basel). 2023 Mar 16;23(6):3188. doi: 10.3390/s23063188.
We focus on the design, optimization, fabrication, and testing of fiber Bragg grating (FBG) cantilever beam-based accelerometers to measure vibrations from active seismic sources in the external environment. These FBG accelerometers possess several advantages, such as multiplexing, immunity to electromagnetic interference, and high sensitivity. Finite Element Method (FEM) simulations, calibration, fabrication, and packaging of the simple cantilever beam-based accelerometer based on polylactic acid (PLA) are presented. The influence of the cantilever beam parameters on the natural frequency and sensitivity are discussed through FEM simulation and laboratory calibration with vibration exciter. The test results show that the optimized system has a resonance frequency of 75 Hz within a measuring range of 5-55 Hz and high sensitivity of ±433.7 pm/g. Finally, a preliminary field test is conducted to compare the packaged FBG accelerometer and standard electro-mechanical 4.5-Hz vertical geophones. Active-source (seismic sledgehammer) shots are acquired along the tested line, and both systems' experimental results are analyzed and compared. The designed FBG accelerometers demonstrate suitability to record the seismic traces and to pick up the first arrival times. The system optimization and further implementation offer promising potential for seismic acquisitions.
我们专注于设计、优化、制造和测试光纤布拉格光栅（FBG）悬臂梁加速度计，以测量外部环境中主动震源的振动。这些 FBG 加速度计具有许多优点，例如多路复用、抗电磁干扰和高灵敏度。介绍了基于聚乳酸（PLA）的简单悬臂梁加速度计的有限元法（FEM）模拟、校准、制造和封装。通过 FEM 模拟和振动激励器的实验室校准讨论了悬臂梁参数对自然频率和灵敏度的影响。测试结果表明，优化后的系统在 5-55 Hz 的测量范围内具有 75 Hz 的共振频率和±433.7 pm/g 的高灵敏度。最后，进行了初步的现场测试，以比较封装的 FBG 加速度计和标准机电 4.5-Hz 垂直地震检波器。沿着测试线采集主动震源（地震雪橇）的激发信号，并对两个系统的实验结果进行了分析和比较。设计的 FBG 加速度计适合记录地震轨迹和拾取首波到时。系统优化和进一步实施为地震采集提供了有前景的潜力。
