A Biomimetic Metal Diaphragm Vibration Sensor with High-Frequency Response Based on a Rigid-Flexible Hybrid Design Strategy

High-frequency weak vibrations are a common occurrence in the operation of mechanical equipment and can convey significant information regarding the status of the equipment, including warnings of potential faults and assessments of performance. However, conventional sensors that employ a single flexible material are constrained by the inherent mechanical properties of the material itself. This results in suboptimal performance, particularly concerning the response frequency bandwidth and the response/recovery time. This study proposes a vibration sensor concept based on a rigid-flexible hybrid design strategy inspired by the structural properties of vibration receptors in biological cracks. The developed sensor employs a femtosecond laser technique to generate a cracked microstructure on a copper metal diaphragm, and a nano silver conductive sensing layer is axially deposited on the PDMS located on its surface by magnetron sputtering. The experimental findings demonstrate that the vibration sensor exhibits an ultrawide frequency response bandwidth and is capable of accurately monitoring vibrations with frequencies up to 1500 Hz. Additionally, it displays excellent linearity (0.97704 in the range of 0–1660 Pa and 0.99182 in the range of 1660–2830 Pa). Furthermore, the experimental findings demonstrate that the designed vibration sensor is not only suitable for speech monitoring and recognition but also has the potential for wide-ranging utilization in vibration monitoring of mechanical equipment. This contributes to the advancement of flexible sensor technology to a more sophisticated level.