Structure bolt tightening force and loosening monitoring by conductive MXene/FPC pressure sensor with high sensitivity and wide sensing range

Mxenes can be used in a variety of applications due to their multifunctional chemical properties. It has received increasing attention as a piezoresistive sensor. However, the stability and pressure monitoring range of the reported MXene sensors are limited, thereby limiting these scalability and effectiveness. In contrast, this paper presents a conductive MXene/FPC based pressure sensor overcomes the aforementioned shortcoming in that its pressure monitoring range and stability are improved by one order of magnitude. Therefore, this study aims to validate the use of MXene sensor for detecting bolt loosening. First, the mechanical properties of MXene were tested, including pressure test, vibration test and so on. The mechanical parameters of MXene are obtained. Secondly, the bolt structure embedded with MXene sensor is tested by torque loading and bolt looseness monitoring under vibration environment. The experimental results show that it has a linear pressure monitoring range of 0-120Mpa, the sensitivity of the sensor is up to 1.3 Mpa(-1), and can remain stable after more than 63,000 cycles. Through monitoring the change of resistance Delta R/R-0, the pressure of bolt pre tightening force transmitted to the joint surface can be accurately sensed. In the vibration environment, when the excitation frequency is 20 Hz, the bolt structure resonates, and Delta R/R-0 increases from 0.28 to 0.6; when the bolt looses in about 100 s, the Delta R/R-0 increases from 0.3 to 0.68 indicates that MXene can respond to bolt loosening in time. Thus, the sensor can be used in the whole life health monitoring of bolted structure completely. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study presents a conductive MXene/FPC based pressure sensor that significantly improves the monitoring range and stability, overcoming the limitations of traditional MXene sensors. Experimental results demonstrate the effectiveness and reliability of using MXene sensors for detecting bolt loosening in real-time under various conditions.