Impact localization of composite laminates based on weight function compensation localization algorithm of thin film sensors

Composite structures are sensitive to impact damage in practical engineering.Electric resistance change method(ERCM)is an ideal technique for damage monitoring of composite structures.Due to the anisotropy of fiber-resin matrix composites,impact location monitoring is difficult,and research on impact location of fiber composite laminates(FRPs)is limited.A preparation method of MXene/CNT/CuNps thin film sensor is proposed.According to the modeling simulation and theoretical calculation,the resistance change characteristics of the thin film sensor are obtained,the relationship between the impact distance and the resistance change is established,and the sensor array is designed.A three-point localization algorithm and a weight function compensation localization algorithm are proposed,which can improve the imaging accuracy of the impact position.The impact point location was observed and analyzed using ultrasonic C-scan technology.The results show that the weight function compensation positioning algorithm can accurately locate the impact of the composite structure,and the error in the X direction is 7.1%,the error in the Y direction is 0.03%,which verifies the effectiveness of the method.

Vibration monitoring for composite structures using buckypaper sensors arrayed by flexible printed circuit

Fiber-reinforced resin-based plastics are widely used in structural composites for aerospace and automotive applications,and they often face extreme load conditions in actual working environments.It is challenging to monitor the damage of the structure during the vibration process.This study was aimed at using buckypaper(BP)sensors to monitor the structural health status of composite structures under ambient vibrations.First,the feasibility of flexible printed circuit instead of wire is verified by the tensile experiment.Then the vibration monitoring experiment of the composite cantilever beam is carried out by using BP sensors systematically.The sweep frequency experiment determines the excitation frequency of the cantilever beam.Low-period vibration fatigue cycle and high-period vibration fatigue cycle experiments are designed to verify the vibration monitoring method using BP sensors.Besides,the signal response of BP sensors in the vibration experiment is analyzed,and the relationship betweenΔR/R0 and vibration acceleration is obtained.Finally,through the change law ofΔR/R0 of the sensor,the cumulative damage caused by vibration fatigue is visualized.It is demonstrated that the monitoring method based on BP sensors can be applied to study the damage behavior of composite structure under the vibration environment.