Research On The Characteristics Of Health Monitoring Sensor Based On Carbon Nanotubes For Composites

The polymer composite materials are better than the the material with single component when considering the overall performance aspect.They have been widely used in the fields of engineering,aviation,medical and the others.However,influenced by unfavorable factors such as aging,cracking,corrosion and impact load,the materials are usually prone to be unsafe due to the long-term using.Health monitoring technology has become an important means of monitoring the health status of materials and prolonging their service lives.Traditional ray detection,ultrasonic testing and other off-line detection methods often need to be carried out in the device downtime.With larger volume,the detection equipment can not work in real time.Therefore,it is necessary to study an on-line detection technology that can installed conveniently.The real-time health monitoring method of composite materials is studied using carbon nanotube film as sensing elements in this paper.Firstly,a carbon nanotube film data acquisition system is established.With C8051F060 microcontroller as the core part,the system converts the resistance signal of carbon nanotube film into the voltage signal after excited by the constant current source circuit.The voltage signals are collected by the C8051F060 and transmitted to the PC after processed by the filter circuit,amplifier circuit.Then the film resistance real-time rate of change values are processed through the software programming in PC.Secondly,based on the theory of percolation and Neugebauer-webb,the temperature and strain mechanism models of carbon nanotube films are separately established.Finally,the real-time data acquisition of the thin-film resistor in the experiment is carried out by using the data acquisition system.Furthermore,the temperature characteristics of the sensor,tensile properties and omnidirectional properties are studied.The experimental results show that the carbon nanotube film data acquisition system designed in this paper can collect 9 signals in real time to meet the system design requirements.The temperature mechanism and strain mechanism model established in this paper can be used to analyze the relevant properties of carbon nanotube films.Thereby,the study has laid the solid foundation for the health monitoring with the carbon nanotubes film.