Preliminary Research On Viscoelastic And Flexible Pressure-Sensitive Components

The surface interlaminar stress monitoring is the key to improve the assembly speed of large equipment, ensure it can accurately acquire the system status information. It has great significance in the field of artificial electronic skin, the science and technology of national defense, automobile manufacturing industry, and so on. Carbon nanotubes have excellent conductivity and great length to diameter ratio. For the reason that silicon rubber filled with a handful of carbon nanotubes can form a conductive network, while ensure the flexibility and piezoresistance sensitivity of composite materials, it can be used as flexible pressure sensor. As composite materials is influenced by it’s substrate material, have the viscoelastic, it has a great dependency to the time, the resistance of traditional "sandwiches" structure has great changes under the constant pressure (the resistance changes above35%in1minute), it has a great dependency to the time, which influences sensor precision seriously. The home and abroad has been committed to weaken its time-dependent, for instance, increasing the content of conductive filler or adding other solid particles, but these methods can not work significantly, furthermore, lower the flexibility of the composite materials. This paper presents a new type of structure, make the pressure-sensitive work in incomplete pressure areas, extract signal from different positions, and study it’s characteristics of pressure and resistance, committing to weaken the dependency of resistance-time of composite materials.The main research contents of this paper include the following items:(1) With a certain process design and preparation of viscoelastic and flexible pressure sensitive unit sample. With multi-walled carbon nanotubes for conducting filler, silicone rubber for matrix materials, use co-solution method, assisted with ultrasonic wave and stirring dispersion treatment, with much electrode circuit board as the above and underside of pressure-sensitive components, making the flexible and soft pressure-sensitive components. (2) Design a real-time automatic resistance data collection system, it use C8051F330as the control circuit chip, MAX308as multi-channel analog switch, through the multi-channel analog switch import multi-channel resistance, acquire voltage signal in turn, after analog-to-digital conversion then through a serial port to the PC for data processing save and analysis.(3) Quantitative analysis of the resistance-pressure-time characteristics, and preliminarily qualitative research the pressure and resistance mechanism of pressure-sensitive component.We have prepared four kind of pressure-sensitive unit with four mass rate,0.08:1、0.12:1、0.16:1、0.20:1.The test results show that the resistance changes of structure A、B、C、D less than8%in1minute(0.1-0.5MPa), far less than the resistance change rate of "sandwich" structure,and the resistance increase with the pressure increase,in the case of conductive network fully restore(each cycle unload1500seconds), repeatability errors less than15%.