Basic Research On Stress Relaxation Monitor Of Conductive Polymer Composite

Flexible pressure sensor is a kind of broad application prospects of the new sensor. The composite material of its sensitive components has piezoresistive time variability, so the sensor accuracy is severely reduced. Therefore it is necessary to quantitatively study this material time dependence of the piezoresistive effect. Through measuring composite’s resistance relaxation achieve its stress relaxation. The impact of stress relaxation was eliminated without affecting the flexibility of sensor, so the research has important significance.In this thesis, an algorithm of resistance-stress conversion was designed, which can realize stress relaxation monitoring with using the law of the initial stress relaxation of composite and loading speed on the relaxation process. The main tasks of this paper is as the following tips:(1) the "sandwich" type composite was designed and prepared,which made by useing silicone rubber specimens filled with carbon nanotube.(the mass ratio is 0.04; 1,0.08:1 and 0.12:1);(2) The experiments was performed with the composite compression stress relaxation (loading stress 0.2MPa～0.4MPa, loading speed 0.1 mm/min-5mm/min), obtaining the relationship of resistance, stress, strain with the time;(3) The relationship of resistance-stress-strain-time was quantitative researched in loading and the stress relaxation process.Besides, the relationship of the ratio of carbon nanotubes and silicone rubber, the initial stress relaxation, the loading rate on the above characteristics;(4) Design resistance-stress conversion algorithm based on the rule of resistance and stress relaxation;(5) The relationship between the internal structure of composite and the macroscopic resistance during the process of compression stress relaxation was qualitatived.In this thesis, the laws of composites’ resistance and stress in the process of loading and stress relaxation process was achieved by analyzes, and the composite conductive mechanism was initially derived. The stress relaxation measurement was achieved by the new designed resistance-stress conversion algorithm, and the relative error in the measurement of stress relaxation is less than 9%. This paper analyzes...