A Study On The Sensitivity Of Conducting Fiber Temperature/strain Sensing Based On Textile Structure

The conducting fiber based on textile structure was designed for solving large strain under high temperature in this paper. This thesis includes three parts: the first part is the study on circuit network of conducting fiber based on textile structure. The second part is the study on the relationship between the resistance of the CF yarn and fabric and the temperature. The third part is the study on the response of the resistance of CF yarn fabric to the strain under certain temperature, the resistance response of CF yarn fabric with temperature and strain changing and the CF yarn fabric measured simultaneously by temperature and strain.Firstly, the study situation of smart fiber and smart textile were reviewed. Then, the purpose and significance of the thesis were described; also, the main research content, innovation point, emphasis and difficulty were introduced.To study the mechanism of the response of the resistance of the stainless steel yarn fabric and CF yarn fabric to the strain, we firstly analyzed and simulated single loop of knitted fabric including two long resistances R1 and R2 and one contact resistance Rc. We analyzed the resistance of single loop with the strength changing. Second, we simulated the circulate network of the fabric and calculated the equivalent resistance of the fabric. We used MATALAB language to calculate the equation because the required solution of the equation was more complex. The situation of the theoretical values of SS yarn fabric and CF yarn fabric was the same trend with the experimental values, which indicated the strain sensing mechanism was mainly caused by the contact resistance between the yarns.The CF fabric was designed for solving the difficulty problem of large strain under high temperature. It was obtained that the resistance of CF yarn fabric was affected by temperature. It was found that the resistance of CF yarn decreases linearly with increasing temperature. The resistance of CF yarn fabric decreases with increasing temperature, which becomes a linear relationship within certain range. The mechanism of the resistance of CF yarn fabric with changing temperature is that the resistance of the fabric mainly caused by the contact resistance between the yarns. By the experiments and analysis, it is proved that the CF yarn knitted structure can be used to measure the high temperature.To explore the response of the resistance of CF yarn fabric with temperature and strain, we firstly stretched CF yarn fabric into different maximum strains at certain temperature. The differences in resistance of different cycles decrease with increasing. The repeatability of the fabric is good. Secondly, the resistance response of CF yarn fabric with simultaneous changing of temperature and strain was studied. It was obtained that the resistance decreases as temperature and strain increase. The repeatability of the fabric becomes good as cycle time increases. Finally, we used temperature compensation technology into achieve the sensor of CF yarn fabric simultaneously measure by temperature and strain.