A Simplified Physical Model for the Sensitivity–Pressure Relationship in Textile-Based Piezoresistive Sensors

Textile-based flexible pressure sensors have attracted considerable attention in wearable sensing applications due to their good comfort and mechanical compatibility. However, their sensitivity usually exhibits a nonlinear dependence on pressure, while a compact analytical framework with interpretable physical parameters is still lacking. In this work, a simplified physical model based on lumped effective parameters was established based on the evolution of fiber–conductive particle contacts, and an expression describing the sensitivity–pressure relationship was derived. The model indicates that the sensitivity is mainly governed by an electrical parameter α and a mechanical parameter ratio Eb/Ex, and captures the dominant nonlinear decrease in sensitivity with increasing pressure. To verify the applicability of the model, the effects of conductive particle loading, filler type, surface treatment, sensing-layer area, weave structure, and layer number on the sensor response were systematically investigated. In addition, comparison between model-based calculation and experiment in the low- and medium-pressure range gave RMSE values of 0.0040 and 0.0056, and MRE values of 27.6% and 13.4% for the single-layer and four-layer structures, respectively. These results show that the proposed framework captures the main trends of the sensitivity–pressure behavior and provides a physically interpretable basis for discussing how structural and material factors regulate sensor response. This work offers a useful framework for understanding the structure–property relationship of textile-based piezoresistive pressure sensors and may provide preliminary guidance for the design of customized sensors in wearable healthcare and soft robotics applications.