A Data-Driven Comparison of Resistive-Viscoelastic Models for a 3D-Printed Conductive Solid

Conductive polymer composites with piezoresistive properties have found extensive use in force sensing applications, such as strain gauges. Polylactic acid filled with carbon black nano-fillers is one such easily available and inexpensive material. The piezoresistive properties of conductive polymers have been shown to share an equivalence with the linear viscoelastic relationship between stress and strain. In this study, we examine six progressively complex resistive-viscoelastic models based on this relationship. After empirically determining the model parameters, we compared their stress prediction outputs using resistance data as input, which had been recorded while subjecting a 3D-printed conductive solid to a compressive force. We observed the model performances for two cases: when model parameters are determined from the complete test cycle and when they are determined phase-wise. Phase-wise coefficients showed a much better prediction accuracy and it was also observed that simpler models gave a better performance than more complex models.