Benchmarking Electrical Resistance Measurement Methods for Piezoresistive 3D-Printed Polymer Composites

Accurate measurement of electrical resistance is a critical requirement in the characterization of piezoresistive polymer composites, particularly when resistance variations induced by mechanical deformation are small relative to the nominal resistance value. This challenge is especially relevant for conductive polymers produced by additive manufacturing (AM), where contact resistance, material anisotropy, and process-induced variability can significantly affect measurement reliability. This paper presents a methodological review and benchmarking of electrical resistance measurement techniques applicable to piezoresistive 3D-printed polymer composites. Classical approaches, including two- and four-point measurements, Wheatstone bridge configurations, and Kelvin-based techniques, are reviewed and compared in terms of accuracy, sensitivity, robustness to parasitic resistances, and experimental complexity. Beyond conventional methods, the paper discusses the potential of recent and emerging measurement strategies, such as advanced bridge configurations, digitally assisted techniques, and hybrid analog–digital approaches enabled by modern data acquisition systems and embedded electronics. Although not exhaustively implemented, these approaches are considered to frame current trends and future directions in high-resolution resistance measurement for self-sensing materials. Analytical formulations and circuit-level models are employed to describe the operating principles of the reviewed methods, supported by simplified electrical simulations using accessible electronic circuit simulators. In parallel, a concise overview of commercially available measurement hardware—including precision source–measure units, data acquisition systems, and instrumentation amplifiers—is provided to contextualize practical implementation choices. The comparative analysis indicates that the four-point measurement method constitutes a robust and practically viable reference approach for detecting small resistance variations in conductive AM polymers within typical laboratory constraints. Rather than establishing a definitive hierarchy among techniques, this work positions the four-point method as a justified baseline for comparison. Overall, the proposed benchmark combines theory, simulation, and hardware considerations, offering practical guidance for experimental design while leaving scope for future investigation of emerging measurement techniques and recent developments in resistance sensing for self-sensing AM materials.