Experimental Assessment of Piezoresistive Self-Sensing Capability in 3D-Printed Conductive PLA Specimens

Additively manufactured conductive polymers enable the development of material specimens with an intrinsic sensing capability, where mechanical loading can be inferred directly from electrical response without the use of discrete sensors. Among these materials, carbon-filled conductive polylactic acid (PLA) filaments provide a low-cost and accessible platform for exploring piezoresistive self-sensing concepts at the material level. This work presents an experimental assessment of the piezoresistive self-sensing capability of 3D-printed conductive PLA specimens manufactured by material extrusion. Standard tensile specimens were produced and subjected to uniaxial loading using a universal testing machine, while the electrical resistance was monitored simultaneously during mechanical deformation. The experimental study focuses on verifying the existence, stability, and repeatability of the electromechanical response within the elastic deformation regime. The results reveal a clear and consistent correlation between applied mechanical loading and electrical resistance variation, with resistance changes closely following the imposed deformation cycles. This behavior confirms that the printed conductive PLA specimens exhibit a stable piezoresistive response suitable for strain-dependent signal acquisition at the material level. Rather than pursuing a comprehensive material characterization, this study provides a proof of concept demonstrating the feasibility of using 3D-printed conductive PLA specimens as self-sensing material elements. The findings contribute experimental evidence supporting the use of additively manufactured piezoresistive polymers as embedded sensing media in future mechanically loaded components and robotic structures.