Additive manufacturing for layered piezoelectric structures with directional sensing capability

Abstract Additive manufacturing (AM) enables the integration of multiple materials into architected designs with tailored functional material performance. In this work, modular layered structures composed of barium titanate (BTO) and polylactic acid (PLA) were fabricated using direct ink writing and fused filament fabrication to investigate compressive properties and directional piezoelectric sensing. Mechanical testing indicated that bulk BTO demonstrated high stiffness but was prone to brittle failure. In contrast, PLA exhibited ductile behavior with lower strength. However, the layered PLA-BTO structure achieved an optimal balance between strength and strain tolerance, facilitated by interlayer sliding and stress redistribution. Cyclic compressive testing conducted under a load of 5 N along the predetermined sensing axis exhibited significant directional piezoelectric selectivity in the layered PLA/BTO structure. This observation underscores the highly anisotropic piezoelectric performance of the structure, with the most pronounced voltage output along the x -axis (approximately 2.2 V), moderate response along the y -axis (approximately 0.9 V), and negligible activity along the z -axis (approximately 0.04 V). This anisotropy sensing capability is attributed to structural segmentation, where PLA layers act as insulating barriers and BTO layers form continuous charge pathways along selected axes. These results highlight the potential of AM-enabled layered architectures for programmable anisotropy, offering pathways toward localized directional sensing and energy-harvesting applications in robotics, aerospace, and structural health monitoring.