Additively Manufactured Mechanical Metamaterial‐Based Pressure Sensor with Tunable Sensing Properties for Stance and Motion Analysis

Abstract

Mechanical metamaterials are attracting considerable attention due to their unique properties not found in natural materials. Advanced geometrical shapes such as Menger cubes, origami templates, and gyroids offer exciting avenues for device engineering. In addition, the recent developments of various additive manufacturing technologies have expanded materials selection and geometrical complexities. Herein, a piezoresistive pressure sensor based on a 3D‐printed gyroid structure with a conformal coating of carbon nanotubes (CNTs) is presented. The gyroid structures are printed using fused deposition modeling (FDM) 3D printing with thermoplastic polyurethane (TPU), providing mechanical robustness even at low densities. By altering the relative density of the gyroid structure, Young's modulus can be tailored, ranging from 0.32 MPa at 30% relative density and 3.61 MPa at 80% relative density. The presented gyroid‐based pressure sensor achieves a wide sensing range of up to 1.45 MPa and a high sensitivity of 2.68 MPa−1. The sensor is integrated into a shoe for wearable applications, demonstrating its mechanical robustness and potential for human stance and motion monitoring.

Novel additively manufactured dihedral tiling architected metamaterial conformed with pentagon and rhombus: design and mechanical properties

“…Compared to the variable-oriented concentric struts in the dihedral structure, the periodic and well-organized geometry of the latter may be the main factor for enhanced stiffness, with a factor of approximately 2.5 and 6.6 times higher for the vertical and horizontal orientations, respectively. On the other hand, metamaterials with topology such as TPMS Gyroid [35] or Arc-Based Peanut [14] were found to be more flexible within the same range of relative density, around 1.3 and 2 times on average. Meanwhile, the Hilbert-architected topology [10] was approximately 2.7 times stiffer on average.…”

Recent advances of additively manufactured noninvasive kinematic biosensors

“…In addition, the fabricated sensor showed a linear response of up to 37% strain. Due to the programmable density of the sensor, it demonstrated a wide sensing range of up to 1.45 MPa and a high sensitivity of 2.68 MPa (Figure 3A) (Kim et al, 2023).…”

“…By incorporating eight pressure sensors into a sandal, the system could identify different gait postures, including heel Frontiers in Bioengineering and Biotechnology frontiersin.org strike, foot flat, mid stance, heel rise, and toe-off. This sensor setup allowed for a comprehensive analysis of various aspects of gait and posture (Kim et al, 2023). Kim et al manufactured a multi-axis pressure sensor utilizing Fused Filament Fabrication (FFF) 3D printing technology.…”

Output Enhancement of a 3D‐Printed Triboelectric Nanogenerator Using Laser Surface 3D Patterning

“…It also highlighted the development of self-powered sensors that utilize 3D printing technology. [15][16][17] Further research has been conducted focusing on creating an optimized 3D-printed TENG by patterning, [18] and the creation of a flexible, 3D-printed triboelectric-piezoelectric hybrid nanogenerator. [13] Additional studies delving into various materials, architectures, and applications broaden the potential of 3D printing in TENGs and pave the way for the creation of effective, innovative, and sustainable TENG systems.…”