Effect of Metastructure Design on the Performance of Pressure Sensors

Abstract

Pressure sensors have been used in devices that require accurate and stable pressure measurements for reliable operations. Metastructure-based pressure sensors (MBPS) have the potential to achieve higher sensitivity and broader sensing range with greater design flexibility and lower weight. Currently, additive manufacturing (AM) has enabled rapid prototyping of high-resolution metastructures at small scales. Deposition of a conductive coating layer on the metastructure can effectively introduce electrical conductivity in MBPS. However, the coupling between the electrical response and the mechanical properties of the metastructure remains unknown. It is not clear how the metastructure design can affect the performance of pressure sensors. In this work, a set of octet-truss cubic metastructures with different unit cell numbers are modeled and fabricated. The sensitivity and sensing range of each metastructure design are predicted from the coupled mechanical-electrical finite element model, the analytical model and the in-situ compression-resistance test, respectively. It is found that increasing unit cell number leads to decreased nominal resistance and enhanced sensing range. But the improvement of sensitivity is limited when the unit cell number exceeds a threshold value. The computational and experimental approaches developed here can be applied to other MBPS with different metastructure configurations and material selections.