Pressure Sensors Developed Using Auxetic Structures
Authors: Yang Brandon , Lee Dongchan , Wang Huaxia , Yang Chulho 
Published: February 2024

Abstract
Auxetic structures have shown great potential in the development of pressure sensors, owing to their unique mechanical properties. Such structures exhibit a negative Poisson’s ratio due to controlled deformations in the opposite lateral direction to that of typical materials.
This article aims to explore the potential applications of auxetic structures in pressure sensors, their mechanical properties, and the manufacturing techniques employed. Additive manufacturing has facilitated the creation of auxetic structures by enabling the controlled deposition of materials layer-by-layer. The use of computer-aided design (CAD) software allows for the creation of complex and customizable structures with high accuracy and precision. Various types of auxetic structures have been developed, including re-entrant, chiral, and honeycomb structures, among others. These structures have been investigated for their mechanical properties, such as energy absorption, shock resistance, and impact resistance.
Pressure sensors are widely used in various fields, including automotive, aerospace, and medical industries, to measure and monitor pressure changes. Especially, these developed sensors are to obtain the pressure profile of a human body against car seats for safety and health monitoring of the passengers for autonomous vehicles. These sensors will be used in conjunction with the Super-Resolution Generative Adversarial Network (SRGAN) and Kriging-based Grid-less Design Methods. Auxetic structures are well-suited for this application due to their unique mechanical properties. It has been found that stresses in the part are concentrated in uniform areas, making it an ideal location for a strain gauge, which is an essential component of pressure sensors. Moreover, studies have shown that auxetic meshes have increased energy absorption properties alongside the ability to dampen external vibrations, which would be ideal for this application, minimizing the interference with the sensors. Additionally, due to the increased density and shrinking cross-sectional area under compression, an auxetic structure can exert a more concentrated pressure, which can be ideal for maintaining higher resolution in smaller pressure sensors. Simulation studies using finite element analysis (FEA) have shown that a re-entrant mesh has a more concentrated stress with a higher maximum compared to the hexagonal mesh, making it a suitable candidate for pressure sensor applications. In the manufacturing of pressure sensors, conductive filaments are used to print strain gauges in the auxetic mesh. This creates a basic pressure sensor with a larger range than non-auxetic meshes.
In conclusion, the development of auxetic structures has opened up new possibilities in the field of pressure sensors. The unique mechanical properties of auxetic structures, including their negative Poisson’s ratio, energy absorption, and ability to dampen external vibrations, make them an ideal candidate for pressure sensor applications. The use of 3D printing technology enables the creation of complex and customizable structures with high precision and accuracy, making it a promising avenue for the future development of pressure sensors. Further research is required to investigate the full potential of auxetic structures in pressure sensor applications and to optimize their mechanical properties for specific applications.