A review on properties, types and applications of auxetic structures

Metamaterials are materials that exhibit unusual properties. Auxetic materials, as a class of metamaterials, are structures with a negative Poisson ratio. These materials become thicker when applied under tensile stress, unlike conventional materials, in the perpendicular direction to the applied force, and become thinner when applied under compressive stress. Auxetic behavior is an independent property that can be obtained from microscopic or macroscopic levels and even molecular or cellular levels. Many structures and materials are known of this feature. This unique feature has created potential applications in the military, aerospace, medical and intelligent sensors, and many other industries. However, there are still many problems with the widespread use of these structures. This paper provides a comprehensive review of these structures that have unique properties and applications of auxetic materials. In addition, some of the latest developments in these materials are described. Materials with a negative Poisson ratio have great potential in various applications such as lightweight structures or biomaterial applications.