Auxetic Materials for Personal Protection: A Review

Abstract

Life‐changing illnesses and fatalities caused by inefficient personal protective clothing and equipment are increasing day by day. The discrepancy between the test standards, environmental conditions, and infield collision is the reason why personal protection equipment and clothing have not yet decreased the number of injuries in various fields such as military and sports. To further increase the efficiency of personal protection materials, auxetic materials are suggested because of their high energy absorption, good permeability, form‐fitting ability, and high indentation resistance. Auxetic materials are nonconventional materials with a negative Poisson's ratio and can shrink under compression and expand when subjected to stretching. In comparison to nonauxetic conventional materials, auxetic materials have improved properties that can be useful for personal protection applications. This review focuses on the importance of auxetic materials for personal protection, focusing on reducing the chances of injury and what possible ideas can further benefit the protection products. The first part of the review discusses the auxetic structures and their protection applications followed by the fabrication of auxetic structures. The review will conclude with limitations, economic prospects, and what possible work can further improve the potential use of auxetic materials in personal protection.

Auxetics and Other Systems with Unusual Characteristics

“…The authors discuss reduction of injury probability and some ideas which can further benefit protection products. [ 14 ]…”

A finite element analysis of auxetic composite fabric with rotating square structure

“…Due to the unique deformation behavior and energy absorption ability, auxetic materials have demonstrated great potential applications in perfect-fitting clothing, protective equipment, high-performance footwear, high-sensitivity transducers, soft robots, wearable devices, and even aircraft components, etc. [22][23][24][25][26] The exploitation of auxetic materials largely depends on the understanding of their internal structures. According to the monographs, [27][28][29] re-entrant cells, rotating polygons, chiral/anti-chiral lattices, nodule-fibril models, missing-rib models, and those with elastic instability are among the most typical geometrical structures that can achieve auxetic behavior.…”

Metamaterials with Poisson's ratio discontinuity by means of fragmentation–reconstitution rotating units

“…The problem of indentation is crucial for the impact behaviour of structures. For a comprehensive overview of auxetic materials and metamaterials, the reader is referred to some recent reviews [23,[35][36][37][38][39][40][41][42][43][44][45][46][47] and monographs [48][49][50][51][52], which not only elucidate the various micro-lattice geometries that give rise to auxetic behaviour but also contain exhaustive literature reviews. Among the various microstructural geometries, one of the earliest types of auxetic systems is that of rotating rigid units.…”