Shear thickening fabric composites for impact protection: a review

Fabrics with proper mechanical properties and high structural designability are frequently selected as the reinforcement of flexible composites. Shear thickening materials (STMs), including shear thickening fluid and shear thickening gel, are dense colloidal suspensions exhibiting an abrupt increase in viscosity with increasing shear rate. Shear thickening fabric composites (STFCs) which combined STM with fabrics, have been increasingly in demand for impact protective applications due to their tremendous potential. Herein, the characteristics of STM and the effects of fabric reinforcement on STFC impact behaviors are discussed for optimizing their properties and structures. Subsequently, the impact behaviors of STFCs obtained by multiple testing approaches with different impact threats are reviewed systematically. Furthermore, a comprehensive summary of the existing literature on stab, drop-weight, split Hopkinson pressure bar, and ballistic impact protective mechanisms of STFCs is presented. It is found that based on the proper selection of STM types, thorough mechanistic explanations of STFC impact behaviors are instructive and could facilitate the development of wearable protective equipment. The purpose of this critical review is to provide a framework for comparison of the effective impact resistances of STFCs across many applications and to discuss issues for future research.