On the Improvement of Thermal Protection for Temperature-Responsive Protective Clothing Incorporated with Shape Memory Alloy.

Jiazhen He,Nini Ma,Lijun Wang,Yehu Lu

doi:10.3390/ma11101932

Abstract

This study explored the application of shape memory alloy (SMA) springs in a multilayer protective fabric assembly for intelligent insulation that responded to thermal environment changes. Once the SMA spring was actuated, clothing layers were separated, creating an adjustable air gap between the adjacent fabric layers. The impacts of six different SMA arrangement modes and two different spring sizes on thermal protection against either a radiant heat exposure (12 kW/m2) or a hot surface exposure (400 °C) were investigated. The findings showed that the incorporation of SMA springs into the fabric assembly improved the thermal protection, but the extent to which the springs provided thermal protection was dependent on the arrangement mode and spring size. The effectiveness of reinforcing the protective performance using SMA springs depended on the ability of clothing layers to expand an air layer. The regression models were established to quantitatively assess the relationship between the air gap formed by SMA spring and the thermal protective performance of clothing. This study demonstrated the potential of SMA spring as a suitable material for the development of intelligent garments to provide additional thermal protection and thus reduce the number of clothing layers for transitional thermal protective clothing.

Highlights

Thermal hazards are common dangers faced by firefighters, industrial workers in the metallurgical and energy industry, military personnel, and race car drivers
Temperature profiles obtained for the No-cut shape memory alloy (SMA) springs were presented first as examples of how heat transfers through the fabric assembly under the Radiant heat exposures (RHE) condition
Resulted in higher temperatures on the external and internal surfaces of the thermal liner in comparison to the fabric assemblies with any SMA arrangement incorporated within them. This was because the SMA springs, with an actuation temperature 45 ◦ C, was expanded to form a steady air gap between the moisture barrier and the thermal liner when the fabric assembly was exposed to thermal hazards

Summary

Introduction

Thermal hazards are common dangers faced by firefighters, industrial workers in the metallurgical and energy industry, military personnel, and race car drivers. Intense heat transfer from the thermal environment to human skin may result in severe skin burn injuries. Prevention of skin burn injuries associated with exposure to thermal hazards has long been identified as the primary function of thermal protective clothing (TPC) [1]. TPC with excellent thermal protective performance is essential to protect the body from external heat exposure hazards. To improve the thermal protective performance of clothing, new types of textile fibers need to be developed, as they are the basic raw materials needed to manufacture clothing. Adding layers or thickness to fabrics is an effective way to improve the thermal insulation of protective clothing [3,4], thereby decreasing the heat transfer through thermal environments. Multilayered and thick fabrics can store a lot of thermal energy during

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