Panel Deployment Using Ultrafast SMA Latches

Abstract

Advanced material systems are continuously being sought for energy absorption during impact, but these materials still tend to be heavy and expensive. An alternative approach is to actively increase the crush distance using deployable panels. Depending on the closing speed of "bullet" and "target" objects and the detection range of the pre-impact sensor, for a deployable panel to be effective in energy management, as little as 30-50 ms may be available for releasing, deploying, and in some applications stopping the panel. This paper presents the development of a stored energy panel deployment approach that meets this challenging time regime through a combination of traditional and smart materials technologies selected via a thorough downselection process. In the chosen approach, a light, compact, and inexpensive ultra-fast SMA latch releases energy from traditional compressed springs to deploy a panel which is stopped with integrated shock absorbers. A full-scale integrated prototype was designed, built and experimentally characterized for two bounding cases: 30 ms deploy demanding high force/power and a 50 ms deploy with associated lower force/power requirements. In both cases, the proof-of-concept shows promising performance metrics well within these two specified target deployment times. Given this, when coupled with advanced sensing technology, this system provides a promising alternative mechanism useful for military applications such as projectile interception on vehicles, ships and combat quarters as well as civilian applications such as commercial vehicles and structural terrorist threats.