High Strain Rate Behavior of Liquid Crystal Elastomers

Liquid crystal elastomers are rubbery solids that couple liquid crystalline order and deformation. This coupling leads to properties that are attractive for a number of applications in soft robotics and energy absorption. This paper is motivated by the latter application, and provides a systematic experimental study of a particular class of liquid crystal elastomers -- the isotropic genesis polydomain liquid crystal elastomers -- over a wide range of strain rates. An important aspect of this study is a novel tensile drop-tower that enables tensile strain rates of 100 s$^{-1}$ that are important to application but previously inaccessible. The paper also extends a recently proposed constitutive model to the high strain rate regime, and shows that it can be fit to describe the observed behavior across the spectrum of examined behavior.