Impact damping and vibration attenuation in nematic liquid crystal elastomers

Nematic liquid crystal elastomers (LCE). exhibit unique mechanical properties such as large loss behaviour, which makes these materials interesting for damping applications. Here, the authors investigate the effect of anomalous damping in LCEs by comparing impact dissipation in shaped samples with elastic wave transmission and resonance. Nematic liquid crystal elastomers (LCE) exhibit unique mechanical properties, placing them in a category distinct from other viscoelastic systems. One of their most celebrated properties is the 'soft elasticity', leading to a wide plateau of low, nearly-constant stress upon stretching, a characteristically slow stress relaxation, enhanced surface adhesion, and other remarkable effects. The dynamic soft response of LCE to shear deformations leads to the extremely large loss behaviour with the loss factor tan delta approaching unity over a wide temperature and frequency ranges, with clear implications for damping applications. Here we investigate this effect of anomalous damping, optimising the impact and vibration geometries to reach the greatest benefits in vibration isolation and impact damping by accessing internal shear deformation modes. We compare impact energy dissipation in shaped samples and projectiles, with elastic wave transmission and resonance, finding a good correlation between the results of such diverse tests. By comparing with ordinary elastomers used for industrial damping, we demonstrate that the nematic LCE is an exceptional damping material and propose directions that should be explored for further improvements in practical damping applications.

Automated summary

Nematic liquid crystal elastomers (LCE) exhibit unique mechanical properties such as 'soft elasticity', leading to a wide plateau of low stress upon stretching, slow stress relaxation, and enhanced surface adhesion. The extremely large loss behavior and nearly-constant stress make LCE interesting for damping applications, especially in vibration isolation and impact damping. By optimizing impact and vibration geometries, researchers found good correlation between impact energy dissipation in shaped samples and elastic wave transmission, demonstrating the exceptional damping material properties of nematic LCE.