Homogeneous and hierarchical composite soft dielectric elastomer actuators: constitutive modelling, homogenization and instabilities
Prof Massimiliano Gei (Cardiff University)
Thursday 23rd March, 2017 14:00-15:00 Maths 515
(Lunch with the speaker will be at One A The Square, leaving from the school front foyer at 12.45.)
Predictive models for Dielectric Elastomer Actuators require the nonlinear solid mechanics theory of soft dielectrics. This is certainly true for homogeneous systems, but also for devices made of composite materials, where the insertion of stiff conductive particles in the soft matrix may help to improve the overall actuation performance. In the talk, I present a theoretical framework to investigate a wide range of instabilities in both homogeneous and composite-manufactured actuators: pull-in/electromechanical instability, buckling-like modes and band-localization failure, that can be analysed taking into account all the geometric and electromechanical properties of the device such as i) nonlinearities associated with large strains and the employed material model; ii) initial prestretch applied to the system; iii) dependency of the permittivity on the deformation (electrostriction). In the second part, I will focus on the performance of layered composites highlighting the effect of the induced dielectric anisotropy on the optimal configurations to maximise actuation stretches.