Аннотация:Magnetoactive elastomers (or MAE) are composite polymer materials consisting of relatively soft polymeric matrix and ferromagnetic filler particles of different sizes. Such microstructure allows to control various properties of MAEs, for example their shape and stiffness. Hence the applications include tunable mechanical devices as well as cases where elastic subsystem interaction with an external field is important. One such case involves using MAE as a magnetically controlled retinal seal in eye surgery to treat retinal detachment. This work aims to model and study the interaction between MAE seal and a system of permanent magnets.
The model is created using commercially available software COMSOL Multiphysics to solve partial differential equations with finite element method. Various geometric parameters and their influence on the interaction between magnetic and MAE subsystems were considered. Different magnetization orientations in the magnetic subsystem (parallel and anti-parallel) were used. The dependences of both mechanical and magnetic properties of MAE samples on the external magnetic field were studied. MAE samples were represented by either cuboids or spherical segments to simulate the retinal curvature. Two factors were taken into account during modelling of the magnetic properties of subsystems: inhomogeneous magnetization inside the magnets due to demagnetization and the dependence of the MAE’s magnetic permeability on the magnetic field inside the sample (including influence of the sample’s shape).
Dependences of the interaction force acting on the MAE sample on the distance between magnetic and elastomeric subsystems as well as other geometric parameters of the problem were obtained. Pressure distributions on sample’s surfaces were computed. Tangent forces resulting from the sample’s displacement in the direction parallel to the magnetic subsystem were studied. System configurations optimal for practical application in eye surgery were considered. Numerical simulations were supported by real experimental data.