Numerical investigation of subtle feature of geometry effects on magneto-active elastomer cylindrical actuators

Magneto-active elastomers (MAEs) are smart composite materials capable of undergoing large deformation when subjected to external magnetic fields, making them attractive for soft actuation and adaptive structures. In this study, a nonlinear finite element framework is developed to investigate the magnetically induced deformation behaviour of cylindrical MAE actuators subjected to radial magnetic loading. The magneto-mechanical response of the material is described using a continuum magneto-elastic constitutive model implemented through a user-defined material subroutine (VUMAT) within the ABAQUS/Explicit environment. The developed numerical model is used to examine the influence of the coupling parameters $\alpha$ and $\beta$ governing the magneto-mechanical interaction on the deformation and stress distribution of the actuator. Parametric studies reveal that increasing the magnetic coupling parameters significantly enhances circumferential deformation while producing localized stress concentrations near the inner boundary of the cylindrical structure. The results further demonstrate a nonlinear interaction between the coupling parameters that strongly influences actuator performance. The findings provide insight into the role of constitutive and geometric parameters in magnetically driven soft actuators and offer useful guidelines for the design and optimization of MAE-based cylindrical actuation systems.