Coupled Axisymmetric Finite Element Model of a Magneto-hydraulic Actuator for Active Engine Mounts

摘要

A coupled axisymmetric finite element model is formulated to describe the dynamic performance of a hydraulically amplified Terfenol-D mount actuator. The formulation is based on the weak form representations of Maxwell's equations for electromagnetics and Navier's equation for mechanical systems. Terfenol-D constitutive behavior is modeled using a fully coupled energy averaged model. Fluid pressure is computed from the volumetric deformation of the fluid chamber and coupled back to the structure as tractions on the boundaries encompassing the fluid. Seal friction is modeled using the Lugre friction model. The resulting model equations are coded into COMSOL (a commercial finite element package) which is used for meshing and global assembly of matrices. Results show that the model accurately describes the mechanical and electrical response of the actuator under static and dynamic conditions. At higher frequencies there are some errors in the phase due to the anhysteretic nature of the Terfenol-D constitutive law. A parametric study reveals that the performance of the actuator can be significantly improved by stiffening the fluid chamber components and reducing seal friction.