Vibration suppression of MR sandwich beams based on fuzzy logic

In this paper, the vibration suppression capabilities of magnetorheological layer in smart beams is investigated. A three-layered beam including magnetorheological elastomer layer sandwiched between two elastic layers is considered. By assuming the properties of magnetorheological layer in the pre-yield region as viscoelastic materials behavior, the governing equations of motion and the corresponding boundary conditions are derived using Hamilton’s principle. Due to field-dependent shear modulus of magnetorheological layer, the stiffness and damping properties of the smart beam can be changed by application of magnetic field. This feature is utilized to suppress the unwanted vibration of the system. The appropriate magnetic field applied over the beam is chosen through a fuzzy controller for improving the transient response. The designed fuzzy controller uses the modal displacement and velocity of the beam as its inputs. The modal parameters of the sandwich beam including the natural frequencies and mode shapes are obtained and validated with existing results. Using the Galerkin method, the temporal equation governing beam’s motion is obtained and then the vibration of smart sandwich beam is investigated using numerical simulations. The results show that the magnetorheological layer along with the designed fuzzy controller can be effectively used to suppress the unwanted vibration of the system. The qualitative and quantitative knowledge resulting from this research is expected to enable the analysis, design and synthesis of smart beams for improving the dynamic performance of smart engineering structures.