Dynamic Characteristics Of A Sandwich Beam With Magnetorheological Hexagonal Honeycomb Structured Core

Magnetorheological elastomers(MREs)are a class of so-called smart materials that change their viscoelastic properties in response to an external stimulus.Magnetorheological(MR)materials can be in the form of liquids,gels,or solids such as elastomers.When exposed to an external magnetic field,the mechanical characteristics of MR materials change.MREs are intriguing options for structural system active stiffness and vibration control.Sandwich composite structures are widely used in applications that call for high stiffness-toweight ratios,high strength-to-weight ratios,and high energy absorption capacities.The most prevalent uses are needed in the industries of aviation,automobiles,and ships.Two very thin skins are connected to a lightweight core,creating a bond.The mechanical properties of sandwich composite structures are greatly influenced by the core material and the structure’s architecture.In terms of stiffness,mechanical stability,and energy absorption,typical honeycomb cellular cores beat random porous foams.Studies involving MRE are interested in this form of construction because it permits the geometric layout of the cells to modify the rigidity of the sandwich panel.This research is distinguished by its usage of hexagonal honeycomb core sandwich panels loaded with MRE.This study’s major objective is to demonstrate the structural viability of a hexagonal honeycomb cored sandwich panel reinforced with MRE.The purpose of this work was to advance our understanding of the mechanical and dynamic features of sandwich beam structures with a hexagonal honeycomb core made of a different material and filled with a different ratio of MRE.The purpose of this study was to elucidate how the dynamic properties of various proposed structures change when subjected to magnetic fields at various places.MREs based on silicon elastomer and iron particles were manufactured and filled in the honeycomb cores of Resin8000 and Nylon 3D printed in varied ratios of 25% and 50%.By sandwiching a honeycomb core-filled MRE between two thin layers of aluminum,an MRE sandwich beam was created.An experimental test rig was constructed to conduct sine sweep(forced vibration)testing on the proposed structures to determine their frequency and amplitude responses with and without magnetic fields applied at various locations on the structures.The experiment results indicated that when the applied magnetic field increased,the first natural frequency of all proposed structures decreased.The change was greater when the magnetic field was applied to the structure’s free end than when it was applied to the structure’s center.When the amplitude response was examined,the identical reaction was obtained.The amplitude of all structures investigated decreased as the applied magnetic field increased.Second,structures with a Nylon honeycomb core and(50/50)% MRE exhibited the greatest change in frequency and amplitude when a magnetic field was applied to the free end of the structure.The second stage of the study involved the construction of an experimental test rig for conducting classic shock(free vibration)testing on the proposed structures in order to assess their damping and stiffness responses with and without magnetic fields applied at various points on the structures.The damping ratio was determined using the logarithmic decrement approach,and the damping coefficient and stiffness of all structures were determined analytically for various applied magnetic fields at various places.The experiment results suggested that the damping ratio and damping coefficient values increased as the applied magnetic field increased.When the magnetic field was applied to the structure’s center,the change was greater than when it was applied to the structure’s free end.When the stiffness response was investigated,it was found to be the inverse of the damping response.All structures investigated decreased stiffness as the applied magnetic field increased,and the difference was more apparent when magnets were put at the structures’ free ends.The construction composed of a nylon honeycomb core and(50/50)% MRE displayed the highest change in damping and stiffness characteristics as it was discovered for frequency and amplitude response.Subsequently,ANSYS EDT numerical model software was used to create the finite element models,which were used to calculate the magnitude and influence area of the magnetic force generated by magnets on the sandwich beam structure when they were placed at the free end and center of the structure,respectively.The determined force magnitude was then used to run a modal response simulation of the structure in ANSYS Workbench using the results.With an increase in magnetic field strength,it was discovered that the first natural frequencies of the sandwich beam structures under consideration reduced,and that the variation was significant when magnets were positioned at the free ends of the structures.Second,the findings of both the experiments and the simulations revealed a strong correlation between them.