Performance comparison between an MRF damper and an MRE isolator incorporated with a building structure

As an important member of smart materials, magnetorheological elastomers (MREs) exhibit characteristics that their modulus can be controlled by an external magnetic field. Based on these experimental results, a viscoelastic solid model with four parameters was proposed to predict the performance of MRE. A building model, three stories high, was constructed using MATLAB SIMULINK to evaluate the performance of an MRE device in structural control. In addition, the performance of an MRF damper and an MRE device in structural control, where the resultant peak force was selected as a criterion in the evaluation process, was compared and discussed. Two controllers, passive on and passive off control strategy were used to compare the response of structure. The effectiveness of an MRE bearing in structural control was well justified. Introduction MRE material consists of suspensions of polarised particles in a non-magnetic solid or gel-like matrix. These polarised particles can be arranged in chains in polymer media such as silicon rubber and natural rubber [1-3]. When a magnetic field is applied MRE materials can perform a controllable shear modulus with the magnetic field. Although many mathematical models for applications of MR materials [4-6] have been developed, they have not often been used to express the character of MRE materials. In this study, a four-parameter phenomenological model was proposed to investigate different approaches to modeling MRE materials based on experimental results. Then, a comparison between an MRF damper and MRE device in structural control was outlined. The resultant peak force was selected as a criterion in this evaluation process. The structural response including displacement and acceleration, were evaluated when an MRF damper and an MRE device were incorporated into a three storied building. Two controllers, passive on and passive off control strategy were used in comparison to evaluate the performances of MRF damper and an MRE isolator in structural control. Study of An MRF Damper According to Dyke et al [7], an MR fluid damper is one of a number of effective devices which are used to control the structural response in displacement and acceleration. This damper can generate various control forces due to changes of the external magnetic flux density. These sorts of control forces play very important roles in controlling structures. A Bouc-wen phenomenological model was developed to simulate the characteristics of MR effects for MR fluid dampers [7]. A typical Bouc-wen model with a simple mechanical idealisation is shown in Fig.1. The related equations governing the control force f predicted by this model are given by 1 1 0 ( ) d f c y k x x    , 1 1 ( ) ( ) n n d d d z x y z z x y z A x y           , (1)