Abstract
Magnetorheological elastomer (MRE) is a type of magnetic soft material consisting of ferromagnetic particles embedded in a polymeric matrix. MRE-based devices have characteristics of adjustable stiffness and damping properties, and highly nonlinear and hysteretic force–displacement responses that are dependent on external excitations and applied magnetic fields. To effectively implement the devices in mitigating the hazard vibrations of structures, numerically traceable and computationally efficient models should be firstly developed to accurately present the unique behaviors of MREs, including the typical Payne effect and strain stiffening of rubbers etc. In this study, the up-to-date phenomenological models for describing hysteresis response of MRE devices are experimentally investigated. A prototype of MRE isolator is dynamically tested using a shaking table in the laboratory, and the tests are conducted based on displacement control using harmonic inputs with various loading frequencies, amplitudes and applied current levels. Then, the test results are used to identify the parameters of different phenomenological models for model performance evaluation. The procedure of model identification can be considered as solving a global minimization optimization problem, in which the fitness function is the root mean square error between the experimental data and the model prediction. The genetic algorithm (GA) is employed to solve the optimization problem for optimal model parameters due to its advantages of easy coding and fast convergence. Finally, several evaluation indices are adopted to compare the performances of different models, and the result shows that the improved LuGre friction model outperforms other models and has optimal accuracy in predicting the hysteresis response of the MRE device.
Highlights
As a novel type of smart materials, magnetorheological elastomer (MRE) has received remarkable recognition in engineering applications
It is clearly observed that the device displays hysteretic loops in the shear force–displacement/velocity responses, which has the characteristic of strain stiffening under the influence of external current, as illustrated in previous studies
Apart from the impedance from the polymeric matrix, the ferromagnetic particles are constrained by the interaction forces from neighboring ferromagnetic particles due to the magnetic field
Summary
As a novel type of smart materials, magnetorheological elastomer (MRE) has received remarkable recognition in engineering applications. When MRE devices are employed for structural vibration suppression, the corresponding control systems should be developed to allow semi-active control of the devices for protecting the structures against external hazard vibrations These devices have promising prospects in sufficient vibration mitigation, the main challenge for their engineering application is to model their highly nonlinear and hysteretic stress–strain/force–displacement behavior. The number of model parameters should be as few as possible so that the corresponding real-time controller is easy to implement in practice To meet this requirement, different researchers have proposed various modeling methods for the dynamic behaviors of the MRE materials and devices, which are generally categorized as parametric and nonparametric modeling.
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