Modeling And Research Of Magnetorheological Fluid Sandwich Beam Considering Shear Deformation

The physical properties of the Magnetorheological fluid?MRF?can be changed with the change of magnetic field intensity.The Magnetorheological fluid?MRF?sandwich beams can been got when the MRF is combined to beams.The stiffness and damping of the MRF sandwich beams can be controlled through the control of the applied magnetic field,because of the physical properties of the MRF Change with the change of magnetic field intensity.This controllable property of MRF sandwich beam structure makes it very important in the field of mechanical engineering such as vibration reduction,polishing and noise reduction.Therefore,this paper will mainly study the natural frequency,loss factor and response under external excitation of MRF sandwich beam structure,the main contents include the following aspects.1.This dissertation will summarize the basic components of MRF,the preparation methods of high performance MRF,the shear constitutive relationship and the application of the MRF.This dissertation will also summarize the research status and application of magnetorheological fluid sandwich beams.2.According to the elementary beam theory^[1]and the knowledge of finite element,the effect of shear deformation is considered in the modeling of MRF sandwich beams^[2].Then,the energy analysis of MRF sandwich beam considering shear deformation is carried out,and the dynamic differential equation of the structure is established by using Hamilton principle.Based on that,the natural frequencies and loss factors of MRF sandwich beams are calculated and analyzed.Finally,the author will prepare MRF sandwich beams and build experimental platforms to verify the correctness of the model established in this paper by the vibration experiments of MRF sandwich beams.3.The SQP optimization method is used to optimize the complex shear modulus of magnetorheological fluids,which improves the accuracy of the calculated values of the vibration characteristics of MRF sandwich beams.The state space equation of MRF sandwich beam considering shear deformation and finished the optimization is established,and the power spectral density curve of acceleration response of MRF sandwich cantilever beam under stationary random excitation is calculated.In order to study the influence of thickness on the vibration characteristics of MRF sandwich beams,the influence of beams thickness on the first peak value of acceleration power spectral density curve and the natural frequency of MRF sandwich beam is analyzed.