Modeling And Dynamic Analysis Of Magnetorheological Fluid Sandwich Beam

The Magnetorheological fluid(MRF) sandwich structure is one of the composite structures which combine the MRF to other infrastructures such as beams, plates, thin shells and so on. With the influence of an external magnetic field, the properties of the MRF can be changed from the liquid state to the solid one rapidly, and the change can be revisable and controllable. Therefore, the stiffness and damping of the MRF sandwich structure can be controlled through the control of the applied magnetic field. Based on the above, it can be found that the MRF sandwich structure has great potential applications in different engineering areas, such as soundproof room(mechanical engineering), air refueling hose(aerospace engineering), prostheses(Biomechanical engineering) and so on. For the research of the MRF sandwich structure, the investigation of MRF sandwich beams is one of the fundamental issues. Therefore, this dissertation will be mainly focused on the modeling and dynamic analysis of the MRF sandwich beam.The investigation of the shear constitutive relationship of MRF will be presented in this dissertation. The shear stress-strain relationship will be established based on the complex shear modulus to represent the shear stress-strain relationship. The differential equations of motion of the MRF sandwich beams will be proposed based on the Extended-Harmiton’s principle. Finally, the equation of motion of the MRF sandwich beams in the FEM form, which includes the hollow, whole and partial treated MRF sandwich beams, will be established and then the analysis of vibration characteristics will be presented on the basis of the established model.The validity of the established FE model will be verified through the experimental study. The MRF sandwich beams with the Clamped-Free boundary condition will be investigated based on the experimental setup. Good agreement can be found through comparison of the analytical and experimental results. The cantilever MRF sandwich beam’s power spectral density of acceleration response with the random excitation under different magnetic field will be analyzed considering the damping effect of the elastic layer. And then the analysis will be extended to the MRF sandwich beams with different boundary conditions, treated methodologies and applied magnetic fields. The results will be verified through the comparison with the investigation presented in available literatures.