Design of a stiffness adjustable magnetic fluid shock absorber based on optimal stiffness coefficient

With the rapid development of aerospace technology, the vibration problem of the spacecraft flexible structure urgently needs to be solved. Magnetic fluids are a type of multi-functional smart materials, which can be employed in shock absorbers to eliminate these vibrations. Referring to the calculation methods of stiffness coefficients of other passive dampers, the stiffness coefficient formula of magnetic fluid shock absorbers (MFSAs) was derived. Meanwhile, a novel stiffness adjustable magnetic fluid shock absorber (SA-MFSA) was proposed. On the basis of the second-order buoyancy principle, a series of SA-MFSAs were fabricated. The range of stiffness coefficients covered by these SA-MFSAs contains the optimal stiffness coefficient estimated by formulas. The repulsive force measurement and vibration attenuation experiments were conducted on these SA-MFSAs. In the case of small amplitude, the relationship between the repulsive force and the offset distance was linear. The simulation and experiment curves of repulsive forces were in good agreement. The results of vibration attenuation experiments demonstrated that the rod length and the magnetic fluid mass influence the damping efficiency of SA-MFSAs. In addition, these results verified that the SA-MFSA with the optimal stiffness coefficient performed best. Therefore, the stiffness coefficient formula can guide the design of MFSAs.