| Double-rod pore-type viscous fluid dampers(VFD), mainly composed of viscous fluid, pistons, etc., are widely used in bridges and tall buildings for its simplicity, excellent sealing performance and less auxiliary stiffness provided.A new kind of VFD filled with silt and oil is proposed in this paper. The addition of silt can increase the viscosity of viscous media, which make the damper able to provide bigger force as well as the feature of speed-related sticky energy dissipation and displacement-related hysteretic energy dissipation. What’s more, the interaction between oil and silt is relatively much larger that can lighten oil spilling. Based on theoretical analysis, finite element simulation analysis, damper performance test, hysteretic performance fitting, etc., the oil-silt viscous fluid damper is researched in many aspects.Firstly, the basic theory of viscous dampers type and energy dissipation mechanism are systematic exposited according to available researches. Then a new kind of damper is designed with two kinds of damping holes in the piston. And its performance is tested in Chongqing University large shaking table laboratory. For subsequent research, a fitting formula is given for simulate the damper. Then, through CFD software Fluent, 3D simulation of the damper is done for having a better understanding of those facts’ influence rules that affect the damper’s performance. Lastly, structural model with and without the dampers are built respectively for dynamic analysis, and the dampers’ energy dissipation effect is also researched.Through those steps mentioned above, some conclusions can be obtained as follows:Adding silt can increase the damping force obviously. The mixture of silt and simethicone as viscous medium has good energy dissipation performance as well as large damping force. However, the proportion of silt should be appropriate to make sure the viscous is flowable.The addition of silt make the damping force contains the displacement-related hysteretic force and the speed-related viscous damping force, which make the energy disspation model from speed-related to mainly displacement-related under lager deformation and mainly speed-related under samll deformation.3D Fluent simulation shows if small displacement condition and pinching effect can be ignored, the energy dissipation model of this new viscous damper is much more close to linear model, and the relationship between the damping force and speed appears to be approximately proportional. What’s more, the damping force produced by the pressure difference on both sides of the piston is far greater than the drag force in the damping holes, which means the viscous is the main fact that dissipate earthquake energy.Time history analysis shows that the new kind of dampers proposed can help the structure absorb shock effectively compared with the structure without dampers. It is easy to see that the maximum displacement of the top floor with dampers all decreased.After a series researches some innovation can be conclude as follows,Silt is put forward to the traditional viscous damper and its performance is verified to be good through both experiment and simulation. Tests also shows different energy mechanism are complxed in the damper, and this hybrid energy dissipation method is the new idea of damper designing.It is very difficult to analyze the dynamic characteristics of oil-silt since their interaction is so complicate. By means of simplification about the compounds, the damper is simulated by CFD software Fluent and good simulation results can be obtained.Based on Rosenbrock integration method, time history analysis of 2D frame structure with and without the new damper are proposed by MATLAB procedure. The results show that the damper’s energy dissipation effect is obvious and the Rosenbrock integration method is rapid and accurate. |
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