Abstract
Dampers are widely applied to protect devices or human body from severe impact or harmful vibration circumstances. Considering that dampers with low velocity exponent have advantages in energy absorption, they have been widely used in antiseismic structures and shock buffering. Non-Newtonian fluid with strong shear-thinning effect is commonly adopted to achieve this goal. To obtain the damping mechanism and find convenient methods to design the nonlinear fluid damper, in this study, a hydraulic damper is filled with 500,000 cSt silicone oil to achieve a low velocity exponent. Drop hammer test is carried out to experimentally obtain its impact and buffering characteristics. Then a coupling model is built to analyze its damping mechanism, which consists of a model of impact system and a computational fluid dynamics (CFD) model. Results from the coupling model can be consistent with the experiment results. Simulation method can help design non-Newtonian fluid dampers more effectively.
Highlights
To promote working precision or avoid impact-vibration damage, dampers are widely used in vehicles [1,2,3], civil buildings [4,5,6], weapons [7,8,9,10,11,12], spacecraft [13, 14], and so on, to absorb energy of vibrations or shocks and suppress the resonance or alleviate the shock acceleration
To enhance the energy absorption capacity, nonNewtonian fluid with shear-thinning effect is commonly adopted as the flow media of the damper
Ruzicka and Derby [15] considered the influence of such velocity-nth power damping on vibration isolation, and it is concluded that under the same excitation amplitude, if the velocity exponent is less than unity, the damping can lead to better displacement transmissibility than traditional linear damping
Summary
To promote working precision or avoid impact-vibration damage, dampers are widely used in vehicles [1,2,3], civil buildings [4,5,6], weapons [7,8,9,10,11,12], spacecraft [13, 14], and so on, to absorb energy of vibrations or shocks and suppress the resonance or alleviate the shock acceleration. Considering the eddy flow throng the damping orifice will enlarge the velocity exponent, to obtain a damper with low velocity exponent, it is necessary to make the flow through the orifice be laminar. A damper filled with high viscosity non-Newtonian fluid, 500,000 cSt silicone oil, is manufactured. Jia et al [17] derived the semianalytic formula for this kind of damper by considering the flow among the ring gap is purely sheared. This flow is of Couette type and the pressure difference cannot be ignored, so the results are untrustful. The supposed model can be used to guide the design of the detailed structure such as the size of the damping orifice, and can supply suggestions in designing the moving parts reasonably
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