Study on the Rocking Motion Suppression of a Structure subjected to Seismic Excitation due to Highly Viscous Liquid of Coaxial Circular Cylinders

2018 ◽  
Vol 2018.93 (0) ◽  
pp. 713
Author(s):  
Masahiro FUJINO ◽  
Atsuhiko SHINTANI ◽  
Tomohiro ITO ◽  
Chihiro NAKAGAWA
Keyword(s):  
Viscous Liquid ◽  
Seismic Excitation ◽  
Circular Cylinders ◽  
Rocking Motion ◽  
Motion Suppression

Mitigation of Rocking and Sliding Motion of a Free-Standing Structure Subjected to Base Excitation Using Coaxial Circular Cylinders Containing Highly Viscous Liquid in Annular Spaces

2019 ◽  
Author(s):  
Atsuhiko Shintani ◽  
Tomohiro Ito ◽  
Chihiro Nakagawa
Keyword(s):  
Rigid Body ◽  
Viscous Liquid ◽  
Analytical Model ◽  
Circular Cylinders ◽  
Base Excitation ◽  
Free Standing ◽  
Seismic Input ◽  
Sliding Motion ◽  
Standing Structure ◽  
Rocking Motion

Abstract In this study, the effectiveness of coaxial circular cylinders containing a highly viscous liquid in annular spaces for reduction of rocking motion of a free-standing structure is investigated both analytically and experimentally. First, an analytical model of coupled rocking and sliding motions of a free-standing structure, including the coaxial circular cylinders, subjected to seismic input was derived. The free-standing structure was modeled as a free-standing rigid body. The cylinders were attached to the bottom of the rigid body as a damping device. We then experimentally derived the friction coefficients, inertia moments, and a damping coefficient in the rotating direction. Furthermore, using these parameters, the effectiveness of this system in suppressing the rocking motion is investigated analytically. The proposed method was determined to be very effective in suppressing the rocking motion of a rigid body subjected to a seismic input by the experiment.

Stability of spiral flow between concentric circular cylinders at low axial Reynolds number

1965 ◽  
Vol 21 (4) ◽  
pp. 635-640 ◽  
Author(s):  
Subhendu K. Datta
Keyword(s):  
Reynolds Number ◽  
Perturbation Theory ◽  
Viscous Liquid ◽  
Axial Flow ◽  
Circular Cylinders ◽  
Rotating Cylinders ◽  
Spiral Flow ◽  
The Stability

The stability of a viscous liquid between two concentric rotating cylinders with an axial flow has been investigated. Attention has been confined to the case when the cylinders are rotating in the same direction, the gap between the cylinders is small and the axial flow is small. A perturbation theory valid in the limit when the axial Reynolds number R → 0 has been developed and corrections have been obtained for Chandrasekhar's earlier results.

Rheometrical flow systems Part 3. Flow between rotating eccentric cylinders

1970 ◽  
Vol 43 (2) ◽  
pp. 257-267 ◽  
Author(s):  
T. N. G. Abbott ◽  
K. Walters
Keyword(s):  
Angular Velocity ◽  
Viscous Liquid ◽  
Dynamic Viscosity ◽  
Circular Cylinders ◽  
Complex Dynamic ◽  
Mathematical Background ◽  
Eccentric Cylinders ◽  
Flow Systems ◽  
On Line

We give further consideration to flow situations which are steady in the sense that ∂/∂t ≡ 0 but for which individual fluid elements are subjected to a small sinusoidal deformation. The particular situation studied involves the flow between eccentric circular cylinders which rotate about their axes with the same angular velocity Ω. The eccentricity is assumed to be small. It is shown that measurements of the force on the inner cylinder can be used to determine the complex dynamic viscosity of an elastico-viscous liquid.The theory provides the necessary mathematical background for the operation of a new commercial rheometer. Consideration is given to the possibility of ‘on-line’ use of such an instrument for control purposes.

Slow Steady Flow of a Viscous Liquid in an Annulus With Uniform Arbitrary Injection and Suction Velocities Along the Walls

1966 ◽  
Vol 33 (3) ◽  
pp. 668-673 ◽  
Author(s):  
S. P. Das
Keyword(s):  
Steady Flow ◽  
Viscous Liquid ◽  
The Other ◽  
Circular Cylinders ◽  
Pressure Distributions

The problem considered here is the slow steady flow of a viscous liquid through the annulus between two coaxial porous circular cylinders which ejects liquid over one wall and sucks in at the other wall, the velocities of injection and suction being uniform but arbitrary. The effects of wall porosity on velocity and pressure distributions are calculated following the method of superposition.

Dynamic Model for Free-Standing Fuel Racks Under Seismic Excitation Considering Planar and Nonslide Rocking Motion

2017 ◽  
Vol 12 (6) ◽  
Author(s):  
Kazuya Sakamoto ◽  
Ryosuke Kan ◽  
Akihiro Takai ◽  
Shigehiko Kaneko
Keyword(s):  
Friction Coefficient ◽  
Dynamic Model ◽  
Friction Force ◽  
Spent Nuclear Fuel ◽  
Inertial Force ◽  
Seismic Excitation ◽  
Free Standing ◽  
Fluid Force ◽  
Translational Movement ◽  
Rocking Motion

A free-standing (FS) rack is a type of a spent nuclear fuel rack, which is just placed on a floor of a pool. For this characteristic, seismic loads can be reduced by fluid force and friction force, but a collision between a rack and another rack or a wall must be avoided. Therefore, it is necessary for designing an FS rack to figure out how it moves under seismic excitation. In this research, a dynamic model of an FS rack is developed considering seismic inertial force, friction force, and fluid force. This model consists of two submodels: a translation model, which simulates planar translational and rotational motion, and a rocking model, which simulates nonslide rocking motion. First, simulations with sinusoidal inertial force were conducted, changing values of a friction coefficient. Next, to validate this dynamic model, a miniature experiment was conducted. Finally, the model is applied to a real-size FS rack and actually observed seismic acceleration. It is found that translational movement of a rack varies depending on the value of friction coefficient in the simulation with sinusoidal and actual acceleration. Also, simulation results are similar to the experimental results in the aspects of translational and rocking motion provided friction coefficient is selected properly. Through this research, the knowledge is acquired that friction force plays a significant role in a motion of FS rack so that estimating and controlling a friction coefficient is important in designing an FS rack.

Benzylamine Tartrate as an Organic Glass Substrate for Carbon Films by Evaporation

1970 ◽  
Vol 28 ◽  
pp. 484-485
Author(s):  
A. C. Faberge
Keyword(s):  
Vapor Pressure ◽  
Viscous Liquid ◽  
Glass Substrate ◽  
Room Temperature ◽  
Carbon Film ◽  
Carbon Films ◽  
Organic Glass ◽  
Spectroscopic Examination ◽  
Polymeric Substrates

Benzylamine tartrate (m.p. 63°C) seems to be a better and more convenient substrate for making carbon films than any of those previously proposed. Using it in the manner described, it is easy consistently to make batches of specimen grids as open as 200 mesh with no broken squares, and without individual handling of the grids. Benzylamine tartrate (hereafter called B.T.) is a viscous liquid when molten, which sets to a glass. Unlike polymeric substrates it does not swell before dissolving; such swelling of the substrate seems to be a principal cause of breakage of carbon film. Mass spectroscopic examination indicates a vapor pressure less than 10−9 Torr at room temperature.

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