The fluid-structure yoke phenomena addition the trouble in planing a safe underwater construction, particularly for those constructions subject to impact tonss. Although legion experimental researches on fluid-structure yoke have focused on quiver of stiff organic structure under H2O around the balance place, small old work considers the elastic or big fictile distortion of constructions driven by fluid. In the present paper, an experiment platform for look intoing on the dynamic response and verify the simulation algorithm for fluid-structure yoke job, with both big supplanting and big distortion, was set up. Numeric simulation involved hit procedure of deformable constructions driven by fluid is engaged, and several interface matching parametric quantities were discussed. And the distributions of force per unit area and flow speed in fluid sphere, every bit good as the strain distribution in construction sphere, were besides obtained. The comparing between numerical simulation and experimental measuring are acceptable for technology jobs.
Phenomenon of fluid-structure yoke has been widely existed in whole-vertical or parts fabricating procedure. Not merely consequence on the doing preciseness but besides driving safety, particularly would bring on the losingss which involved staff and belongings. To day of the month, researches of fluid-structure yoke which generated from two different Fieldss of solid mechanics and fluid mechanics are still lack, therefore scientific account and steering go more important for analyzing above jobs. And most of researches on fluid-structure yoke focal point on the distortion and supplanting due to their essentialness and practical significance[ 1,2 ].Coupling interface normally divided into two groups: One is merely generated from interface between fluid and solid sphere, would non act upon on constituent equation such as pneumatic.And the other job is that parts or all from fluid zone and solid zone are overlapped such as infiltration.This paper mainlyaiming at the first sort to research[ 3 ].
In this paper, simulation analysis of Fluid-driven deformable Structure in crashing procedure is chiefly discussed by utilizing Fluent and LS-DYNA. In order to heighten the computation truth of each physical field, Simulation method and informations transmittal manner are involved. Research of fluid-structure matching by and large depend on air current tunnel trial, nevertheless, for provide tradeoff between cost and truth, new experiment platform which can be used as look intoing on rotational impact procedure of shell with unstable driven is developed. The high cost of the experiment, physical testing and besides the development of new finite component codifications make design proof by agencies of numerical methods really attractive.
Work feature of fluid-structure yoke shows matching consequence which take topographic point from the interface between two stages, control equations of construction and fluid sphere are established through some conditions such as displacement coordination, equilibrium and energy preservation[ 4 ] .
Fluid sphere equation combined with construction sphere equation, and besides should run into undermentioned equations: mass preservation equation in fluid sphere ( Eq.1 ) , momentum preservation equation in fluid sphere ( Eq.2 ) , elastic construction kineticss equation ( Eq.3 ) .
In the equations, represents operator, ,the fluid speed,is unstable denseness, t represents clip,being force per unit area in fluid sphere,is viscosity coefficient in fluid sphere,, the volume force in fluid sphere,is construction organic structure supplanting,is construction organic structure denseness,is muffling coefficient,is emphasis tensor, andis volume force of construction organic structure.
There are some matching relationships between each parametric quantity in the constituted procedure of uniting fluid sphere and construction domain constituent equations. And informations transportation besides follow the interface status of matching[ 5 ].
Though comparative analysis of parallel yoke and sequence yoke, find that execution for parallel algorithm is non realized easy in practical application due to requirement for a whole convergent thinkers with fluid and construction. By contrast, sequence matching algorithm merely necessitate to take the suited measure size, it could cipher more existent simulation consequences. From above all, sequence matching algorithm is applied in this paper to research the quiver procedure of fluid-driven deformable Structure under H2O. Then, the job is divided into two groups: rotary motion procedure of solid boundary which is calculated by the Fluent, rotary motion impact procedure with LS-DYNA. The computation consequences from user-defined plans are loaded on LS-DYNA which are served as initial status in hit procedure.
Most of the research on fluid-structure yoke experiment has focused on quiver or stiff organic structure supplanting at the balance place. Relatively small attending has been given to their elastic distortion and construction big supplanting, particularly the distortion gesture of unstable driven construction[ 6,7 ]. Therefore, a comparative simple experiment equipment on construction and rule is designed for researching matching phenomenon of construction big supplanting and distortion.
3.1 Experiments Platform
Fig.1. Measurement rule of experimental platform[ 8 ]
Fig.2. Conventional diagram of construction rotary motion driven by fluids[ 8 ]
Fig.3. Full position of fluid-structure matching experimental device[ 8 ]
1-Storage tanki?›2- Supporti?›3-PVC Pipei?›4- Target flowmeteri?›5- valvei?›6- Water channeli?›7- Rotation shafti?›8-Bearingi?›9- Bearing blocki?›10- Bafflei?›11- Strain gaugei?›12-Collision picker leveri?›13- Angular supplanting sensori?›14- Flexible couplingi?›15- Dynamic strain indicatori?›16- Signal aggregation dealing and analysis apparatusi?›
In the equipment, fluid in the upper H2O storage armored combat vehicle flows into gulch as shown in fig.2, and drives the shell to revolve. Inlet perpendicular to the initial plane of home base ( fig.2 ) .Plate could revolve automatically inhigh dam dip pool, and impacted on stiff trave rod at the 40 grade where the largest distortion is appeared. For the adequate little rotational inactiveness, lightweight stuff such as Nylon is used to fabricate shaft. And a force per unit area device fitted on H2O storage armored combat vehicle is designed to bring forth different sorts of flow speed.
3.2 Test consequence
Displacement-Time history of shell on the four sorts of driven-flow velocity is received by utilizing angular supplanting detector, as shown in fig.3.Four curves from figures have the similar forms show that impact procedure which driven-structure under unstable force impact on the picker lever after revolving 40 grades. Meanwhile, more high velocity the fluid has, larger angle the shell has, because of the great kinetic energy which is induced by recess fluid speed.
Fig.4.Time histroy of the home base rotating
In order to analysis the home base mechanical belongingss in the interaction procedure with fluid, Torque -Time history under different driven flow speed is obtained as shown in fig.4.
Stress of installing place is measured by using strain gage which is fitted on the home base, the enumeration is shown in fig.5. Number 1 and 3 are installed on the back face of home base, figure 2 is installed on the home base forepart.
Fig.5. Adhesion positios of strain gages
Maximum emphasis of mensurating points in the rotating impact procedure as shown in table 1.
From table 1, it is clearly shown that maximal emphasis of each mensurating points become greater which there is higher flow speed.And the maximal emphasis on the impact place of home base and picker lever is greater than the remainder of emphasis.
In the present research of bidirectional transeunt fluid-structure yoke, most of survey objects merely exist little distortion and supplanting in the construction sphere. Though Workbench could be used for work outing fluid-structure yoke jobs, it is non suited for prosecuting in dynamic impact jobs. Therefore, a simulation method which is combined FlUENT and LS-DYNA is proposed to look into the rotational hit procedure of driven-structure, and informations is transmitted by Matlab. Collision procedure could be divided into two parts: one is the solid boundary rotational procedure, the other is the impacting procedure, where force per unit area of fluid imposed on home base is abstracted by Matlab from Fluent and introduced into LS-DYNA.
Fluid sphere theoretical account is defined by the existent state of affairs in experimental status, specific size is shown in table 2.The size and stuff of hit home base is the same as existent status. Length is 165mm, breadth is 90mm, tallness is 3mm, stuff belongingss is shown in table 3. The diameter of picker lever is 10mm, stuff is 45 # steel.
Pressure and flow speed distribution of home base is obtained though Fluent simulation. The entire clip from revolving to discontinue is 0.054si??Pressure distributions of 0.014s and 0.054s are severally obtained, as shown in fig.6 and fig.7.
Fig.6 Pressure distribution in fluid sphere Fig.7 Pressure distribution in fluid sphere
at 0.014sat 0.054s
Upstream face is ever under the barotropic province because of the impacting from H2O flow. It is besides clearly that force per unit area difference between two sides of home base is observed. Boundary status of unstable field and force per unit area distribution would been changed due to the home base place. Flow speed in fluid sphere at 0.014s and 0.054s is severally obtained, as shown in fig.8 and fig.9.
Fig.8 Diagram of speed vector in fluid sphere Fig.9 Diagram of speed vector in fluidat 0.014ssphere at 0.054s
From the flow speed distribution it is besides possible to detect the trajectory procedure of home base in solid sphere. When the home base is driven by impacting of flow which the flow midplane at entry of round tubing as centre, and speed lessening s from home base centre to around. The angle between flow and plate surface is declined bit by bit while at certain angle of home base. Maximum flow speed ever at the round tubing recess midplane. Fluid-structure yoke parametric quantities is force per unit area on the home base which is acted by flow, besides is the input parametric quantities of impact and hit procedure with LS-DYNA. Then, stress distribution of hit minute of home base and shaft could be obtained.
For the research of revolving hit procedure of driven-structure distortion, it is chiefly see that the place and the value of maximal emphasis. While finite element theoretical account of hit minute is shown in fig.10, stress distribution at the impacting minute is besides in fig.11.
Fig.10Finite component theoretical account at hit minute
Fig.11 ( a ) Stress distribution at hit minute and ( B ) stress-time history at hit point
Though the simulation consequence, it is evidently to demo that maximal emphasis generated at the hit contact point ( that is element 412 ) . Calculated the clip of impacting procedure between home base and picker lever and obtained the hit minute is 0.0022s. Finally, Stress distribution in the procedure of impacting contact point is shown in fig.11, and maximal emphasis is 20.5e6Pa.
4.3 Compared with experiment consequence
While the flow speed is 5.9m/s, strain original clip history at the experiment hit point and stress clip history of simulation hit point are obtained as shown in table 4. Maximal emphasis of sample hit point from ciphering is 15.48e6Pa, and maximal emphasis from imitating is 20.5e6Pa. Attendant minute s of experiment home base and simulation home base are severally 0.21and 0.4, it is clearly to get that the simulation consequences are close to experiment.
In this paper, a new experiment platform developed by our lab for simulation and experiment research on fluid-structure yoke jobs is introduced. This device could be used to mensurate the kineticss response of the traveling submerged construction under impact burden, such as the transient revolving angle, impact strain, recess fluid velocity, and so on. Compared the simulation consequences from LS-DYNA and FlUENT with the measuring consequences, a simulation algorithm suited for technology application is provide, and some cardinal matching control parametric quantities were investigated.
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