Vibration Characteristics Of Fluid-structure System Of Clamped Plate With Large Deformation Subjected To Axial Flow

The study of fluid-structure interaction of plate-shell thin-walled structure has broad application prospects in aircraft design,water conservancy and hydropower projects and nuclear reactor fuel assembly.In this thesis,the dynamic response and flow field features of fluid structure interaction system of large deformation clamped elastic thin plates suffered to axial flow are simulated numerically.The structural dynamics equation is discretized by finite element method.The equations for the incompressible two-dimensional viscous fluid(Navier-Stokes equations)are discretized by the finite volume method.A simulation model for the two-dimensional clamped plate in axial flow with two-way fluid-structure interaction is established,which combined mature grid division and strongly nonlinear two-way fluid-structure function in ADINA.It can provide reference for the control and prediction of flow-induced vibration,stability as well as instability of components in various engineering fields.Following are the main contents and results of this study:1.The numerical simulation model for single clamped elastic plate in axial flow is established.The structural dynamics equation and fluid control equation of the clamped plates are introduced,which are discretized with finite element method and finite volume method.With the finite element software ADINA,two-dimensional structure model,axial flow field model,the definition of boundary conditions as well as grid division of thin plate in axial flow are established.Through the numerical simulation,the fluid-structure interaction vibration characteristics and the stability of the large-deflection system of clamped plate with different flow velocities are analyzed.The deflection velocity curve,deflection time-history curve and deflection curve have been obtained respectively.Results show that when the flow velocity is below the critical flow velocity,the plate will be in a stable linear balance;when the flow velocity is over the critical flow velocity,the plate will bend to a new position and the limit cycle vibration will occur near the new position of equilibrium.2.The numerical simulation model for clamped two parallel elastic plates in axial flow is established,The vibration characteristics and stability of the system with different distance-to-length ratio are studied.For fixed distance,the deflection of the parallel plates increases with increasing flow rate;when the flow velocity is below the critical flow velocity of the clamped plates,the parallel plates will move in symmetrical and opposite directions;when the flow velocity is equal to the critical flow velocity,with increasing distance between the two plates,the parallel plates will flutter in new positions;when the flow velocity is over the critical flow velocity,with increasing distance to a certain critical value,the systems will occur anti-phase periodic limit cycle vibration;when the distance increasing to another critical value,the two plates will not affect each other and the system presents flow-induced vibration of the single clamped plate.