• Coupled systems mechanics
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• v.2 no.4
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• pp.389-410
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• 2013

Three-dimensional Lagrangian fluid finite element is applied to seismic response analysis of an oil storage tank with a floating roof. The fluid element utilized in the present analysis is formulated based on the displacement finite element method considering only volumetric elasticity and its element stiffness matrix is derived by using one-point integration method in order to avoid volumetric locking. The method usually adds a rotational penalty stiffness to satisfy the irrotational condition for fluid motion and modifies element mass matrices through the projected mass method to suppress spurious hourglass-mode appeared in compensation for one-point integration. In the fluid element utilized in the present paper, a small hourglass stiffness is employed. The fluid and structure domains for the objective oil storage tank are modeled by eight-node solid elements and four-node shell elements, respectively, and the transient response of the floating roof structure or the free surface are evaluated by implicit direct time integration method. The results of seismic response analyses are compared with those by other method and the validation of the present analysis using three-dimensional Lagrangian fluid finite elements is shown.

• Journal of Ocean Engineering and Technology
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• v.6 no.2
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• pp.46-54
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• 1992

In this paper, behavior of rectangular storage structures under earthquake loadings are investigated. Linear sloshing is assumed in this study. The effect of the wall flexibility is considered. Eulerian and lagrangian approaches are presented. The Eulerian approach is carried out by solving the boundary value problem for the fluid motion. In the lagrangian approach, the fluid as well as the storage structure is modelled by the finite element method. The fluid region is discretized by using fluid elements. The (1 $\times$ 1)-reduced integration is carried out for constructing the stiffness matrices of the fluid elements. Seismic analysis of the coupled system is carried out by the response spectra method. The numerical results show that the fluid forces on the wall obtained by two approaches are in good agreements. By including the effect of the wall flexibility, the forces due to fluid motion can be increased very significantly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.275-282
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• 2007

In this study, a fluid-structure interaction (FSI) analysis system has been developed in order to evaluate the turbine cascade performance with blade structural deformation effect. Relative movement of the rotor with respect to stator is reflected by modeling independent two computational domains. To consider the deformed position of rotor airfoil, dynamic moving grid method is applied. Reynolds-averaged Navier-Stokes equations with one equation Spalart-Allmaras and two-equation SST $k-{\varepsilon}$ turbulence models are solved to predict unsteady fluid dynamic loads. A fully implicit time marching scheme based on the Newmark direct integration method with high artificial damping is used to compute the fluid-structure interaction problem. Cascade performance evaluations for different elastic axis positions are presented and compared each other. It is importantly shown that the predicted aerodynamic performance considering structural deformation effect of blade can show some deviations compared to the data generally computed from rigid blade configurations and the position of elastic axis also tend to give sensitive effect.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.9-18
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• 2016

In this research, the modeling of erosive burning and analysis of effective parameters were carried out for the application of fluid-structure integration analysis. The manufacture, test, and analysis of erosive burning motors were carried out to estimate the erosive burning applying Lenoir & Robillard model considering effective parameters. The erosive burning phenomenon was detected from experimental results. Erosive burning model and its effective parameters were evaluated and analyzed considering existence of aluminum in propellant, relationship among erosive burning coefficients according to characteristic length, effect of grain initial temperature. The erosive burning model was applied to the fluid-structure integration analysis, and the estimated results were close to the experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.764-772
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• 2009

In this study, fluid/structure coupled analyses have been conducted for 3-D stator and rotor configuration. Advanced computational analysis system based on computational fluid dynamics(CFD) and computational structural dynamics(CSD) has been developed in order to investigate fluid/structure responses of general stator-rotor configurations. To solve the fluid/structure coupled problems, fluid domains are modeled using the structural grid system with dynamic moving and local deforming techniques. Reynolds-averaged Navier-Stokes equations with Spalart-Allmaras(S-A) and SST ${\kappa}-{\omega}$ turbulence models are solved for unsteady flow problems. A fully implicit time marching scheme based on the Newmark direct integration method is used for computing the coupled aeroelastic governing equations of the 3-D turbine blades for fluid-structure interaction(FSI) problems. Detailed fluid/structure analysis responses for stator-rotor interaction flow conditions are presented to show the physical performance and flow characteristics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.563-569
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• 2008

In this study, fluid/structure coupled analyses have been conducted f3r 3-D stator and rotor configuration. Advanced computational analysis system based on computational fluid dynamics (CFD) and computational structural dynamics (CSD) has been developed in order to investigate fluid/structure responses of general stator-rotor configurations. To solve the fluid/structure coupled problems, fluid domains are modeled using the structural grid system with dynamic moving and local deforming techniques. Reynolds-averaged Navier-Stokes equations with Spalart-Allmaras (S-A) and SST ${\kappa}-{\omega}$ turbulence models are solved for unsteady flow problems. A fully implicit time marching scheme based on the Newmark direct integration method is used for computing the coupled aeroelastic governing equations of the 3-D turbine blades for fluid-structure interaction (FSI) problems. Detailed fluid/structure analysis responses for stator-rotor interaction flow conditions are presented to show the physical performance and flow characteristics.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.333-346
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• 2014

If we want to analyze the motion of a body in fluid, we should use rigid-body dynamics and fluid dynamics together. Even if the rigid-body and fluid dynamics are each self-consistent, there arises the problem of self-similar structure in the equation of motion when the two dynamics are coupled with each other. When the added mass is greater than the mass of a body, the calculated motion is divergent because of its self-similar structure. This study showed that the above problem is an inherent problem. This problem of self-similar structure may arise in the equation of motion in which the fluid dynamic forces are treated as external forces on the right hand side of the equation. A reconfiguration technique for the equation of motion using pseudo-added-mass was proposed to resolve the self-similar structure problem; specifically for the case when the fluid force is expressed by integration of the fluid pressure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.427-434
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• 2000

This paper presents a computer program for a 2-D fluid-structure-soil interaction analysis. With this computer program the fluid can be modeled by a spurious free 4-node displacement-based fluid element which uses rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and near field soil are discretized by the standard finite elements while the unbounded far field soil are discretized by the standard finite elements while the unbounded far field soil is represented by the frequency dependent dynamic infinite elements. Sine this method models directly the fluid-structure-soil system it can be applied to the dynamci analysis of 2-D liquid storage structure with complex geometry. For the purpose of verification dynamic analyses for tanks on a rigid foundation and on compliant embankment are carried out. Comparison of the present results with those by ANSYS program shows good agreement.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.289-296
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• 2000

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.132-137
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• 2001

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.