• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.2
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• pp.113-117
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• 2015

This study presents a 3-dimensional flow-structure interaction analysis of subsea risers in water flows. Two structural connectors (flat and circular couplers) were intentionally devised and numerically tested using ANSYS CFX to investigate how these couplers behave under the water flows. In the flow analysis, the water field was constructed with an inlet, outlet, and symmetric boundary conditions. As a result, the responses (drag coefficients and pressure fields) were obtained and the pressure fields were applied for the structural analysis. Finally, the structural responses (displacements and equivalent stresses) of the risers were measured to demonstrate the efficiency of the riser connectors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.251-255
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• 2012

Structural intensity has been mainly utilized to identify vibration energy flow in a vessel. In this paper, the structural intensity of a shuttle tanker subjected to H-moment of the main engine was calculated using a finite element model. From the analysis, it was found that the top-bracing elements, which support the main engine onto the hull structure to prevent the excessive transverse vibration of the main engine, play the role of the dominant path and sink for vibration energy flow from the main engine. Therefore, the structural intensity was controlled by the modification of stiffness and damping characteristics of the top-bracing elements. As a result, it is observed that the transverse vibration level at the center of navigation bridge deck decreased after the control of structural intensity.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.119-126
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• 2004

A continuum-based design sensitivity analysis and topology optimization methods are developed for power flow analysis. Efficient adjoint sensitivity analysis method is employed and further extended to topology optimization problems. Young's moduli of all the finite elements are selected as design variables and parameterized using a bulk material density function. The objective function and constraint are an energy compliance of the system and an allowable volume fraction, respectively. A gradient-based optimization, the modified method of feasible direction, is used to obtain the optimal material layout. Through several numerical examples, we notice that the developed design sensitivity analysis method is very accurate and efficient compared with the finite difference sensitivity. Also, the topology optimization method provides physically meaningful results. The developed is design sensitivity analysis method is very useful to systematically predict the impact on the design variations. Furthermore, the topology optimization method can be utilized in the layout design of structural systems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.88-93
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• 2019

This study concerns the distributions of flow in an air conditioning duct used for a marine and oil drilling ship. From the results of carrying out flow analysis and structural analysis of a ventilation duct applied to a marine structure, the following conclusion could be gained. The pressure tended to increase as the flow velocity at the inlet increased and the pressure at the inlet increased. It was recognized that the pressure decreased due to the influence of a corrugated tube when it entered and exited from the duct. As a result of structural analysis, a higher train was generated at the corrugated tube compared with the duct. In addition, in the case of the internal pressure of 0.7MPa, which was the designed load, it was found that there was almost no influence as it was within 0.1mm.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.9
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• pp.94-99
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• 2019

To evaluate the stability of a pneumatic conveyor system, a flow analysis and structural analysis were performed using the FSI technique. Prototypes were fabricated and verified. As a result of the flow analysis, the maximum pressure applied to the device was calculated to be 0.55 MPa. The structural analysis determined that the maximum stress was 131 MPa and the yield strength of the structure was less than 205 MPa. The safety of the system was confirmed by the fact that no deformation occurred during the manufacturing and operation of the prototype.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.558-567
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• 2020

This study examined the defect characteristics of fuel flow proportioner-mounted structures to analyze the causes of structural defects during aircraft operation. System vibrations and single component vibrations that occur during aircraft operations are usually the cause of structural defects. The fuel flow proportioner causes a defect in the support structure due to the vibration caused by the pressure change caused by the sudden increase in the flow rate. Defects in the support structure of the fuel flow proportioner are not correlated directly with the cracking of the maneuver, and flight time according to aircraft operation analysis is related to the use of A/B. The structural reinforcement configuration was confirmed through static and life analysis of the cracks of the bracket mounted under the fuel flow proportioner for improvement of the defect. An analysis of the reinforcement revealed a minimum structural strength of +0.15. Structural life analysis confirmed that the stress acted on the site under 15Ksi. The fatigue life was confirmed to be more than 7,700 Cycles.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.69-76
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• 2019

In this study, resin flow analysis of resin transfer moulding (RTM) method was performed for mould design of composite structure. The target composite structure was a tank used for fluid storage. Natural c fiber composite was adopted for composite structural design of the fluid storage tank. RTM was adopted for manufacturing of the tank using natural fiber composites. Resin flow analysis was performed to find the proper RTM conditions of the tank. The resin flow analysis was performed using the commercial FEM flow simulation software. After repeated analysis while changing the location of resin inlet and outlet, the proper resin filling time and pattern were found.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.613-616
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• 1997

MDO(Multidisciplinary Design Optimization) methodology is an emerging new technology to solve a complicate structural analysis and design problem with a number of design variables and constraints. In this paper MDO methodology is adopted through the use of computer aided engineering(CAE) system. And this paper treats the structural design problem of RIROB(Reactor Inspection Robot) through the application of MDO methodology. In a MDO methodology application to the structural design of RIBOS, kinetodynamic analysis is done using a simple fluiddynamic analysis model for the warter flow over the sensor support surface instead of difficult fluid dynamic analysis. Simultaneously the structural static analysis is done to obtain the optimum structural condition. The minimum thickness (0.8cm) of the RIROB housing is obtained for the safe design of RIROB. The kinetodynamic analysis of RIROB. The kinetodynamic analysis of RIROB is done using ADAMS and the static structural analysis of RIROB is done using NISA.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.585-590
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• 2003

The distributions of mass flow rate and pressure are major factors to deside the performance of a proton exchange membrane fuel cell (PEMFC). These factors are affected by channel configuration of air plate. In this paper. structural analysis is performed to investigate deformation of porous media. Two kind of models are suggest for flow analyses. Deformed porous media and undeformed porous media are considered for air plate model. The Numerical flow analysis results with deformed porous media and undeformed porous media had some discrepancy in pressure distribution. The pressure and velocity in a working condition are numerically calculated to predict the performance of the air plates. Distributions of the parameters in the PEMFC are analyzed numerically under steady-state conditions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.103-110
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• 1996

In this paper, behaviour of underground structural systems due to excavation and change of groundwater level is analyzed using finite elements. Equilibrium equations based on the effective pressure theory and transient flow equations considering the groundwater level are derived. Integration equations are derived using Galerkin's approximation and time dependent analysis is employed to compute groundwater level change and pore pressures. This computed pore pressures are employed in equilibrium equations and then finally displacements and stresses are computed. The developed program is applied to analyze the behaviour of ground excavation below the groundwater level. The program is also applied to multi-step excavation at the same model. The results show that the displacements of the ground surface are much influenced by the change of the groundwater level. Therefore, it is concluded that the change of the groundwater level should be considered in order to analyze the behaviour of the underground structural systems accurately