• 한국소음진동공학회논문집
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• 제17권4호
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• pp.356-362
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• 2007

Magnetostrictive materials have been used for linear actuators due to its large strain, large force output with moderate frequency band in the presence of magnetic field. However their performance analysis is difficult because of nonlinear material behaviors in terms of coupled strain-magnetic field dependence, nonlinear permeability, pre-stress dependence and hysteresis. This paper presents a finite element analysis technique for magnetostrictive linear actuator. To deal with coupled problems and nonlinear behaviors, a simple finite element approach is proposed, which is based on separate magnetic field calculation and displacement simulation. The finite element formulation and an in-house program development are illustrated, and a simulation model is made for a magnetostrictive linear actuator. The fabrication and performance test of the linear actuator are explained, and the performance comparison with simulation result is shown. Since this approach is simple, it can be applied for analyzing magnetostrictive underwater projectors and ultrasonic transducers.

• 한국지반공학회논문집
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• 제22권10호
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• pp.5-20
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• 2006

본 논문에서는 지하수위 하에서 터널이 시공되는 조건을 대상으로 응력-간극수압 연계 유한요소해석 수행시 모델링 측면에서 중요하게 다뤄져야 하는 내용을 고찰하였다. 먼저 연계해석 수행시 요구되는 지하수위 저하와 지반거동과의 관계에 대한 배경 이론을 알아보았으며, 이를 토대로 모델링 측면에서 해석결과에 영향을 미칠 수 있는 다양한 인자들을 선정하고, 선정된 영향인자에 대한 매개변수 연구를 수행하였다. 지하수위 저하가 동반되는 터널 시공조건에서의 유한요소석 모델링 결과는 지반의 불포화특성 고려여부가 가장 큰 영향을 미치는 것으로 나타났으며 본 고에서는 결과를 종합하여 연계해석 모델링시 중요하게 검토되어야 고려사항을 제시하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.668-671
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• 1997

In order to investigate the vibration characteristics of fluid-structure interaction problem, we modeled two identical rectangular plates coupled with bounded fluid. The fixed boundary condition along the plate edges and an ideal fluid were assumed. A commercial computer code, ANSYS was used to perform finite element analysis and FEM solutions were compared with the experimental results to modify the finite element model. As a result, comparison of FEM and experiment showed good agreement, and the transverse vibration modes, in-phase and out of-phase. were observed alternately in the tluid-coupled system. The effects of distance between two rectangular plates and width to length ratio on the fluid-coupled natural frequency were investigated. And it was found that the ormalized natural frequency of the fluid-coupled system monotonically increased with an increase in the number of modes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.767-770
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• 2006

To predict vibrational energy density of simple structural-acoustic coupled systems in medium-to-high frequency ranges, Power Flow Finite Element Method(PFFEM) is used, and PFFEM sofiware, PFADS has been developed for the vibration predictions and analysis of coupled system structures in medium-to-high frequency ranges. However, it needs to consider vibro-acoustic coupled analysis to get more accurate results. Prior to implement vibro-acoustic coupled analysis functions in PFADS, research on vibro-acoustic coupled analysis using PFFEH is performed for simple models. These predictions include the indirect transmission path associated, and also the direct transmission path, and the formulation is extended to structural system model by using appropriate modifications to structural-acoustic and acoustic-acoustic joint matrices. Concerning the waves in plate and acoustic, it is possible to calculate the structural-acoustic full matrix of a model using PFFEM, and the formulations developed are implemented for two rooms surrounded by plates.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.369-389
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• 2014

Two-layer coupled or composite beams with discrete shear connectors of finite dimensions are commonly encountered in pre-fabricated construction. This paper presents the development of simplified closed-form solutions for such type of coupled beams for practical applications. A new coupled beam element is proposed to represent the unconnected segments in the beam. General solutions are then developed by an inductive method based on the results from the finite element analysis. A modification is subsequently considered to account for the effect of local deformations. For typical cases where the local deformation is primarily concerned about its distribution over the depth of the coupled beam, empirical modification factors are developed based on parametric calculations using finite element models. The developed analytical method for the coupled beams in question is simple, sufficiently accurate, and suitable for quick calculation in engineering practice.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.111-114
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• 2007

Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM) are used to perform aerodynamics analysis and structure analysis. For the fluid-structure interaction analysis, each technology should be considered as well. The process of aerodynamics-structure coupled analysis can be applied to various integrated analyses from many research fields. In this study, the aerodynamics-structure coupled analysis is performed for the missile at high angle of attack condition through the use of Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM). For this purpose, the aerodynamics-structure coupled analyses procedure for the missile are established. The results of the integrated analysis are compared with rigid geometry of the missile and the effect of the deformation will be addressed.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1201-1210
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• 2002

A penalty frame method is proposed for the coupled analysis of finite elements with independently modeled substructures. Although previously reported hybrid interface method by Aminpour et al (IJNME, Vol 38, 1995) is accurate and reliable, it requires non-conventional special solution algorithm such as multifrontal solver. In present study, an alternative method has been developed using penalty frame constraints, which results in positive symmetric global stiffness matrices. Thus the conventional skyline solver or band solver can be utilized in the solution routine, which makes the present method applicable in the environment of conventional finite element commercial software. Numerical examples show applicability of the present method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.150-155
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• 2000

In this study, deformation analysis for solid-liquid coupled structure has been performed using explicit finite element program In order to model the behavior of liquid, SPH (Smooth Particle Hydrodynamics) algorithm was adopted. Crash test and simulation for the hydro-type impact energy absorber were given as an example of industrial application. The obtained good correlation between the test results and simulation reveals that the proposed method could be used effectively for the structural analysis of solid-liquid coupled problems

• Structural Engineering and Mechanics
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• 제16권6호
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• pp.655-674
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• 2003

Investigated in this study are the natural vibration characteristics of the coaxial cylindrical shells coupled with a fluid. Theoretical method is developed to find the natural frequencies of the shell using the finite Fourier series expansion, and their results are compared with those of finite element method to verify the validation of the method developed. The effect of the fluid-filled annulus and the boundary conditions on the modal characteristics of the coaxial shells is investigated using a finite element modeling.

• Structural Engineering and Mechanics
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• 제14권5호
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• pp.505-520
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• 2002

Based on the modal coordinates of the structure, a finite-element and CQC (complete quadratic combination) method for analyzing the coupled buffeting response of long-span bridges is presented. The formulation of nodal equivalent aerodynamic buffeting forces is derived based on a reasonable assumption. The power spectral density and variance of nodal displacements and elemental internal forces of the bridge structure are computed using the finite-element method and the random vibration theory. The method presented is very efficient and can consider the arbitrary spectrum and spatial coherence of natural winds and the multimode and intermode effects on the buffeting responses of bridge structures. A coupled buffeting analysis of the Jiangyin Yangtse River Suspension Bridge with 1385 in main span is performed as an example. The results analyzed show that the multimode and intermode effects on the buffeting response of the bridge deck are quite remarkable.