• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.9 no.1
• /
• pp.11-23
• /
• 1989

This paper presents the results of the numerical analysis on the behaviour of mooring system of offshore guyed tower. Finite element method is used and geometric nonlinearities are considered in the analysis of mooring line. The governing equilibrium equations are derived by the principle of virtual work, and modified Newton-Raphson method and Newmark-${\beta}$ method are employed in response calculations. The drag and inertia effects of fluid are included using a Morrison type equation. The influences of changing typical parameters like initial inclination and tension of line at the guy attachment point, the length of clump weight, its unit weight and the anchor line length are examined. The effects of idealising the clump weight as a point load(lumped clump weight) on the behaviour of mooring lines are also discussed. Numerical examples demonstrate the validity and capability of the mathematical formulation.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.13 no.2 s.54
• /
• pp.153-164
• /
• 2009

In this paper, a method of increasing in load-carrying capacity is shown in two-span steel-concrete composite bridges strengthened by external tendons. An analytic expression for the increment of tendon force under external loads is derived using virtual work method for straight external tendons and a new rating factor equation is proposed. Considering the initial tendon force and its increment under external loads, an analytic procedure has been developed to calculate the number of tendons and the initial tendon force from the proposed rating factor equation. This method is used to verify a validity and rationality for an existing two-span composite steel-concrete bridge.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.11 no.2
• /
• pp.15-26
• /
• 1991

The lateral forces such as the earthquake and wind my cause the torsion to be coupled with the lateral bending in the gider, the cross-section of wich has only one axis of symmetry. This induces additional stresses especially in cables arranged in double-planes. Since this effect cannot be considered by using the conventional frame elements, the stiffness and the mass matrices of the geometrically nonlinear thin-walled frame element are developed in this study to model the girder. The equivalent modulus of elasticity proposed by Ernst is used for the cable elements. Verification of the present theory is made through a numerical example. Then, the free vibration of a three dimensional cable-stayed bridge is analyzed to study the coupled flexural-torsional behavior.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.10
• /
• pp.193-202
• /
• 1998

본 논문에서는 비선형 고체역학 이론에 대하여 특히 시간에 무관한 변형을 하는 초탄성 및 탄소성고체물질의 비선형 변형이론에 대하여 철저한 분석을 수행하였다 특히 비선형 변형의 해석방범론에 대하여 특별한 관심을 가지고 분석하였다. 비선형 변형해석 방법론으로 널리 논의되고 있는 증분뉴튼랩슨 방법에 대하여 수정된 개념을 제시하여 비선형 변형 해석의 정 확성을 향상시켰다.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.3 s.36
• /
• pp.509-523
• /
• 1998

A consistent finite element formulation and analytic solutions are presented for stability of thin-walled circular arch. The total potential energy is derived by applying the principle of linearized virtual work and including second order terms of finite semitangential rotations. As a result, the energy functional corresponding to the semitangential moment is newly derived. Analytic solutions for the out-of-plane buckling of symmetric thin-walled curved beam subjected to pure bending or uniform compression with simply supported boundary conditions are obtained. For finite element analysis, the cubic Hermitian polynomials are utilized as shape functions and $16{\times}16$ stiffness matrix for curved beam elements and $14{\times}14$ stiffness matrix for straight beam elements are evaluated, respectively. In order to illustrate the accuracy of this study, analytical and numerical results for lateral buckling problems of circular arch are presented and compared with available analytical solutions.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.5
• /
• pp.433-441
• /
• 2009

Generally, the events in nature have multi-disciplinary characteristics. To solve this problems, these days loosely coupled methods are widely applied because of advantage of solvers which are already developed and well proved. Those solvers use different mesh system, so transformation and mapping of data are vital in the field of fluid-structure interaction(FSI). In this paper, the interpolation of deformation which is used globally and compactly supported radial basis functions(RBF), and mapping of force which use principle of virtual work are examined for computing time and accuracy to compare ability with simple 3-D problem. As the results, interpolation scheme of compactly supported radial basis functions are useful to interpolation and mapping for large-scale airplane in FSI with a k-dimensional tree(kd-tree) which is a space-partitioning data structure for organizing points in a k-dimensional space.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.4 s.37
• /
• pp.657-666
• /
• 1998

This study presents an effective dual algorithm for the optimal design of steel structures with displacement constraints. The dual method can replace a primary optimization problem with a sequence of approximate explicit subproblems with a simple algebraic structure. Since being convex and separable, each subproblem can be solved efficiently by the dual method. Specifically, this study uses the principle of virtual work to obtain the displacement constraint equations with an explicit form and adds the linear regression equation expressing the relationships between the cross-section properties to the dual algorithm to reduce the number of design variables. Furthermore, this study deals with the discrete optimization problem to select members with the standard steel sections. Through numerical analyses, the proposed method will be compared with the conventional optimality criteria method.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.3 no.1
• /
• pp.41-54
• /
• 1999

For free vibration of non-symmetric thin-walled circular arches including restrained warping effect, the elastic strain and kinetic energy is derived by introducing displacement fields of circular arches in which all displacement parameters are defined at the centroid axis. The cubic Hermitian polynomials are utilized as shape functions for development of the curved thin-walled beam element having eight degrees of freedom. Analytical solution for in-plane free vibration behaviors of simply supported thin-walled curved beams with monosymmetric cross-sections is newly derived. Also, a finite element formulation using two noded curved beams element is presented by evaluating elastic stiffness and mass matrices. In order to illustrate the accuracy and practical usefulness of this study, analytical and numerical solutions for free vibration of circular arches are presented and compared with solutions analyzed by the straight beam element and the ABAQUS's shell element.

• Journal of Korean Society of Steel Construction
• /
• v.21 no.4
• /
• pp.393-401
• /
• 2009

The flexural-stiffness formula of the wale for the innovative prestressed support (IPS) system was precisely derived, and the equivalent beam stiffness was introduced for application in the actual design of the IPS wale. The cable tension forces of the IPS wale were calculated in both cases, and the axial-deformation effects were included and ignored, respectively. The central displacements of the 1-post, 2-post, 3-post, and 4-post IPS wales were calculated based on the principle of virtual work. The effects of the IPS wale length and cable inclination angle were also investigated using the derived central displacements. The simplified equivalent flexural stiffness of the IPS wale is presented herein for design purposes, and the validity of the proposed design formula was verified through its comparison with the FE and analysis solutions.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.10
• /
• pp.920-927
• /
• 2015

In this paper, numerical results of sectional analysis and stress recovery were compared with the results of VABS through the blade analysis library. The results of recovery analysis for one-dimensional model including the stiffness matrix is compared with the calculated three-dimensional stress results of three-dimensionial FEM based on the principle of virtual work. We discuss the configuration of the blade analysis library and compare verifications of numerical analysis results of VABS. Blade analysis library through dimensional reduction and stress recovery is intended to be utilized in conjunction with pre- and post-processing of the analysis program of the composite blade, high-altitude uav's wing, wind blades and tilt rotor blade.