• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.1
• /
• pp.93-103
• /
• 1994

Two beam/column elements are developed in order to analyze the geometric nonlinear plane irames including the effects of internal hinge and transverse shear deformation. In the case of the first element (finite segment method), tangent stiffness matrix is derived by directly integrating the equilibrium equations whereas in the case of the second element (finite element method) elastic and goemetric stiffness matrices are calculated by using the hermitian polynomials including the effects of internal hinge and shear deformation as the shape function. Numerical results are presented for the selected test problems which demonstrate that both elements represent reliable and highly accurate tools.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.10 no.1
• /
• pp.27-36
• /
• 1990

Two beam/column elements in order to analyze the geometric nonlinear plane framed structures including the effects of transverse shear deformation and bending stretching coupling are developed. In the case of the first element (finite segment method), tangent stiffness matrix are derived by directly integrating the equilibrium equations whereas in the case of the second element (finite element method) elastic and geometric stiffness matrices are calculated by using the hermitian polynomials including shear deformation effect as the shape function. Both elements possess the usual six degree of freedoms. Numerical results are presented for the selected test problems which demonstrate that both elements represent reliable and highly accurate tools.

• Journal of Ocean Engineering and Technology
• /
• v.2 no.2
• /
• pp.71-77
• /
• 1988

For the collapse of structures due to the variable repeated load, two types of collapse mechanisms, i.e., incremental collapse and alternating plasticity, exist. Under the similar variable repeated loading conditions there exists shakedown state in the structures. In shakedown state, the number of plastic hinges are not increased and all further loading will be resulted in the elastic moment changes. Namely, under the shakedown state, structures do not collapse. In this investigation, shakedown analysis are performed by composing new computer programs. Basic theories employed to compose the programs are as follows. 1. Newton-Raphson methods are added to the existing matrix method for the plastic analysis. 2. An effort to construct the stiffness of axial and bending springs attached at both ends of the member has been made. By using the programs developed, it is possible to anticipate the collapse mechanisms (Incremental collapse, alternating plasticity). Lastly for the verification of performance of the program, demonstration examples have been solved and the results are compared with other sources.

• Computational Structural Engineering
• /
• v.4 no.1
• /
• pp.121-132
• /
• 1991

The purpose of this study is to analyze concentrically loaded reinforced concrete columns with the restrained effect having rectangular cross-section and general boundary conditions. Accordingly, this investigation is to construct a typical analytical model of the reinforced concrete columns with general boundary conditions. The mechanical components of the analytical model are to be rationally defined so as to model the actual behavior as closely as possible, and the ultimate strength of the reinforced concrete columns are investigated by end restrained effect.

• Journal of Korean Society of Steel Construction
• /
• v.16 no.5 s.72
• /
• pp.683-694
• /
• 2004

Advanced analysis and optimal design of semi-rigid space steel frames were presented. The advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. Material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and the parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. One by one, the member with the largest unit value evaluated using the LRFD interaction equation were placed adjacent to a larger member selected from the database. The objective function was assumed to be the weight of steel frame, while the constraint functions were load-carrying capacities, deflections, inter-story drifts, and the ductility requirements. The member sizes determined using the proposed method were compared to those derived from the conventional LRFD method.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1993.04a
• /
• pp.61-68
• /
• 1993

A computer program for free vibration analysis of plane framed structures has been developed by object oriented programming technique using C" language. The object oriented programming concepts such as object, class, method and inheritance are represented. The static and free vibration analyses for framed structures were satisfactorily performed by this program which consists of TOP, VECTOR, MATRIX, STRU, GUI and other classes. Numerical test shows the validity and capability of the present study which can be expandable to develop a general purpose object oriented finite element analysis program of structures ,res ,

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1998.10a
• /
• pp.201-207
• /
• 1998

In this study, a geometric nonlinear analysis formulation for spatial frames is developed using the 3D stability functions. For the formulation, the relationships of local and global coordinate systems in force, deformation, and the initial and current configurations of a frame are derived. The force-deformation relationship in global coordinate system is derived as well. The developed formulation is verified in each derivation by reducing the derived equations into 2D equations. The gradual plastification of connections and critical sections can be implemented effectively to this formulation for the complete second order inelastic advanced analysis of spatial frames.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.2
• /
• pp.197-206
• /
• 2003

The optimal design method in cooperation with a nonlinear elastic analysis method was presented. The proposed nonlinear elastic method overcame the drawback of the conventional LRFD method this approximately accounts for the nonlinear effect caused by using the moment amplification factors of and. The genetic algorithm uses a procedure based on the Darwinian notions of the survival of the fittest, where selection, crossover, and mutation operators are used to look for high performance among the sections of the database. They satisfy constraint functions and give the lightest weight to the structure. The objective function was set to the total weight of the steel structure. The constraint functions were load-carrying capacities, serviceability, and ductility requirement. Case studies for a two-dimensional frame, a three-dimensional frame, and a three-dimensional steel arch bridge were likewise presented.

• Computational Structural Engineering
• /
• v.7 no.4
• /
• pp.69-83
• /
• 1994

An explicit finite element nonlinear formulation for very large deformations of plane frame structures is developed. The formulation is based on an updated material reference frame and hence a true stress-strain relationship can be directly applied to characterize the properties of material which is subjected to very large deformations. In the formulation, a co-rotational approach is applied to deal with the large rotations but small strain problems. Straight beam element is considered when the strain of an element is large. The element formulation is based on the small deflection beam theory but with the inclusion of the effect of axial force. The element equations are constructed in an element local coordinate system which rotates and translates with the element, and then transformed to the global coordinate system. Several numerical examples are analyzed to validate the presented formulation.

• Computational Structural Engineering
• /
• v.9 no.3
• /
• pp.187-197
• /
• 1996

An explicit direct time integration method based solution algorithm is presented to predict dynamic buckling response of Euler column. On the basis of large deflection beam theory, a plane frame finite element is formulated and implemented into the solution algorithm. The element formulation takes into account geometrical nonlinearity and overall buckling of steel structural frames. The solution algorithm employs the central difference method. Using the computer program developed by the author, dynamic instability behavior of Euler column under impact loading is investigated by considering the time variation of load, load magnitude, and load duration. The free vibration of Euler column caused by a short duration impact load is also studied. The validity and efficiency of the present formulation and solution algorithm are verified through illustrative numerical examples.