• Architectural research
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• v.16 no.2
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• pp.67-74
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• 2014

Free vibration analysis of thin shells is carried out by using isogeometric approach. For this purpose, a thin shell element based on Kirchhoff-Love shell theory is developed. Non-uniform rational B-spline surface (NURBS) definition is introduced to represent the geometry of shell and also used to derive all terms required in the isogeometric element formulation. Gauss integration rule is used for stiffness and mass matrices. The present shell element is then applied to examine vibrational behaviours of thin plate and shell structures. From numerical results, it is found be that reliable natural frequencies and associated mode shapes of thin shell structures can be predicted by the present isogeometric shell element.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.653-659
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• 2003

The main objective of this study is to estimate the hydrodynamic forces and to investigate the nonlinear behaviors of fluid motion around the oscillating body on or below a free surface. We have developed a composite grid method to solve the radiation problems. This method is applied to numerical computation of the radiation forces generated by the oscillating body. The numerical results obtained by the present method are compared with the experimental data and a linear potential theory. As a result, we can confirm the accuracy of the present method. Finally, we have evaluated the effect of viscosity on the hydrodynamic forces acting on the oscillating body.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.472-476
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• 2003

A real train load fluctuates along the track because of complicated movements(Bouncing, Rolling, Pitching and Yawing) and rail conditions. This research has for its object in development of a numerical train load model including fluctuation characteristics of lateral forces. It is based on Klingel movement theory of a wheelset on straight track. it presents a propriety of application by comparison between a 3D-Numerical analysis result using this train load model and a measured data. And this paper presents further study subject to improve a method about the train load modeling.

• Journal of Korean Society of Steel Construction
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• v.12 no.6
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• pp.691-700
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• 2000

A powerful analytical procedure and strain energy analysis to investigate the free vibration of antisymmetric angle-ply laminated plates, having one pair of opposite edges simply supported, are develped on the basis of the Yang, Norris and Stavsky (YSN) theory. The equation of motion of the plate are solved by the use of collocation method. A range of results are presented for plates to show the effects of modulus ratio and number of layers on natural frequency. In addition, an analysis of the strain energy distributions is used as an aid for the better understanding of the vibration characteristics of the plates.

• Structural Engineering and Mechanics
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• v.52 no.1
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• pp.137-147
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• 2014

The present paper deals with the first ply failure analysis of the laminated composite plates under various static and dynamic loading conditions. Static analysis has been carried out under patch load and triangular load. The dynamic failure analysis has been carried out under triangular pulse load. The formulation has been carried out using the finite element method and a computer code has been developed. The first order shear deformation theory has been applied in the present formulation. The displacement time history analysis of laminated composite plate has been carried out and the results are compared with those published in literature to validate the formulation. The first ply failure load for laminated composite plates with various lamination schemes under static and dynamic loading conditions has been calculated using various failure criteria. The failure index-time history analysis has also been carried out and presented in this paper.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.69-77
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• 1999

The stabbing guide is often used to guide an add-on pile into an existing pile in offshore jacket installation. It provides a pile alignment for a welding tie-in in static condition as well. Even stabbing guide is an essential component in pile installation, it is not considered as a permanent offshore structure. In this regard, there is not a define design guideline proposed. In API RP 2A WSD, it briefly define the design considerations of stabbing guide. The failure of stabbing guide can cause a greate economical loss and a serious impact to the project schedule. Stabbing guide design should consider many factors considering actual work conditions for both static and dynamic situations. In the paper, a design method is proposed by appling the plate theory and it is confirmed numerically with FEM modeling. The geometry of stabbing guide is assumed as a cylinder shape with various wall thickness and effective length. The various thickness, effective length and pile size are compared for stable stabbing guide design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.11-18
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• 2004

In this paper, an efficient model reduction scheme is presented for large scale dynamic systems. The method is founded on a modal analysis in which optimal eigenvalue is extracted from time samples of the given system response. The techniques we discuss are based on classical theory such as the Karhunen-Loeve expansion. Only recently has it been applied to structural dynamics problems. It consists in obtaining a set of orthogonal eigenfunctions where the dynamics is to be projected. Practically, one constructs a spatial autocorrelation tensor and then performs its spectral decomposition. The resulting eigenfunctions will provide the required proper orthogonal modes(POMs) or empirical eigenmodes and the correspondent empirical eigenvalues (or proper orthogonal values, POVs) represent the mean energy contained in that projection. The purpose of this paper is to compare the reduced order model using Karhunen-Loeve expansion with the full model analysis. A cantilever beam and a simply supported plate subjected to sinusoidal force demonstrated the validity and efficiency of the reduced order technique by K-L method.

• Journal of Korean Association for Spatial Structures
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• v.1 no.2 s.2
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• pp.101-110
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• 2001

A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an elastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of reduced model test. Satisfactory agreement is found between theory and experiment.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.1
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• pp.57-65
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• 2008

Superplastic forming/diffusion bonding(SPF/DB) processes with inner contact were analyzed using a 3-D rigid visco-plastic finite element method. A constant-triangular element based on membrane approximation and an incremental theory of plasticity are employed for the formulation. The hierarchical search algorithm for the contact searching has been applied. The algorithms for contact force processing were designed to handle equally well contact between deformable bodies, as well as rigid bodies. The plate of three and four sheets for 3-D SPF/DB model are analyzed using the developed program. The validity for the analysis is verified by comparison between analysis, experiment and results in the literature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.25-32
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• 1989

A finite element program for material nonlinear fracture analysis of reinforced concrete shell was developed. This method can be used to trace the load-displacement response and crack propagation through the elastic and inelastic ranges. A layered isoparametric flat finite element considering the coupling effect between the in-plane and the bending action was developed. Mindlin plate theory taking account of transverse shear deformation was used. The validity of the present program was proved by comparing the numerical results with Hedgren's experimental data.