• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.4
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• pp.43-49
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• 2007

The reinforced concrete slab is one of main structure members in the construction industry sector. However, most of researches regarding to RC slabs have been focused on two-dimensional Mindlin-type plate element on the basis of laminated plate theory since three-dimensional solid element has a lot of difficulties in finite element formulation and costs in CPU time. In reality, the RC slabs are subjected to dynamic loads like a heavy traffic vehicle load, and thus should insure the safety from the static load as well as dynamic load. Once we can estimate the dynamic behaviour of RC slabs exactly, it will be very helpful for design of it. In this study, the 20-node solid element has been used to analyze the dynamic characteristics of RC slabs with clamped edges. The elasto-visco plastic model for material non-linearity and the smeared crack model have been adopted in the finite element formulation. The applicability of the proposed finite element has been tested for dynamic behaviour of RC slabs with respect to characteristics of concrete materials in terms of cracking stress, crushing strain, fracture energy and Poisson's ratio. The effect on dynamic behaviour is dependent on not crushing strain but cracking stress, fracture energy and Poisson's ratio. In addition to this, it is shown the damping phenomenon of RC slabs has been identified from the numerical results by using Rayleigh damping.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.06a
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• pp.5-15
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• 1997

It is the objective of this study that by conducting the serni-solid extrusion using A12024, the effect of various process variables on the quality of extruded product and extrusion force is understood. The results of experiment are compared with those of finite element simulation in order to verify the effectiveness of the developed FE-simulation code. In order to simulate densification in the deformation of serni-solid material, the semi-solid material is assumed to be composed of solid region as porous skeleton following compressible visco-plastic model and liquid region following Darcy's equation for the liquid flow saturated in the interstitial space. Then the flow and deformation of the semi-solid alloy are analyzed by coupling the deformation of the porous skeleton and the flow of the eutectic liquid. It is assumed that initial solid fraction is homogeneous. Yield and plastic potential function presented by Kuhn and constitutive model developed by Gunasekera are used for solid skeleton.

• Structural Engineering and Mechanics
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• v.11 no.4
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• pp.443-460
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• 2001

This paper presents an effective application of a variable-node axisymmetric solid element designated as AQV (Axisymmetric Quadrilateral Variable-node element). The variable-node element with physical midside nodes helps to overcome some problems in connecting the different layer patterns on a quadrilateral mesh in the adaptive h-refinement. This element alleviates the necessity of imposing displacement constraints on irregular (hanging) nodes in order to enforce the inter-element compatibility. Therefore, the elements with variable mid-side nodes can be used effectively in the local mesh refinement for the axisymmetric structures which have stress concentrations. A modified Gaussian quadrature should be adopted to evaluate the stiffness matrices of the variable-node elements mainly because of the slope discontinuity of assumed displacement within the elements. Some numerical examples show the usefulness of variable-node axisymmetric elements in the practical application.

• Structural Engineering and Mechanics
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• v.3 no.4
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• pp.325-340
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• 1995

The iterative procedure to use the nonconforming elements in elasto-plastic problems is established and applied to the variable node transition solid element developed for the automated three-dimensional local mesh refinement. Through numerical tests, the validity and performance of the element are examined. As the nonlinear iterative procedure presented in this paper is accomplished for the general three-dimensional case, it can also be easily applied to the two-dimensional elements such as membranes, plates and shells.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.168-173
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• 1992

In the design and construction of underground structures, it is essential to accurately predict the structural behavior of the fluid-saturated ground during and after excavation. Terzaghi and Biot established the theory for the behavior of such two phase material. For the purpose of analysing the saturated porous solid system, finite element procedure provides a powerful tool. In this paper, a finite element analysis procedure based upon Biot's theory is presented to evaluate the deformation of solid skeleton and pore pressure of entraped fluid. Teraghi's onf-dimensional and Gibson's two-dimensional problems are solved using Q4 and Q8 element to verify the program validity.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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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

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.3-10
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• 1993

A new three-dimensional transition solid elements was presented for the automated three-dimensional adaptive h-refinement where the steep stress gradient exists. To be consistent with 8-node solid element with nonconforming modes in accuracy, these transition elements were improved through the addition of the associated nonconforming modes. Numerical examples show that the performance of the element and the applicability to 3D adaptations are satisfactory.

• Computational Structural Engineering
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• v.11 no.4
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• pp.169-176
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• 1998

불연속적 거동이 탁월한 벽식 프리캐스트 구조물을 해석하기 위한 방법으로 유한요소법과 강체요소법 등이 있으나, 이들 해석법은 접합부의 거동을 정확히 반영하지 못하고 있다. 본 연구에서는 패널은 강체적 거동을 하고, 판널과 판널 사이의 접합부는 고체적 거동을 가정하는 강체-고체 복합모델(Coupled Model by Rigid and Solid bodies)에 의한 해석법을 제안하며, 간단한 모델의 예를 통해 검증하였다.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.1
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• pp.89-99
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• 1993

A solid modeller was developed in this paper. Representation scheme of modelling is nonmanifold B-rep. While namy B-rep modellers use edges as basic element of modelling, this modeller is triangle-based. New modelling element, split triangle that is composed of 3 pure half-edges and has no information about the adjoining triangles, was defined to enlarge the range of representation. Corresponding algorithms for Boolean set operations were also developed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.3-9
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• 2001

In this study, the geometric modeling has been conducted for the current lower end fitting and 2 candidates using three-dimensional solid modeler, Solidworks. Then, the three-dimensional stress analysis using the finite element method has been performed. The evaluation for the mechanical integrity of 2 candidates has been performed based on the stress distribution obtained from the finite element analysis.