• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.69-77
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• 1999

Roll profile design in spape rolling with a complex-shaped part depends on the designer's experience, which is general, is acquired through costly trial-and-error process. As a prerequisite for developing a scientific approach to roll profile design, we present a finite element model to simulate 3-D deformation of complex-shaped parts occuring in multi-pass sequence. Demonstrated is the process model's capability to deal with rolling of a complex-shaped part.

• Computers and Concrete
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• v.6 no.3
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• pp.187-202
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• 2009

This paper focuses on the flexural behavior of RC beams externally strengthened with Carbon Fiber Reinforced Polymers (CFRP) fabric. A non-linear finite element (FE) analysis strategy is proposed to support the beam flexural behavior experimental analysis. A development system (QUEBRA2D/FEMOOP programs) has been used to accomplish the numerical simulation. Appropriate constitutive models for concrete, rebars, CFRP and bond-slip interfaces have been implemented and adjusted to represent the composite system behavior. Interface and truss finite elements have been implemented (discrete and embedded approaches) for the numerical representation of rebars, interfaces and composites.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.2
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• pp.65-72
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• 2003

Composite sabot can increase the penetration performance of APFSDS projectile by reduction of the sabot weight. However, it has a thick-sectioned lamination and the lamination structure is different from those of the conventional composite parts. In this study, modeling technique for a thick and radially-laminated composite part has been applied in the finite element analysis of composite sabot. Four models of composite lamination for the sabot have been proposed and evaluated for their structural strength.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.4
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• pp.1-7
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• 1998

This paper describes a meshless of element-free method based on fuzzy knowledge processing. To efficiently simulate complicated physical phenomena with dynmics and non-linear ploblem using computational mechanics, special method is required such as parallel processing or adaptive analysis techniques. However, the conventional finite element method is too complicated to be employed in the above cases. In order to reduce the above complexity of the conventional finite element analysis systms, the so called meshles finite elements as an input information have been stuided. Node is generated if its distance form existing node points is similar to the node spacing fuction at the point. The node spacing function is well controlled by the fuzzy knowledge processing Practical performances of the present system are demonstrated through several three-dimensional(3D) problems.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.126-128
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• 2005

This paper presents a 3-D finite element analysis of a magneto-thermal coupled problem with moving conductor. In the magnetic and thermal analyses, temperature-dependent magnetic and thermal material properties were considered. Transient finite element method for analysis of moving conductor needs many number of elements and much time to make calculation. Therefore, in this paper, finite element formulation derived from quasi-state is adopted. Finite element results were compared with the experimental results. The results demonstrate that this approach is suitable to solve the magneto-thermal coupled problem.

• Journal of Powder Materials
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• v.27 no.4
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• pp.318-324
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• 2020

In the present work, an explicit finite element analysis technique is introduced to analyze the thermal stress fields present in the additive manufacturing process. To this purpose, a finite element matrix formulation is derived from the equations of motion and continuity. The developed code, NET3D, is then applied to various sample problems including thermal stress development. The application of heat to an inclusion from an external source establishes an initial temperature from which heat flows to the surrounding body in the sample problems. The development of thermal stress due to the mismatch between the thermal strains is analyzed. As mass scaling can be used to shorten the computation time of explicit analysis, a mass scaling of 108 is employed here, which yields almost identical results to the quasi-static results.

• Structural Engineering and Mechanics
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• v.13 no.3
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• pp.345-353
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• 2002

Three noded plate and shell finite element and 3D beam element in conjunction with Lanczos method are used for studying the effect of boat tail angle on the free vibration characteristics of a typical payload fairing for three different cylinder diameters with height to diameter ratio 1.5. Configurations without boat tail structural member are also studied. One half of the one side fairing structure is considered for the analysis and symmetric boundary conditions are used.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1439-1450
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• 1995

Bellows is a familiar component in piping systems as it provides a relatively simple means of absorbing thermal expansion and providing system flexibility. In routine piping flexibility analysis by finite element methods, bellows is usually considered to be straight pipe runs modified by an appropriate flexibility factor; maximum stresses are evaluated using a corresponding stress concentration factor. The aim of this study is to develop a bellows finite element, which similarly includes more complex shell type deformation patterns. This element also does not require flexibility or stress factors, but evaluates more detailed deformation and stress patterns. The proposed bellows element is a 3-D, 2-noded line element, with three degrees of freedom per node and no bending. It is formulated by including additional 'internal' degrees of freedom to account for the deformation of the bellows corrugation; specifically a quarter toroidal section of the bellows, loaded by axial force, is considered and the shell type deformation of this is include by way of an approximating trigonometric series. The stiffness of each half bellows section may be found by minimising the potential energy of the section for a chosen deformation shape function. An experiment on the flexibility is performed to verify the reliability for bellows finite element.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.2
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• pp.230-235
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• 2009

This paper describes an automatic finite element mesh generation for finite element analysis of three-dimensional structures. It is consisting of fuzzy knowledge processing, bubble meshing and solid geometry modeler. This novel mesh generation process consists of three subprocesses: (a) definition of geometric model, i.e. analysis model, (b) generation of bubbles, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Bubble is generated if its distance from existing bubble points is similar to the bubble spacing function at the point. The bubble spacing function is well controlled by the fuzzy knowledge processing. The Delaunay method is introduced as a basic tool for element generation. Automatic generation of finite element for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for 3D geometry.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.06a
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• pp.111-131
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• 1996

In order to analyze stamping processes and to select optimum material properties of sheet steels for customer lines, 3-dimensional finite element analysis software were used. Commercial explicit finite element code, PAM-STAMP, was able to simulate 3-dimensional press formed parts with good accuracy and gave some useful results by orthogonal array experiments. Deformation of draw-bead were predicted by ABAQUS accurately, so that material selection for those parts by simulation were possible.