• Journal of Welding and Joining
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• v.20 no.3
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• pp.60-66
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• 2002

Almost every die fur automobiles must be corrected or remodeled for minor geometrical changes or for better hardness characteristics by arc welding process. Although many other kinds of arc welding processes have been automated with robots, this molten metal deposition process for die remodeling still depend entirely on experienced welders. In this study, the database for bead shapes with respect to welding parameters are constructed by experiments to automate the molten metal deposition by arc welding process. And the changes of welding parameters for inclined base metal are studied to consider the effect of die geometries fur the welding process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.4
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• pp.251-258
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• 2011

The objective of this study is to propose two empirical correlations to predict the mass flow rate through an automotive block type thermostatic expansion valve and then to evaluate the correlations. The first correlation is deduced by modifying the basic equation of the orifice meter for the mass flow rate and the second correlation is deduced by using the Buckingham's ${\pi}$ theorem. The first correlation showed very good agreement on the measured data for R134a, given by Monforte. Average relative deviation and standard deviation of it are 2.5% and 1.6%, respectively. The second correlation agreed on the same measured data with a little greater deviations. The two correlations may apply to common expansion valves which have different geometrical sizes of the same shape.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.9-15
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• 2011

Any relative deformation between the cutting tool and the workpiece at machining point results directly in geometric and dimensional errors. The sources of relative deformations between the cutting tool and the workpiece at the contact point may be due to vibration, thermal deformation and cutting forces. In this paper, geometric error prediction of workpiece in turning has been investigated. To reach this goal, turning experiments are carried out according to selected cutting conditions. The variable cutting conditions are cutting speed, depth of cut and feed rate. The results will be useful as a guidance to select cutting conditions to improve the geometrical accuracy.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.13-22
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• 2008

For the accuracy correction of the micro-positioning industrial robot, micro-manipulator has been devised. The compliant mechanisms using piezoelectric actuators is necessary geometrically and structurally to be developed by the optimization approaches. The overall geometric advantage as the mechanical efficiencies of the mechanism are considered as objective functions, which respectively art the ratio of output displacement to input force, and their constraints are the vertical notion of supporting leg and the structural strength of manipulation. In optimizing the compliant mechanical amplifier, the sequential linear programming and an optimality criteria method are used for the geometrical dimensions of compliant bridges and flexure hinges. This paper presents the integrated design process which not only can maximize the mechanism feasibilities but also can ensure the positioning accuracy and sufficient workspace. Experiment and simulation are presented for validating the design process through the comparisons of the kinematical and structural performances.

• Journal of Ship and Ocean Technology
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• v.4 no.3
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• pp.13-20
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• 2000

In recent years, a number of successful nesting approaches have been developed by using the various heuristic algorithms, and due to their application potential several commercial CAD/CAM packages include a nesting module for solving the layout problems. Since a large portion of the complexity of the part nesting problem results from the overlapping computation, the geometric representation is one of the most important factors to reduce the complexity of the problem. The proposed part representation method can easily handle parts and raw materials with widely varying geometrical shape by using the redesigning modules. This considerably reduces the amount of processed data and consequently the run time of the computer. The aim of this research is to develop parametric macro for two-dimensional layout on the Auto-CAD system. Therefore, this research can be called "pre-nesting".ing".uot;.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.217-222
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• 2005

We come to know that recent seismic design is used in the railway bridge design by several analysis methods. The result of the analysis in each method is very different from each other, so very weak structures or very exaggerated structures are designed for earthquake. In this paper, by conducting seismic analysis of 25m PSC beam bridge mainly used in railway bridge, we compared and analyzed the difference of the result of the analysis methods. As a result, we could find that moment varies from $53\%\;to\;151\%$ depending on geometrical shape of bridge or seismic analysis method.

• Structural Engineering and Mechanics
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• v.54 no.4
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• pp.623-648
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• 2015

A numerical approach is presented for the analysis of the forced vibration of a rigid surface foundation with arbitrary shape. In the analysis, the foundation is discretized into a number of sub squaree-lements. The dynamic response within each sub-element is described by the Green's function, which is obtained by the Fourier-Bessel transform and Precise Integration Method (PIM). Incorporating the displacement boundary condition and force equilibrium of the foundation, it obtains a system of linear algebraic equation in terms of the contact forces within each sub-element. Solving the equation leads to the desired dynamic impedance functions of the foundation. Numerical results are obtained for foundation not only with simple geometrical configurations, such as rectangular and circular foundation, but also the case of irregularly shaped foundation. Several comparisons between the proposed approach and other methods are made. Very good agreement is reached. Also, parametric studies are carried out on the dynamic response of foundation. Addressed in this study are the effects of Poisson's ratio, material damping and contact condition of soil-foundation interface. Several conclusions are drawn the significance of the factors.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.9
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• pp.577-579
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• 2005

In this study, the automatic tracking algorithm tracing a human face is proposed by using YCbCr color coordinated information and its thermal properties expressed in terms of thermal indexes in an infra-red image. The facial candidates are separately estimated in CbCr color and infra-red domain, respectively with applying the morphological image processing operations and the geometrical shape measures for fitting the elliptical features of a human face. The identification of a true face is accomplished by logical 'AND' operation between the refined image in CbCr color and infra-red domain.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.368-373
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• 2004

Surface visualization can be useful, particularly for internet-based education and simulation system. Since the mesh data size directly affects the downloading and operational performance, the problem that should be solved for efficient surface visualization is to reduce the total number of polygons, constituting the surface geometry as much as Possible. In this paper, an efficient polygon reduction algorithm based on Stokes＇ theorem, and topology preservation to delete several adjacent vertices simultaneously for past polygon reduction is proposed. The algorithm is irrespective of the shape of polygon, and the number of the polygon. It can also reduce the number of polygons to the minimum number at one time. The performance and the usefulness for medical imaging application was demonstrated using synthesized geometrical objects including plane. cube. cylinder. and sphere. as well as a real human data.

• Journal of Ocean Engineering and Technology
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• v.26 no.2
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• pp.26-32
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• 2012

In this paper, the effects of irregular bead shapes on fatigue life were investigated. A modified S-N curve method was used to estimate the fatigue life, which considered the inherent multiaxiality caused by the geometrical feature produced by the welding process. The point method of the critical distance method was used to determine the fatigue effective stress. Three types of fillet joint models were tested in the fatigue experiments. For each model, real bead shapes were collected using a 3D laser scanner, and finite element analyses were performed. The results of the analyses with actual bead shapes were compared with those using an idealized bead shape model. The results of the present analytical methods showed good agreement with the experimental results.