• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1245-1251
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• 2005

The deformation modulus is an important variable which can be used to predict settlement of structures, analyze horizontal directions of piles and design roads. Though to predict deformation modulus relationships using standard penentration test N-value and undrained shear strength were suggested , these relationships are not appropriate in domestic areas because these relationships are based on foreign areas. Therefore, in this study, with field test results, reasonable equations in domestic area are suggested to estimate deformation modulus.

• International Journal of CAD/CAM
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• v.1 no.1
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• pp.23-32
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• 2002

In this paper, a new technique of space deformation for parametric surfaces with so-called extension function (EF) is presented. Firstly, a special extension function is introduced. Then an operator matrix is constructed on the basis of EF. Finally the deformation of a surface is achieved through multiplying the equation of the surface by an operator matrix or adding the multiplication of some vector and the operator matrix to the equation. Interactively modifying control parameters, ideal deformation effect can be got. The implementation shows that the method is simple, intuitive and easy to control. It can be used in such fields as geometric modeling and computer animation.

• Journal of Ship and Ocean Technology
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• v.7 no.4
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• pp.41-49
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• 2003

Welding deformation reduces the accuracy of ship hull blocks and decreases productivity due to the need for correction work. Preparing an error-minimizing guide at the design stage will lead to higher quality as well as higher productivity. Therefore, developing a precise method to predict the weld deformation is an essential part of it. This paper proposes an efficient method for predicting the weld deformation of complicated structures based on the inherent strain theory combined with the finite element method. A simulation of a stiffened panel confirmed the applicability of this method to simple ship hull blocks.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.308-315
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• 2006

Most of seismic designs of major structures up to now have been performed by the traditional 'force-based design' approaches. However, they are not so efficient to evaluate the structural deformations by potential nonlinear behaviors which are directly related with the damages or performance levels during earthquakes. Lately, based on this situation, various kinds of new seismic design approaches based on the deformation, which is called 'displacement-based design' procedures, have been proposed. In this paper, most of detail techniques and procedures of the new design methods in the literature are comparatively reviewed and evaluated first, followed by a series of design examples of typical bridge structures. Comparing the results with those of the existing force-based design, the improved levels of performance and economy of the displacement-based seismic design have been validated.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.3
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• pp.61-71
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• 1998

A performance-based seismic design method for reinforced concrete building structures being developed in Japan is outlined. Technical and scientific background of the performance-based design philosophy as well as recently developed seismic design guidelines are is presented, in which maximum displacement response to design earthquake motion is used as the limit-state design criteria. A method of estimating dynamic response displacement of the structures based on static nonlinear analysis is described. A theoretical estimation of nonlinear dynamic response considering the characteristics of energy input to the system is described in detail, which may be used as the standard method in the new performance-based code. A desing philosophy not only satisfying the criteria but also evaluating seismic capacity of the structures is also introduced.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.15-22
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• 1999

In this study, a machining error estimation system far vertical lathes with structural deformation and geometric errors, is realized based on the virtual manufacturing technologies. The positional and directional errors of cutting tool are determined by considering the geometric errors and dimensions of machine components and by introducing the equilibrium condition between the cutting force and structural deformation. Especially, the machining errors of vertical lathes are estimated by using the prescribed cutting test(JIS B 6331). The system can be implemented to evaluate the machining accuracies of vertical lathes at the design process and to design the high precision vertical lathes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.146-151
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• 1998

In this study, a machining error estimation system for vertical lathes with structural deformation and geometric errors, is realized based on the virtual manufacturing technologies. The positional and directional errors of cutting tool are determined by considering the geometric errors and dimensions of machine components and by introducing the equilibrium condition between the cutting force and structural deformation. specially, the machining errors of vertical lathes are estimated by using the prescribed cutting test(JIS B 6331). The system can be implemented to evaluate the machining accuracies of vertical lathes at the design process and to design the high precision vertical lathes.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.199-204
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• 2000

A cylindrical brake device with plastic deformation is designed to stop the object moving at high velocity. Baseline model is determined based on the design specification and analytic solutions. Using finite element method, effects of various design parameters, such as thickness of the cylinder, clearance between cylinder and rod, and cone angle, to the performance of the brake device are investigated. Cone-type brake device shows better performance than cylindrical brake device with constant thickness in that plastic hinges are generated sequentially from impact end to fixed boundary, thus increasing the reliability of braking operation.

• Journal of the Korean Geophysical Society
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• v.7 no.4
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• pp.277-282
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• 2004

Creep deformation of concrete is often responsible for excessive deflection at loads which can compromise the performance of elements within structures. Hence, the prediction of the magnitude and rate of creep strain is an important requirement of the design process and management of structures. Although laboratory tests may be undertaken to determine the deformation properties of concrete, these are time-consuming, often expensive and generally not a practical option. Therefore, relatively simple empirically based national design code models are relied upon to predict the magnitude of creep strain.This paper reviews the accuracy of creep predictions yielded by eight commonly used international "code type" models, all of which do not consider the same material parameters and yield a range of predicted strains, when compared with actual strains measured on a range of concretes in seventeen different investigations. The models assessed are the: SABS 0100 (1992), BS 8110 (1985), ACI 209 (1992), AS 3600 (1998), CEB-FIP (1970, 1978 and 1990) and the RILEM Model B3 (1995). The RILEM Model B3 (1995) and CEB-FIP (1978) were found to be the most and least accurate, respectively.

• Journal of Ocean Engineering and Technology
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• v.23 no.3
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• pp.1-5
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• 2009

It is necessary to develop an efficient optimization technique to optimize engineering structures that have given design spaces, discrete design values, and several design goals. In this study, an optimum algorithm based on the genetic algorithm was applied to the multi-object problem to obtain an optimum solution that simultaneously minimizes the structural weight and construction cost of panel blocks in ship structures. The cost model was used in this study, which includes the cost of adjusting the weld-induced deformation and applying the deformation control methods, in addition to the cost of the material and the welding cost usually included in the normal cost model. By using the proposed cost model, more realistic optimum design results can be expected.