• 한국수학교육학회지시리즈B:순수및응용수학
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• 제17권4호
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• pp.321-332
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• 2010

In this paper, we experiment image warping and morphing. In image warping, we use radial basis functions : Thin Plate Spline, Multi-quadratic and Gaussian. Then we obtain the fact that Thin Plate Spline interpolation of the displacement with reverse mapping is the efficient means of image warping. Reflecting the result of image warping, we generate two examples of image morphing.

• 대한기계학회논문집A
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• 제28권3호
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• pp.274-280
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• 2004

This paper presents the analysis fur the radial vibration characteristics of cylindrical piezoelectric transducers. Taking into account the piezoelectric anisotropy, the differential equations of piezoelectric radial motion have been derived in terms of radial displacement and electric potential. Applying mechanical and electric boundary conditions has yielded a characteristic equation for radial vibration. Numerical analysis also has been carried out by using the finite element method. Theoretical calculations of the fundamental natural frequency have been compared with the experimental observations for transducers of several sizes. Comparison with the previous report of theoretical analysis simplifying the piezoelectric anisotropy into isotropy concludes that isotropic analysis is a reasonable process to predict the vibration characteristics of piezoelectric transducers.

• 한국농공학회논문집
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• 제48권6호
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• pp.69-77
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• 2006

In this study, the large scaled model test improved by sand drain was carried out to clarify the internal behavior of the three-dimensional consolidation under different secondary consolidation periods. From the results of model test, the void ratio in the undrained side was lager than in the drained side. In addition, the unconfined compressive strength in the long-term consolidated specimen was larger than that in the short-term consolidated one. It was also found that the unconfined compressive strength was larger in the drained side than in the undrained side. These reasons are considered to be due to the large effective stress by quick pore water pressure dissipation by the short drainage distance in the drained side. Furthermore, in order to investigate the three-dimensional consolidation behavior of clay ground improved by the vertical drain method, the numerical analysis obtained from the three-dimensional elasto-viscous consolidation theory proposed by author (2006) were compared with the test results. It was found that during the three-dimensional consolidation process not only vertical displacement but also radial displacement occurs inside the specimen.

• 한국정밀공학회지
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• 제20권5호
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• pp.204-209
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• 2003

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important for dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations. Therefore, by modifying the constitutive equation fur a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation for radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed, Solutions were allowed fur comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.995-999
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• 1995

In spindle-bearing system, the displacement characteristics of the bearing by the load applied on the spindle are affected greatly by the assembling tolerance between the spindle and housing assembled to support the bearing. Also in spindle system of rotational operation, the compliance characteristic of the bearing is expected to be varied frequently by the thermal deformation of the spindle and the housing. To predict the thermal deformation of the spindle including heat generation of the bearing, we need to examine the effect on the compliance of spindle-bearing system by the assembling tolerance. In this paper, we proposed the load-displacement relation expression considering the effect which the variation of contact pressure due to the radial directional assembling tolerance between the bearing and the housing influences on the axial and radial directional displacement characteristics of the bearing. Furthermore, for several assembling systems of bearings and housings having all different assembling tolerances, we proposed a method to predict exactly the variation of the bearing preload which is sensitive to the thermal deformation by showing the propriety with experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.415-419
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• 2003

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important for dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data for the elastomeric bushing material was obtained and this data was used to derive the new load-displacement for radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.703-708
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• 2002

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of Elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation fur elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations and is hence unsuitable. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation fur radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.15-16
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• 2006

In-process surface roughness prediction is studied in this research. To implement in-process prediction, spindle displacement is introduced. Machined surface's roughness is assumed to be expressed in terms of spindle displacement. In-process measurement of spindle displacement is conducted using CCDS (cylindrical capacitive displacement sensor). Two prediction models are developed. One is simple linear model between measured surface roughness and values by spindle displacement. The other is multiple regression model including machining parameters like spindle speed, fee rate and radial depth of cut. Relation between machined surface roughness and roughness by spindle displacement are verified.

• 한국음향학회지
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• 제21권8호
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• pp.757-765
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• 2002

본 논문은 해석과 실험을 통하여 구형 압전 변환기의 점대칭 방사모드 진동 특성을 규명하는 것을 목적으로 한다. 반경 방향 좌표와 시간의 함수인 반경 방향 변위와 전기 퍼텐셜로 표현되는 지배방정식을 구성한다. 역학적 경계조건과 전기적 경계조건을 적용하여 방사 진동의 특성방정식을 유도한다. 이 식을 이용하여 압전 고유진동수를 계산하고, 그 결과를 측정 결과와 비교한다. 수치계산을 통하여 압전 공진과 탄성 공진의 차이, 구형 압전체의 반경 및 두께에 따른 고유진동수 등을 고찰한다. 그 결과 1차 방사모드의 고유진동수 크기는 압전현상으로 인해 작아지며 구형의 곡률 반지름이 커짐에 따라 지수함수적으로 작아지는 것을 알게 되었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 제4회 압출 및 인발가공 심포지엄
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• pp.99-106
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• 2001

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die Insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.