• Title/Summary/Keyword: Surface Modeling

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Representation of Sweep Surface in Bicubic Spline surface Form (쌍3차 스플라인곡면 식에 의한 이동곡면의 표현)

  • 전차수;조형래;박세형
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.4
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    • pp.1005-1012
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    • 1995
  • This paper proposes a new approach for modeling sweep surfaces. The overall modeling procedure consists of following steps : (1)remeshing the section curves based on the curve lengths ; (2)remeshing the guide curve and the boundary curves based on a given sweeping rule ; (3)obtaining intermediate section curves at the remeshed points of the guide curve by blending the initial section curves ; (4)compensation of the intermediate section curves ; (5)interpolating the initial and intermediate curves using Hermite interpolant. The resulting sweep surface is expressed in a G$^{2}$ bicubic parametric spline surface.

Addendum Surface Modeling in Draw Die Design for Stamping Automotive Panels (자동차 프레스 패널 성형을 위한 드로 금형의 어덴덤 곡면 모델링)

  • Chung, Yunchan
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.6
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    • pp.1018-1024
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    • 2013
  • In the process of draw die design for stamping automotive press panels, the addendum surfaces generated in metal forming simulation software cannot be used in downstream processes such as machining and making draw dies because simulation tools use simple discrete models for the surface geometry. The downstream processes require more precise and continuous geometric models such as NURBS surfaces. Generally, automotive die engineers manually regenerate the addendum surface geometry using the discrete model. This paper presents an automated geometric modeling process for generating addendum surfaces using draft surface models. The design parameters of the section curve for the addendum surfaces are extracted automatically from the draft geometry. Using the extracted design parameters, smooth addendum surfaces are generated automatically as NURBS surfaces. The generated surfaces are $G^1$ continuous with the part surface and the binder surface, and can be used in downstream processes.

A Study on The Construction of 3-Dimensional Edge Blend Surface Modeling (곡면 모델링에서 3차원 경계 곡면 블렌드 구성에 관한 연구)

  • 이창억
    • Journal of the Korean Professional Engineers Association
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    • v.27 no.3
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    • pp.121-131
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    • 1994
  • It is very difficult to partially describe the hull shape made up of 3-dimensional free form surface. With computerizing skill in ship design, the geometric modeling technique has been developed. In hull shape modeling, the blending technique has not yet been adapted to the hull shape surface has a variable curvature. By adapting the blend surface, small surface on drawing plane is to be softly blended with given hull surface and a projecting part. This study has adapted to the ship design one of the blending methods by which offsets data of the blend surface can be obtained by the input of blend radius on two base surfaces.

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Integration of Geometrically Exact Shell Finite Element With Trimmed Surface Modeling base on the NURBS (기하학적으로 정확한 셀 유한요소와 NURBS기반의 Trimmed Surface 모델링과의 연동)

  • Choi Jin-Bork;Roh Hee-Yuel;Cho Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.794-801
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    • 2006
  • The linkage framework of geometric modeling and analysis based on the NURBS technology is developed in this study. The NURBS surfaces are generated by interpolating the given set of data points or by extracting the necessary information to construct the NURBS surface from the IGES format file which is generated by the commercial CAD systems in the present study. Numerical examples shows the rate of displacement convergence according to the paramterization methods of the NURBS surface. NURBS can generate quadric surfaces in an exact manner. It is the one of the advantages of the NURBS. A trimmed NURBS surface that is often encountered in the modeling process of the CAD systems is also presented in the present study. The performance of the developed geometrically exact shell element integrated with the exact geometric representations by the NURBS equation is compared to those of the previous reported FE shell elements in the selected benchmark problems.

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Surface Deformation by using 3D Target Curve for Virtual Spatial Design (가상 공간 디자인을 위한 3차원 목표곡선을 이용한 곡면 변형)

  • Kwon, Jung-Hoon;Lee, Jeong-In;Chai, Young-Ho
    • Journal of KIISE:Software and Applications
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    • v.33 no.10
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    • pp.868-876
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    • 2006
  • 2D input data have to be converted into 3D data by means of some functions and menu system in 2D input modeling system. But data in 3D input system for virtual spatial design can be directly connected to the 3D modeling data. Nevertheless, efficient surface modeling and deformation algorithm for the 3D input modeling system are not proposed yet. In this paper, problems of conventional NURBS surface deformation methods which can occur when applied in the 3D input modeling system are introduced. And NURBS surface deformation by 3D target curves, in which the designer can easily approach, are suggested. Designer can efficiently implement the virtual spatial sketching and design by using the proposed deformation algorithm.

Parametric Quantity Take-Off of Earthwork by Comparing the Use of Surface and Solid Models (Surface 및 Solid 방식의 비교를 통한 Parametric 기법의 토공물량산출 방법)

  • Hwang, Hee-Su;Lee, Jae-Hong;Kim, Tae-Young
    • Journal of KIBIM
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    • v.8 no.1
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    • pp.56-62
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    • 2018
  • There exists no precedented case of quantity take-off, using parametric modeling, from BIM-based irregular structures. Civil 3D provides earthwork quantity take-off based on surface modeling. Generally, designers should enter data into the specification additionally after extracting quantity estimation from earthwork modeling design. The objective of this report is to suggest the method from quantity take-off to specification of BIM-based earthwork quantities. We intend to investigate earthwork take-off method by Civil3D and explain why parametric information extraction is required for quantity estimation and specification and how information of earthwork quantity based on solid and surface modeling is connected to open quantity take-off module. It is highly expected that this suggestion would be the practical methodology of earthwork quantity take-off and specification in the field of civil engineering.

Modeling of functional surface using Polynomial Regression (다항식회귀분석을 이용한 기능성곡면의 모델링)

  • 윤상환;황종대;정윤교
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.376-380
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    • 2002
  • This research presents modeling of a functional surface which is a constructed free-formed surface. The modeling introduced in this paper adopts polynomial regression that is utilizing approximating technique. The measured data are obtained from measuring with Coordinate Measuring Machine. This paper introduces efficient methods of Reverse Engineering using Polynomial Regression.

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Shape Optimization of Shell Surfaces Based on Linkage Framework betweenGeometric Modeling and Finite Element Analysis (유한요소해석과 기하학적 모델링의 연동에 기초한 쉘 곡면의 형상 최적 설계)

  • Kim, Hyon-Cheol;Roh, Hee-Yuel;Cho, Maeng-Hyo
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1328-1333
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    • 2003
  • In the present study, an integrated framework of geometric modeling, analysis, and design optimization is proposed. Geometric modeling is based on B-spline surface representation. Geometrically-exact shell finite element is implemented in analysis module. Control points of the surface are selected as design variables for optimization, which can make the interaction easier between analysis and surface representation. Sequential linear programming(SLP) is adopted for the shape optimization of surfaces. For the computation of shape sensitivities, semi-analytical method is used. The developed integrated framework should serve as a powerful tool for the geometric modeling, analysis, and shape design of surfaces.

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Non-parametric Modeling of Cutter Swept Surfaces for Cutting Simulation (모의가공을 위한 공구 이동 궤적면의 비매개변수형 모델링)

  • 정연찬;최병규
    • Korean Journal of Computational Design and Engineering
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    • v.1 no.1
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    • pp.45-55
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    • 1996
  • This paper presents a new approach to non-parametric modeling of cutter swept surface (CSS) for cutting simulation. Instead of explicitly modeling cutter swept volumes, silhouette curves of the cutter surface are utilized in computing the z-value of the CSS at a grid point on the x,y-plane. The non-parametric evaluation of the CSS constitutes the integral part of 3-axis cutting simulation. The proposed method is more efficient than the existing ones in the case of conventional cutters (i.e., ball-end mills and flat-end mills), and more importantly, it enables the non-parametric modeling of the CSS for the round-end mills which was not possible with the existing methods.

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Surface Treatment Effect on the Toilet by Numerical Modeling and High Speed CCD Camera (수치모델과 고속 CCD 카메라를 이용한 세변기 표면 처리 효과 특성 해석)

  • Roh, Ji-Hyun;Do, Woo-Ri;Yang, Won-Kyun;Joo, Jung-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.44 no.1
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    • pp.32-37
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    • 2011
  • Numerical analysis is done to investigate the effect of surface treatment of a toilet on the cleanness. The surface treatment using plasma for the super-hydrophobic surface expects the self-cleaning effect of the toilet seat cover for preventing the droplets with a great quantity of bacteria during the toilet flushing after evacuation. In this study, the fluid analysis in the toilet during the flushing was performed by an ultrahigh-speed CCD camera with 1,000 frame/sec and the numerical modeling. And the spattering phenomenon from the toilet surface during urine was analyzed quantitatively by CFD-ACE+ with a free surface model and a mixed model of two fluids. If the surface tension of the toilet surface is weak, many urine droplets after collision bounded in spite of considering the gravity. The turbulence generated by the change of angle and velocity of urine and the variation of the collision phenomenon from toilet surface were modeled numerically.