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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Journal of Computational Design and Engineering
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Journal DOI :
Society of CAD/CAM Engineers
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Volume & Issues
Volume 5, Issue 4 - Dec 2000
Volume 5, Issue 3 - Sep 2000
Volume 5, Issue 2 - Jun 2000
Volume 5, Issue 1 - Mar 2000
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Triangular Mesh Generation Algorithm for Generating Nodes and Triangular Elements Concurrently
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 207~214
For last 20 years, a number of researches and developments on finite element mesh generation has been carried out and most of them are comported of node generation part and node generation part. However these algorithms are inefficient in mesh veneration process and difficult to control the shape of elements when comparing with the generation of nodes and elements concurrently. In this study, therefore, an algorithm it proposed to generate nodes and elements concurrently for various two-dimensional objects having multiple holes. Inner node generation is performed by choosing three consecutive boundary nodes and comparing them with other close boundary nodes. As soon as inner nodes are determined, element generation is conducted based on the comparison of the distances among the generated inner nodes, three consecutive boundary nodes and other close boundary nodes. the generated element nodes become new boundary nodes for further repeated process. The processes are repeated through out each region until three consecutive boundary nodes finally form a tirangular element.
Exchange of the Product Structure Data of STEP between CAD and PDM Systems
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 215~223
The product data exchange between heterogeneous CAB and PDM systems is a crucial issue for the integration of product development systems. STEP offers an efficient mechanism of product data exchange between heterogeneous systems. This paper introduces a UML-based mapping methodology for the product data models. The suggested mapping method has been applied to exchange the product structure data between CAD and PDM systems. Based on the STEP methods, we developed an interface module between a CAD system and a PDM system.
Development of Option Specification Management Function for Product Structure and Configuration
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 224~231
In order to satisfy customers'various needs in the market, manufacturing companies tend to add similar variants to an existing product model. This variety causes immense growth of product configuration and makes data management uncontrollable. In order to resolve this problem, we propose a method to efficiently represent the variants in a single schema of product structure and configuration and manage the product configuration. First of all, the product structure which adopts the concept of features and options is suggested. Second, the method to represent option specifications which restricts option configurations is proposed. Finally, the prototype module, which inspects if a product configuration violates the option specifications, is introduced
Web Interface for Distributed STEP Data using Metadata
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 232~241
Even though we have greater chances to accomplish successful collaborative design by utilizing recent proliferation of networks, current practices do not fully take advantage of the information infrastructure. There are so much data over the networks, but not enough knowledge about the data is available to users. The main objectives of the product data interface system proposed in this paper are to capture more knowledge on managing product data and to provide users effective search capability. We define the metadata model for product data defined in STEP AP 203 and manage the metadata from product data in a repository system. Because we utilize the standard formats such as STEP for product data and RDF for metadata, the proposed approach can be applied to various fields of industries independently on commercial products.
Sheet Offsetting Algorithms for Efficient Solid Modeling for Thin-Walled Parts
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 242~254
This paper describes an efficient solid modeling method for thin-walled plastic or sheet metal parts, based on the non-manifold offsetting operations. Since the previous methods for modeling and converting a sheet into a solid have adopted the boundary representations for solid object as their topological framework, it is difficult to represent the exact adjacency relationship between topological entities of a sheet model and a mixture of wireframe and sheet models that can appear in the meantime of modeling procedure, and it is hard to implement topological operations for sheet modeling and transformation of a sheet into a solid. To solve these problems, we introduce a non-manifold B-rep and propose a sheet conversion method based on a non-manifold offset algorithm. Because the non-manifold offset aigorithm based on mathematical definitions results in an offset solid with tubular and spherical thickness-faces we modify it to generate the ruled or planar thickness-faces that are mostly shown in actual plastic or sheet metal parts. In addition, in order to accelerate the Boolean operations used the offset algorithm, we also develope an efficient face-face intersection algorithm using topological adjacency information.
An Expert System for the Process Planning of the Elliptical Deep Drawing Transfer Die
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 255~262
A computer-aided process planning (CAPP) system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has not been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs an expert system of process planning for non-axisymmetric motor frame products with elliptical shape. The system developed consists of four modules. The first one is recognition of shape module to recognize the products. The second one is a 3-D modeling module to calculate surface area for non-axisymmetric products. The third one is a blank design module that creates an oval-shaped blank with the identical surface area. The forth one is a process planning module based on production rules that play the best important role in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. The constructed system using AutoLISP language under the AutoCAD environment is baled on the knowledge base system which is involved a lot of expert's technology. Results of this system will be provide effective aids to the designer and engineer in this field.
A Study on the Multidisciplinary Design Optimization Using Collaborative Optimization Approach
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 263~275
Multidisciplinary design optimization(MDO) can yield optimal design considering all the disciplinary requirements concurrently. A method to implement the collaborative optimization(CO) approach, one of the MDO methodologies, is developed using a pre-compiler “EzpreCompiler”, a design optimization library “EzOptimizer”, and a common object request broker architecture(CORBA) in distributed computing environment. The CO approach is applied to a mathematical example to show its applicability and equivalence to standard optimization(SO) formulation. In a realistic engineering problem such as optimal design of a two-member hub frame, optimal design of a speed reducer and initial design of a bulk carrier, the CO yields better results than the SO. Furthermore, the CO allows the distributed processing using the CORBA, which leads to reduction of overall computation time.
A Direct Expansion Algorithm for Transforming B-spline Curve into a Piecewise Polynomial Curve in a Power Form.
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 276~284
Usual practice of the transformation of a B-spline curve into a set of piecewise polynomial curves in a power form is done by either a knot refinement followed by basis conversions or applying a Taylor expansion on the B-spline curve for each knot span. Presented in this paper is a new algorithm, called a direct expansion algorithm, for the problem. The algorithm first locates the coefficients of all the linear terms that make up the basis functions in a knot span, and then the algorithm directly obtains the power form representation of basis functions by expanding the summation of products of appropriate linear terms. Then, a polynomial segment of a knot span can be easily obtained by the summation of products of the basis functions within the knot span with corresponding control points. Repeating this operation for each knot span, all of the polynomials of the B-spline curve can be transformed into a power form. The algorithm has been applied to both static and dynamic curves. It turns out that the proposed algorithm outperforms the existing algorithms for the conversion for both types of curves. Especially, the proposed algorithm shows significantly fast performance for the dynamic curves.
A Study on the Automatic Registration of Multiple Range Images Obtained by the 3D Scanner around the Object
Korean Journal of Computational Design and Engineering, volume 5, issue 3, 2000, Pages 285~292
A new method for the 3D automatic registration of the multiple range images has been developed for the 3D scanners(non-contact coordinates measurement systems). In the existing methods, the user usually has to input more than 3 pairs of corresponding points for the iterative registration process. The major difficulty of the existing systems lies in that the input corresponding points must be selected very carefully because the optimal searching process and the registration results mostly depend upon the accuracy of the selected points. In the proposed method, this kind of difficulty is greatly mitigated even though it needs only 2 pairs of the corresponding input points. Several registration examples on the 3D measured data have been presented and discussed with the introduction to the proposed algorithm.