• Journal of Powder Materials
• /
• v.17 no.6
• /
• pp.435-442
• /
• 2010

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 1999.11a
• /
• pp.21-24
• /
• 1999

• Structural Engineering and Mechanics
• /
• v.7 no.6
• /
• pp.589-599
• /
• 1999

This paper presents the development and applications of the software package JIFEX, a new finite element system which can be used for structural analysis and optimum design by the modern computer hardware and software technologies such as MS Windows95/NT and Pentium PC platforms. The complete system of JIFEX is programmed with $C/C^{++}$ language to make full use of advanced facilities of MS Windows95/NT. In the system, the finite element data pre-processing, based on the most popular CAD package AutoCAD (R13, R14), has been implemented, so that the finite element modeling could be integrated with geometric modeling of CAD. The system not only has interactive graphics facility for data post-processing, but also realizes the real-time computing visualization by means of the Dynamic Data Exchange (DDE) technique. Running on the Pentium computers, JIFEX can solve large-scale finite element analysis problems such as the ones with more than 60000 nodes in the finite element model.

• Transactions of Materials Processing
• /
• v.21 no.7
• /
• pp.412-419
• /
• 2012

The ingot-breakdown scheme of a tower flange material (low-alloy steel) for offshore wind turbine was investigated using finite element (FE) simulations and experimental analyses. Based on compression test results of the low-alloy steel, a deformation processing map was generated using the superposition approach between the dynamic materials model (DMM) and Ziegler's instability criterion. The deformation processing map allowed determination of the optimum process conditions for the tower flange material. Within the FE simulations of the ingot breakdown process, the Cockcroft-Latham criterion, which considers ductile fracture, was used to predict the possibility of forming defects during the hot working process. In general, the critical value for the ductile fracture of steel is 0.74. During the ingot-breakdown under optimum process conditions, the actual tower flange forgings exhibited a relatively uniform shape without any forming defects.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.993-998
• /
• 2002

Ultra precision processing technology is the field which is seriously protected its technology by advanced nations. Because of this reason, this technology is very difficult to supply for domestic companies, also domestic companies are revealed the limit of technology development by itself. And then, those are depend on the technology development of advanced nation, domestic companies are not conquer application step with already developed parts. Of course, some cases of its research are succeed. those are included element technology, system technology and so on, for development of ultra precision processing system. To conquer technology holding ultra precision processing accuracy of no level, active research are needed. In this paper, stability of ultra precision cutting unit is analyzed, this unit is the kernel unit in ultra precision processing machine. According to alteration of shape and material about hinge, stability investigation is performed Through this stability investigation, trial and error is reduced in design and manufacture, at the same time, we are accumulated foundation data for un it control.

• Membrane Journal
• /
• v.16 no.3
• /
• pp.213-220
• /
• 2006

Microfiltration and Nanofiltration membrane were prepared and properties of the membrane system were studied for the application of desaltingfrefiningiconcentrating process of dye production. The membrane system improved the quality of dye produce and productivity was enhanced due to reduction of processing steps and material cost. Membrane and pressure type membrane element in various dye concentration for using desaltingirefiningiconcentrating of dye processing were investigated.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.1
• /
• pp.15-21
• /
• 2017

In this paper, we present a solution to the problems caused by using only text - based information as an index element when a commercialized missing person indexing system indexes missing persons registered in the database. The existing system could not be used for the missing persons inquiry because it could not formalize the image of the missing person registered together when registering the missing person. To solve these problems, we propose a method to extract the similarity of images by using OpenCV image processing and TensorFlow deep - running image processing, and to process images of missing persons to process them into meaningful information. In order to verify the indexing method used in this paper, we constructed a Web server that operates to provide the information that is most likely to be needed to users first, using the image provided in the non - regular environment of the same subject as the search element.

• Journal of The Korean Association For Science Education
• /
• v.38 no.3
• /
• pp.441-449
• /
• 2018

The knowledge and information processing competence is one of the essential competencies in an information-oriented society which is highly related to science education. The purpose of this study is to investigate middle school students' difficulties in science inquiry activity in view of the knowledge and information processing competence. Collection, processing, and application of information are extracted as common elements of the knowledge and information processing competence through literature search. Data were obtained from eight students of a middle school in Seoul for five months and were analyzed based on constant comparative method to extract students' difficulties. As a result, the element of information collection is observed through science inquiry and the element of information processing is observed in hypothesis setting step, inquiry result analysis step, and inquiry result sharing step. The element of information application is observed in the creation of posters for sharing and inquiry reports. Difficulties in information collection were found in lack of confidence in information gathering, systematic search strategy, and information reliability. Difficulties in information processing appeared in the inexperience of analysis program use, information transformation, and interpretation of linkage information. Difficulties in information application were caused by the lack of effective organization and effective expression of information. In this study, it is meaningful to provide a clue as to how the knowledge and information processing competence can be established in science education.

• Transactions of Materials Processing
• /
• v.21 no.7
• /
• pp.447-452
• /
• 2012

This paper is concerned with forming of Al-Zn-Mg-Sc aluminum alloy bolts, focusing on the effects of heat treatment and age-hardening on the formability and ductile damage evolution. Both experimental and finite element studies were performed. From the experiments, it is observed that the heat treatment or the normalization of Al-Zn-Mg-Sc aluminum alloy increases its formability dramatically resulting in successful bolt forming, while the effects of age-hardening at room temperature on the stress-strain relationship and formability are not very critical. Deformation characteristics such as distribution of effective stress and strain, material flow, and ductile damage evolution during bolt forming are examined using a commercial finite element package, Deform-2D. It should be noted that the extrusion load predicted by the finite element method matches well the experiment results. The finite element predictions on the deformation characteristics support the experimental observations such as fracture of bolt head flange, material flow, and distribution of hardness.

• Transactions of Materials Processing
• /
• v.11 no.1
• /
• pp.75-83
• /
• 2002

Recently, the hydroforming process is widely applied to the automotive industry and rapidly spreaded to other industries. In this paper, An implicit finite element formulation for simulating axisymmetric tube hydroforming processes is performed. In order to describe normal anisotropy of the tube, Hill's non-quadratic yield function is employed. The frictional contact between die and tube and the frictionless contact between tube and fluid are considered using the mesh-normal vectors computed from the finite element mesh of the tube. The complete set of the governing relations comprising equilibrium and interfacial equations is linearized for Newton-Raphson procedure. In order to verify the validity of the developed finite element formulation, the axisymmetric tube bulge test is simulated and the simulation results are compared with experimental measurements. In a simulation of stepped circular tube hydroforming processes, an optimal hydraulic pressure curve is pursued by considering simultaneously internal pressures and axial forces.