• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.693-699
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• 2013

Environmental issues are attracting increasing interest worldwide, and accordingly, environmental regulations for vehicles are being made more stringent. As a result, the car industry is conducting studies focusing on fuel efficiency and lightweight vehicles. To manufacture lightweight vehicles, existing steel parts are replaced by composite materials and lightweight metals. In this study, the fatigue life of a new material for manufacturing lightweight car door hinges was predicted using a finite-element analysis program. The existing steel material was replaced by carbon-fiber-reinforced plastic (CFRP) and aluminum alloy 6061, and the test results were analyzed. The maximum stress decreased by approximately three times, whereas the fatigue life and safety factor increased. When only CFRP was used, its allowable stress, safety factor, and fatigue life were excellent, but the sagging of the product exceeded the allowable value, which posed a limitation in use. Therefore, it seems desirable to use an appropriate combination of steel, AA6061, and CFRP for this product.

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.1
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• pp.23-28
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• 2023

Carbon materials are widely used in many areas of our lives. A fiber having a carbon content of 90% or more obtained by heating an organic fiber precursor is referred to as a "carbon fiber". Carbon fibers are currently used in the medical market to manufacture radiation transmission device parts, artificial joints, and medical aids, as many developments have been made to utilize carbon fibers' characteristics such as light weight, radiation permeability, biocompatibility, high strength, high heat resistance, thermal conductivity, and electrical conductivity. In order to maintain body temperature and increase immunity in long-lasting nuclear medical examination and treatment through the idea of convergence of carbon materials and radiation technology, the quality of medical services can be improved by utilizing carbon materials. We should be aware of the domestic carbon-based medical device industry and make efforts to contribute to the development of medical devices. As a radiation expert, we should try to use our skills and experience to find items that can be fused with medical devices to develop various nuclear medical examination fields and radiographic examination fields that can be widely applied. We should actively engage in future technology development and carbon material research to strengthen the global competitiveness of the domestic medical device industry and improve the quality of medical services.

• Elastomers and Composites
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• v.51 no.4
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• pp.308-316
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• 2016

The rubber materials are widely used in automobile industry due to their capability of a large amount of elastic deformation under a force. Current trend of design process requires prediction of functional properties of parts at early stage. The behavior of rubber material can be modeled using strain energy density function. In this study, five different strain energy density functions - Neo-Hookean model, Reduced Polynomial $2^{nd}$ model, Ogden $3^{rd}$ model, Arruda Boyce model and Van der Waals model - were used to estimate the behavior of carbon black added natural rubber under uniaxial load. Two kinds of tests - uniaxial tension test and biaxial tension test - were performed and used to correlate the coefficients of the strain energy density function. Numerical simulations were carried out using finite element analysis and compared with experimental results. Simulation revealed that Ogden $3^{rd}$ model predicted the behavior of carbon added natural rubber under uniaxial load regardless of experimental data selection for coefficient correlation. However, Reduced Polynomial $2^{nd}$, Ogden $3^{rd}$, and Van der Waals with uniaxial tension test and biaxial tension test data selected for coefficient correlation showed close estimation of behavior of biaxial tension test. Reduced Polynomial $2^{nd}$ model predicted the behavior of biaxial tension test most closely.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.41-46
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• 2017

Productivity improvement and cost reduction in the aircraft industry have become major industrial objectives, and improving productivity by reducing machining time has become a key focus. When numerical cutting code is created by CAM software, such as CATIA or UG-NX, it is impossible to control machining feed speed using cutting force changes depending on the machining tool path. However, machining an aircraft engine part from difficult material, such as Inconel 718, takes a long time, and tool chipping or breakage often occurs from forcing the machining path too quickly. This study investigated and verified the reliability of the AdvantEdge production module (PM)using cutting power tests. In particular, diffuser and diffuser case parts were considered, comparing cutting power and machining time using AdvantEdge PM and CATIA.

• Journal of Korean Society for Quality Management
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• v.28 no.4
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• pp.204-222
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• 2000

Supply Chain Management is a process-oriented concept, integrated approach to procuring, producing, and delivering products and services to customers. Supply Chain Management covers the management of material, information, and funds flows. A strategic supply chain management produces for value maker and the ultimate customer. One aim of this paper is to determine the effect of contract parameters on the quality of the end product of the supplier-producer chain. The supply chain management is viewed as a single entity rather fragmented. This research constructed model the relationship of supply chain management to quality management. The questionnaire were tested with survey of supplier's employee and the result were analyzed using SEM(Structural Equation Model). As a result, Quality performance positively depends on the communication, coordination, and process management between the supplier and the producer.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.470-477
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• 2017

Ceramic processing to fabricate 3D complex ceramic structures is crucial for structural, energy, environmental, and biomedical applications. A unique process is ceramic stereolithography, which builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This approach directly writes layers in liquid ceramic suspension and allows one to fabricate ceramic parts and products having more accurate, complex geometries and smooth surfaces. In this paper, both UV curable materials and processes are presented. We focus on the basic material principles associated with free radical polymerization and rheological behavior, cure depth and broadening of cured lines, scattering at ceramic interface and their corresponding simulation. The immediate potentials for ceramic AM to change industry fabrication are also highlighted.

• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.92-97
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• 2009

In order to export aircraft components or substructures, it is necessary to get a certification from the main company for the components or an airworthiness certification from the FAA. In Korea, those processes are performed by a small number of private companies for aircraft components. However, airworthiness certification has never been done in the company. To export an assembled aircraft, whether small or large, it is obligatory to get a certification for the aircraft being exported. Currently, the Korean government is trying to get BASA agreement in a few years. For a mid-size company, it is easier to get the NADCAP audit process for the supply of aircraft components to the main company. In this paper, the overall process of aircraft certification is discussed and airworthiness certification is treated for export aircraft. Moreover, the NADCAP audit process is described in detail by introducing example parts made of composite material. This detailed process would be very helpful to a small or mid-size company that wants to develop and deliver aircraft components to foreign companies.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.511-520
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• 2010

In general, spot welding is used at no welding rod or flux for the process, low welding point temperature compared to arc welding, short heating time, less damage to the parent material, and low deformation and residual stress, relatively. Also, because of the pressurization effect, better mechanical qualities of the welding parts are obtained. Therefore, in various fields of industry its rapid operation speed can make mass production possible such as motor industry. In FEM analysis for the spot welding process, it is effective to use simple modeling rather than complicated one because of its numerous number of spots and reduction of analysis time. Therefore, this study provides with not only simplification of modeling analysis by using beam component composition of structure without re-compositing the spot welding point mesh but also modeling analysis of which property of fracture strength is reflected. In addition complete spot welding model is examined at rectangular post shape (hat shape) by impact test, compared the results, and verified its validity. As a result, it is possible to optimize the welding position and to recognize the strength of structure and the proposed equal distance model shows the effect of welding point reduction and improvement of stiffness.

• Smart Structures and Systems
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• v.20 no.1
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• pp.1-10
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• 2017

Ionic Polymer Metal Composite (IPMC) is an electroactive polymer (EAP) and a promising candidate actuator for various potential applications mainly due to its flexible, low voltage/power requirements, small and compact design, and lack of moving parts. Although widely used in industry, this material requires accurate numerical models and knowledge of optimal control methods. This paper presents State-Dependent Riccati Equation (SDRE) approach as one of rapidly emerging methodologies for designing nonlinear controllers. Additionally, the present paper describes a novel method of Multi HGO Observer design. In the proposed design, the calculated position of the IPMC strip accurately tracks the target position, which is illustrated by the experiments. Numerical results and comparison with experimental data are presented and the effectiveness of the proposed control strategy is verified in experiments.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.869-877
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• 2011

In order to manufacture precision parts which are used for IT and BT Industry by machining, users need higher speed & precision machining center. So, for development of this kind of machine, we designed gantry type machining center which is piling of 3 axes on one moving body and the 2-axis rotary table is fixed on the base. It is applied linear motor that is instead of ball-screw and servo-motor combination and 50,000 rpm high-speed spindle. Composite material structure called mineral casting or resin concrete is applied also. This paper presents design technology and evaluated results of high speed and precision machining center.