• Transactions of Materials Processing
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• v.16 no.1 s.91
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• pp.67-74
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• 2007

This study is aimed to find out the optimal forming conditions by comparing and analyzing material flow, deformation pattern, and a forming load through rigid-plastic FEM for a flange using pipe. Flanges are widely used for various purposes as connectors of industrial steel pipes which are manufactured by drawing process. The forming feature of flange was reviewed through both heading process and radial extrusion process in a cold working condition. As a result of simulation, the shape of flange can not be made by heading process, but made by radial extrusion process. The effects of design factors, such as gap-height, die-comer radius, and frictional factors on maximum forming load and deformation pattern are investigated for radial extrusion process.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.331-335
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• 2009

A novel multi-staged waste pyrolysis & gasification system of pilot scale (~1 ton/day) is designed and constructed in Korea Institute of Industrial Technology. The pyrolysis & gasification system is composed of pyrolysis & gasification system, syngas reformer, syngas cleaning system, gas engine power generation system and co-combustion system. For each unit process, experimental approaches have been conducted to find optimal design and operating conditions. As a result, We can produce syngas with a calorific value of ~4000 kcal/$Nm^3$ and cold gas efficiency of the system is more than 55 % in case of waste plastic and oxygen as a gasifying agent.

• Computers and Concrete
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• v.30 no.6
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• pp.393-407
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• 2022

Due to the enormous cement content, pozzolanic materials, and the use of different aggregates, sustainable controlled low-strength material (CLSM) has a higher material cost than conventional concrete and sustainable construction issues. However, by selecting appropriate materials and formulations, as well as cement and aggregate content, whitethorn costs can be reduced while having a positive environmental impact. This research explores the desire to optimize plastic properties and 28-day unconfined compressive strength (UCS) of CLSM containing powder content from unprocessed-fly ash (u-FA) and recycled fine aggregate (RFA). The mixtures' input parameters consist of water-to-cementitious material ratio (W/CM), fly ash-to-cementitious materials (FA/CM), and paste volume percentage (PV%), while flowability, bleeding, segregation index, and 28-day UCS were the desired responses. The central composite design (CCD) notion was used to produce twenty CLSM mixes and was experimentally validated using MATLAB by an Artificial Neural Network (ANN). Variance analysis (ANOVA) was used for the determination of statistical models. Results revealed that the plastic properties of CLSM improve with the FA/CM rise when the strength declines for 28 days-with an increase in FA/CM, the diameter of the flowability and bleeding decreased. Meanwhile, the u-FA's rise strengthens the CLSM's segregation resistance and raises its strength over 28 days. Using calcareous powder as a substitute for cement has a detrimental effect on bleeding, and 28-day UCS increases segregation resistance. The response surface method (RSM) can establish high correlations between responses and the constituent materials of sustainable CLSM, and the optimal values of variables can be measured to achieve the desired response properties.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.185-191
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• 2013

This paper presents a new method for roller design of IRB(isolation roller bearing) seismic isolation device using experimental evaluation. Three layered plate is adopted for the IRB in which the upper plate is placed on x direction and the lower plate is placed on y direction. The rollers placed in each plate make a plate movement. The roller is then optimally designed using variable geometric conditions. Stress distribution depends on the diameter and length of the roller and hence this is used for the determination of optimal geometry of the roller. In the experimental evaluation, it is observed that stress concentration at the end sides of roller is decreased and geometric coefficients depend on crowning dimension. In addition, in order to determine optimal design parameters of the roller the plastic deformation and friction are experimentally identified.

• Transactions of Materials Processing
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• v.22 no.1
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• pp.36-41
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• 2013

The present study examines the micro-pattern replication on a plastic film using ultrasonic imprinting. Ultrasonic imprinting uses ultrasonic waves to generate repetitive microscale deformation in the polymer film. The resulting deformation heat on the surface of the film causes the surface region to soften sufficiently so that a replication of the micro-pattern can be obtained. To successfully replicate the micro-pattern on a large area of polymer film, a high replication ratio is needed as well as good uniformity over the entire region. In this study, a horn design is investigated by finite element analysis and is optimized through a response surface analysis. In the ultrasonic imprinting experiments, the response surface method was also used to determine the optimal processing conditions for better replication characteristics.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.199-206
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• 1997

The inner pulley is an automobile component used as air conditioner clutch assembly. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and outer one, and to make uniform the hardness distribution in the forged product. In industry, the design of forging processes is performed based on experience-oriented technology, that is, designers experience and expensive trial and error. Using the rigid-plastic finite element simulations. we design the optimal process conditions, which has a preforming operation. Also the final product configuration of forging has to be designed again in view of metal flow involved in the operation, derived from the finite element simulations. The forged pulley is investigated by checking the hardness distribution and it is noted that distribution has improved to be even and high enough for industrial application.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1362-1365
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• 2003

On this study. we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized buckling strength of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result optimization achievement repeatedly using statistical orthogonal array of experimental design.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.62-70
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• 1995

The inner pulley is automobile component used as airconditioner clutch assembly. in cold forging of the inner pulley . the design conditions are the same between inner length and outer length, the uniform hardness and the no shape change in inner fillet radius due toa piercing. In industries, the design of forging processes is performed based on an experience-oriented technology, that is, designer's experiences and expensive trial and error. Using the rigid -plastic finite element simulation, we propose the optimal process conditons and design of preform or redesign of final product shape without defects prodicted by metal flow, distribution fo strain, forging load during forging processes form initial workpiece to final product.

• Transactions of Materials Processing
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• v.6 no.4
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• pp.329-337
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• 1997

Forging of an inner pulley for compressor clutch assembly of car air conditioner is investigated in this study. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and the outer one, and to make uniform the hardness distribution in the forged product. Using the rigid-plastic finite element simulation. we design the optimal process conditions, which has a performing operation. Also the final product configuration of forging has to be designed again in view of the metal flow involved in the operation, derived from the finite element simulations. The forged pulley is investigated by checking the hardness distribution and it is noted that the distribution has improved to be even and high enough for industrial application.

• Computers and Concrete
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• v.13 no.2
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• pp.235-253
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• 2014

The theoretical basis and the main results of a design procedure, which attempts to provide the optimal layout of ordinary reinforcement in prestressed concrete beams, subjected to bending moment and shear force are presented. The difficulties encountered in simulating the actual behaviour of prestressed concrete beam in presence of coupled forces bending moment - shear force are discussed; particular emphasis is put on plastic models and stress fields approaches. A unified model for reinforced and prestressed concrete beams under axial force - bending moment - shear force interaction is provided. This analytical model is validated against both experimental results collected in literature and nonlinear numerical analyses. Finally, for illustrating the applicability of the proposed procedure, an example of design for a full-scale prestressed concrete beam is shown.