• Transactions of the Korean Society of Automotive Engineers
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• 제15권1호
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• pp.146-153
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• 2007

Weight reduction for automobile components has been sought to achieve fuel efficiency and energy conservation. There are two approaches in reducing their weights. One is by using material lighter than steel, and the other is by redesigning their structures. The latter has been performed by adopting hydroforming, tailor weled blank, optimization, etc. In this research, the kriging approximation method and simulated annealing algorithm are applied to the design of a front door made by TWB (Tailor Welded Blank) technology. The design variables are set up as the thicknesses of parts and the positions of parting lines. A thickness set considered as a design variable of each part is not arbitrarily determined but selected from standard products, so it is a discrete set. This research presents the discrete and continuous structural optimization method for an automotive door design.

• Laser Solutions
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• 제18권2호
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• pp.5-10
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• 2015

A tailor welded blank (TWB) is a welded blank comprised of two or more sheets with different properties - thickness, strengths or formabilities. TWBs are applied to the body panels to reduce weight and cost of the part. In this research, ultra high strength steel and high ductility steel were joined and laser tailor welded blanks were implemented. Yb:YAG laser welding tests were conducted with various welding conditions, and mechanical and geometrical characteristics of weldments were evaluated.

• International Journal of High-Rise Buildings
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• 제9권3호
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• pp.261-271
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• 2020

The 2020 National Building Code of Canada (NBC) and the 2021 International Building Code (IBC) both include Tall Wood Buildings (TWB) and are hailed as documents responsible for the proliferation of Mass Timber construction. Mass Timber construction is critical to reducing the carbon footprint of the construction industry; a sector acknowledged as being one of the greatest contributors of global annual CO₂ emissions. Origine, a 13-storey multi-residential building erected in 2017 in a previously unsuitable site, is currently the tallest all-wood building in North America. This article describes the challenges overcome by the designers and client as they engaged with code officials, building authorities, and fire-service representatives to demonstrate the life-safety performance of this innovative building. It also traces the development of the "Guide for Mass Timber Buildings of up to 12 Storeys" published in Quebec and how it has enabled other significant Tall Wood projects across North America.

• 연구논문집
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• 통권32호
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• pp.85-94
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• 2002

Even in the world wide automobile companies where a few simple modules are put into practical use, the front subframe modules of which performances of durability, NVH and crash are significantly important are under planing. In this study, design technology for the automobile front subframe module, which consists of an engine, a transmission and steering parts, structural components (frame, upper arm, lower arm and brake etc.) and rubber components(engine mount, axle mount and rubber disc etc.), was developed. A FEM-based analytical approach was used to evaluate the multiaxial high cycle fatigue damage of the front subframe module. Strain-life fatigue database system and expert system for fatigue properties of welded materials were developed. Stiffness values of the various rubber bushes mounted on the front subframe were evaluated by experimental method and FEM. TWB(Tailor Welded Blank) technology was applied to forming the cross member of the front subframe. Performance evaluations in relation to NVH and crash were conducted by using CAE technologies.

• Transactions of Materials Processing
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• 제18권6호
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• pp.488-493
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• 2009

The very big springback of advanced high strength steel(AHSS) sheets invokes undesired shape defects, which can be generally eliminated by die correction or process parameter control. The springback reduction by controlling the forming process parameters is easy for the application, but limited for the bulky achievement. In this study, the effective die correction method, which obtains the modification of tool shape from the relationship between die design variable and springback, is introduced and is applied to the TWB tool of automotive side rail to show the validity and usefulness. Among the die correction trials repeatedly performed, the first trial is carried out by correcting the tool shape to the opposite direction to the springbacks of several tool sections. Next trials are done by extrapolating the springbacks of among the original tool uncorrected and the tools corrected negative amounts of the springback and by finding tool shapes without springbacks. After the angle of side wall and radius of curvature of horizontal bottom floor are chosen as design variables in the tool design of side rail, the tool shape is corrected 3 times. The accuracy of final shape within the assembly limit of 1mm and the springback reduction of 75.8% compared to the uncorrected tool are achieved.

• Transactions of Materials Processing
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• 제13권8호
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• pp.678-688
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• 2004

The U-draw bending operation is known as a representative test method for springback evaluation of sheet metals since the sheet in U-draw bending operation undergoes stretching, bending and unbending deformations occurred at the stamping process. In this study, a simplified approach was proposed for predicting springback and side-wall curls of tailor-welded blank in U-draw bending operations, using moment-curvature relationships derived for sheets undergoing stretching, bending and unbending deformation. Two different welded strips were adopted to compare the effects of weld-line locations on the springback. One (type A) was welded along the centerline of the strip-width and the other (type B) was welded along the centerline of the strip-length. To investigate the effect of different thickness combination on the springback, the tailor-welded strips were joined by the laser welding process and consisted of three types of thickness combinations of sheets, SCP1 0.8t ＊ SCP1 1.2t, SCP1 0.8t ＊ SCP1 1.6t and SCP1 0.8t ＊ TRIP 1.0t. Some calculated results by the simplified formula were compared with experimental results.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제14권3호
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• pp.277-286
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• 2001

Among the ULSAB methods for the lightweight automobile body, Tailor Welded Blank(TWB) is adopted and the design process is developed for the existing component. Topology optimization conducted to find the distribution of the variable thickness. The number of parts and the welding lines are determined from it. In the detail design, size optimization is carried out to find the optimum thickness of each part and then, the final parting lines are tuned by shape optimization. A commercial optimization software GENESIS is utilized for the optimization processes.

• The Safety technology
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• 제176호
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• pp.18-19
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• 2012

우리나라 해양경영의 요충지인 광양만. 이곳에는 광양제철소라는 우리나라의 대표적인 제철소가 자리 잡고 있다. 광양국가산업단지의 중심업체인 광양제철소는 자동차 강판 및 에너지용 강재 전문 제철소로 직원 1만 7천여 명이 1년 365일 밤낮없이 용광로의 불꽃을 지키고 있다. 광양제철소는 (주)포스코의 전신인 포항종합제철이 포항제철소에 이어 건설한 제2제철소다. 1985년 연간 270만 톤의 조강능력을 갖춘 1기 설비 건설에 착공하여 1992년 종합 준공하였으며, 그 이후 1999년 3월에는 5고로를 준공했다. 그 외에 2005년 LNG 터미널 준공 2006년 TWB 공장 준공, 2008년 자동차강반기술센터 준공 등을 거치면서, 지난해 세계 1위의 후판 생산업체로 도약했다. 광양제철소는 단일 제철소로는 세계 최대 규모를 자랑한다. 600만 평의 부지에 조강 생산량은 연간 1,950만 톤(2010년 기준)에 달한다. 여기에 만족하지 않고 올해에는 2,300만 톤의 목표를 달성해, 세계적인 제철소로서의 입지를 확고히 다져나간다는 계획을 세우고 있다. 이처럼 무한한 철강의 꿈을 인류와 함께 실현해나가고 있는 광양제출은 산업안전 분야에서도 명성이 높다. 세계적 기업답게 선진 안전관리가 펼쳐지고 있는 것. 그 중심에는 제철소 현장의 전반적인 안전을 담당하는 김성철 안전팀 파트장이 있다.

• Journal of the Korean Society of Mechanical Technology
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• 제13권1호
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• pp.105-112
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• 2011

Increasing needs for light weight and high safety in modern automobiles induced the wide application of high strength steels in automotive body structures- The main difficulty in the forming of sheet metal parts with high strength steel is the large amount of springback including sidewall curl and twist in channel shaped member parts- Among these shape defects, twist occurs frequently and requires numerous reworks on the dies to compensate the shape deviation- But until now, it seems to be no effective method to reduce the twist in the forming processes- In this study, a new forming process to reduce the twist deformation during the forming of automotive structural member was suggested- This method consists of forming and restriking of embosses on the sidewall around the stretch flanging area of the part- and was applied in the forming process design of an automotive front side inner member with high strength steel- To evaluate the effectiveness of the method, springback analysis using $Pamstampa^{tm}$ was done- Through the analysis results, the suggested method was proven to be effective in twist reduction of channel shaped parts with stretch flanging area.

• Transactions of the Korean Society of Automotive Engineers
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• 제14권6호
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• pp.112-119
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• 2006

This paper is concerned with the light-weight design of a center-pillar assembly for the high-speed side impact of vehicle using advanced high strength steels(AHSS). Steel industries continuously promote the ULSAB-AVC project for applying AHSS to structural parts as an alternative way to improve the crashworthiness and the fuel efficiency because it has the superior strength compared to the conventional steel. In order to simulate deformation behavior of the center-pillar assembly, a simplified center-pillar model is developed and parts of that are subdivided employing tailor-welded blanks(TWB) in order to control the deformation shape of the center-pillar assembly. The thickness of each part which constitutes the simplified model is selected as a design parameter. Factorial design is carried out aiming at the application and configuration of AHSS to simplified side-impact analysis because it needs tremendous computing time to consider all combinations of parts. In optimization of the center-pillar, S-shaped deformation is targeted to guarantee the reduction of the injury level of a driver dummy in the crash test. The objective function is constructed so as to minimize the weight and lead to S-shape deformation mode. Optimization also includes the weight reduction comparing with the case using conventional steels. The result shows that the AHSS can be utilized effectively for minimization of the vehicle weight and induction of S-shaped deformation.