http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
AA5083-H18판재의 마찰 교반 점 용접 공정에 대한 전산 해석
김돈건(Dongun Kim),Badarinarayan Harsha,유일(Ill Ryu),김지훈(Ji Hoon Kim),김종민(Chongmin Kim),Okamoto Kazutaka,Wagoner R. H.,정관수(Kwansoo Chung) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.5
Thermo-mechanical simulation of the Friction Stir Spot Welding (FSSW) processes was performed for the AA5083-H18 sheets, utilizing commercial Finite Element Method (FEM) and Finite Volume Method (FVM) which are based on Lagrangian and Eulerian formulations, respectively. The Lagrangian explicit dynamic FEM code, PAM-RASH, and the Eulerian Computational Fluid Dynamics (CFD) FVM code, STAR-CD, were utilize to understand the effect of pin geometry on weld strength and material flow under the unsteady state condition Using FVM code, material flow pattern near the tool boundary was analyzed to explain the weld strength difference between the weld by cylindrical pin and the weld by triangular pin, while the frictional energy concept using the FEM code had limitation to explain the weld strength difference.
단면변화 롤포밍 기술(MD-RF)을 활용한 시험부품 개발
차명환(Myunghwan Cha),김돈건(Dongun Kim) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5
Roll forming is a productive and cost effective forming method. Due to the increase of application of high strength steel in automobile, the importance of roll forming, which is able to form UHSS, is rising. But roll forming has a limitation that can form only uniform sectional product. MD-RF is forming method developed to overcome this limitation which can manufacture variable sectional product by linear and rotational movement of roll sets. In this research, two object part of width variation and wall height variation was manufactured to verify the feasibility of MD-RF technology and performance of the test equipment.
류한선,김지훈,이명규,김돈건,이형림,정관수,윤재륜,강태진,Ryou Hansun,Kim Ji Hoon,Lee Myoung-Gyu,Kim Dongun,Lee Hyung Rim,Chung Kwangsoo,Youn Jae Ryoun,Kang Tae Jin The Korean Fiber Society 2005 한국섬유공학회지 Vol.42 No.5
In order to describe the mechanical behavior of highly anisotropic and asymmetric materials such as fiber reinforced composites, the elastic-plastic constitutive equations were used based on the recently developed yield criterion and hardening laws. As for the yield criterion, modified Drucker-Prager yield surface was used to represent the orthotropic and bi-modular (asymmetric) properties of composite materials, while the anisotropic evolution of back-stress was used to account for the hardening behavior. Experimental procedures to obtain the material parameters of the hardening laws and yield surface are presented for 3D braided glass fiber reinforced composites. For verification purposes, finite element simulation results based on the proposed constitutive laws have been compared with measurements for the three point bending tests.
열간프레스성형에서의 변형 측정장치 개발 및 기계적 거동의 물성화
유동훈(Donghoon Yoo),석동윤(Dong-Yoon Seok),김돈건(Dongun Kim),안강환(Kanghwan Ahn),손현성(Hyun-Sung Son),김교성(Gyo-Sung Kim),정관수(Kwansoo Chung) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.10
As a way to improve the safety of automotive and to reduce the weight of vehicles, new forming technologies and advanced materials are in high demand in the automotive industry. However, the advanced strength steel has inferior formability and large springback. In order to overcome such drawbacks, the hot press forming process (HPF) has been being applied for forming of automotive sheet parts. In this work, new equipment was suggested to measure unlimited displacement range compared to previous one which was able to measure only up to 10mm displacement range. The external extensometer connected with grips by wire was applied to equipment so that total strain range was measured up to failure also in high temperature. And the finite element analysis was conducted to characterize the mechanical properties of the HPF steel. Finally, the flow curves were represented by utilizing the Johnson-Cook type equation both in uniform and post-uniform deformation regions.