http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
구병춘(B. C. Goo),정현승(H. S. Jung) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
Aluminum alloy composites with SiC particles are useful for weight reduction of mechanical components. But they are expensive and it is difficult to make complex components. If we found out a reliable method to join aluminum alloys and Al/SiC composites, we could make complex mechanical parts at a low price. In this study A356 aluminum alloy and A356/SiC 20 vol.% composite were chosen as dissimilar materials. To join two different materials by casting, first, A356 blocks were cast and cylindrical holes with conical end were drilled in the blocks. A mold with a cylindrical hole was placed on an A356 cast block. Molten A356/SiC at about 750℃ was poured into the mold. Before pouring molten A356/SiC, A356 blocks were heated and kept at 550℃. Using the specimens tensile strength tests were carried out. As tensile forces increased, some composite bars were pulled out from the A395 blocks and others fractured near the border. Tensile strengths depended on the surface conditions of the cast-bonded joints.
철도 차량용 티어링 튜브의 충돌 에너지 흡수 능력 예측 기법
고윤기(Y. K. Ko),안광현(K. H. Ahn),허훈(H. Huh),최원목(W. M. Choi),정현승(H. S. Jung),권태수(T. S. Kwon) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.5
This paper deals with the numerical prediction of energy absorbing capacity of a tearing tube, which can absorb the crash energy through expanding and axial splitting process. It is important to consider the dynamic material behavior and fracture characteristics of tube material in order to simulate accurately the deformation behavior of tearing tube. Therefore, uniaxial tensile tests are performed in order to obtain the flow stress curve and fracture strain of tube material according to strain rate. Quasi-static tensile tests were carried out in the range of strain rate from 0.001/sec to 0.01/sec using the static tensile testing machine. Dynamic tensile tests were conducted at the strain rate ranged from 0.1/sec to 300/sec using the high speed material testing machine. These dynamic material properties are applied to finite element analysis through user material subroutine of ABAQUS/Explicit. Especially, ductile fracture criterion is applied in order to describe the fracture characteristics of tube material during axial splitting process. Dynamic tearing cases are simulated and the reliability of the numerical results is verified by comparing with the experimental result in dynamic tearing test. The simulated results predict accurately the onset of fracture in axial splitting process and the energy absorption capacity has a good agreement with experimental result.