http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
정승원(S. W. Jeong),이성원(S. W. Lee),정완진(W. J. Chung),전만수(M. S. Joun) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
In this paper, a reaction-to-die penetration scheme is presented to deal with the force prescribed dies such as the binders in sheet forming or plate forging, the guide plate and counter punch in fine blanking and the spring attached die and back pressing die in forging. A holding force die is employed to define the region where the force is exerted. In the scheme, the holding force is exerted in the material surface in terms of traction which is calculated by a function of penetration depth of material into the die. The scheme is applied to a fine blanking process using a rigid-plastic finite element method. The traction can be regarded as a kind of reaction force to protect the penetration of material into the holding force die. The predictions are discussed to reveal the effect of the reaction-to-die penetration scheme.
비선형 변형경로를 고려한 판재성형 한계곡선에 대한 수치적 비교 연구
김진학(J. H. Kim),임재혁(J. H. Lim),조인영(I. Y. Cho),양진아(J. A. Yang),정완진(W. J. Chung) 한국소성가공학회 2013 금형가공 심포지엄 Vol.2013 No.9
For the nonlinear strain path, traditional strain based FLD, linear FLD, reveals inaccuracies in the formability prediction. On the other hand, forming limit stress diagram, FLSD, shows superiority in formability prediction for nonlinear strain path. Nevertheless, the use of FLSD is very limited because of low sensitivity near forming limit and difficulty of understanding. Recently, effective plastic strain based FLD, EPS FLD, was proposed and supposed to get wider acceptance in the near future. In the present study, linear FLD and EPS FLD were compared for simulation of square cup deep drawing. In making of EPS FLD, numerical oscillations in deformation from simulation yield impractical oscillatory deformation paths. In order to obtain continuous and non-oscillatory deformation paths, a linear regression technique was utilized. In the comparison, EPS FLD shows different formability from linear FLD numerically. Experimental verification is strongly required to assess the suitability of EPS FLD definitely.