저자명 최태훈 
년도 1999 
Sheet metal forming process is widely used in industries due to its various advantages. With the increasing need from industries, there have been remarkable advances in the sheet metal forming analysis by the finite element method. In order to save the time and the effort in the product and process design, the finite element approach is indispensable for accurate sheet metal forming analysis. The computational efficiency becomes the important issue when the lead time should be reduced by making the discrepancy between the analysis and the reality as slight as possible. Finite element analysis of the sheet metal forming problem usually adopts one of three analysis methods based on the membrane, shell and continuum element. The membrane element has been widely used in finite element analysis because of its computational efficiency and better convergence than the shell or continuum element. The membrane element, however, does not consider the bending effect inherently and has to tolerate inaccuracy in the bending dominant problem. To overcome the inaccuracy, a modified membrane element was proposed, which was fortified with the advantage of the shell element by considering the bending effect. The plastic dissipation term was decomposed into the two terms: the term due to the mean stretching throughout the thickness; and the term due to the bending deformation over the thickness. In this paper, by this idea a modified membrane finite element formulation considering bending effect is derived for sheet metal forming analysis of the rigid plastic materials with planar anisotropy obeying Hill's quadratic yield criterion in evaluating the membrane and bending energy term.
  In order to successfully simulate sheet metal forming of planar anisotropic materials, there needs a technique to deal with the blank holding force since the thickness distribution becomes more irregular in the flange region than that for isotropic or normal anisotropic materials. The blank holding force is a very important process variable to have an effect on the deformed shape of a product by controlling the material inflow. In real sheet metal forming, the blank holding force does not act on the whole region of the flange, but on the part where the contact occurs between the sheet metal and the die. Since it depends on the thickness of the sheet metal in the flange region, the blank holding force should be correctly calculated from the thickness variation. This paper proposes a new scheme to effectively apply the blank holding force to the proper flange region in order to predict more accurate deformed shapes in deep drawing processes of sheet metal.
  Cylindrical cup, square cup and rectangular cup drawing processes are simulated by the implemented code for demonstration its validity. In the simulation of cylindrical cup drawing process, the earing phenomenon is exaggerated due to the unrealistic distribution of the blank holding force. This exaggerated simulation of the earing phenomenon can be controlled reasonably by the new scheme proposed where the blank holding force varies with the thickness change. The thickness distribution , the punch load and the flange shape contour are compared with the experimental results. The results from the analysis proposed in this paper are in better agreement with the experimental results than the results from the analysis of normal anisotropic material. In the simulation of square cup and rectangular cup drawing processes, the punch load obtained from the analysis is in good agreement with the experimental result. And to investigate the effect of the rolling direction in the initial blank, the simulations of the rectangular cup drawing are carried out varying the rolling direction in the initial blank. Finally, the effect of the coefficients introduced in the evaluation of the compressive stress due to the blank holding force is investigated. The proper values for the coefficients in rectangular cup drawing process are suggested. Consequently, it is proved that the developed algorithm can predict accurate punch load and deformed shape in deep drawing processes.

번호 제목 저자명 날짜 조회 수
27 Sheet metal forming analysis with a modified membrane finite element formulation considering bending effect (굽힘 효과를 고려한 박막 요소 수식화에 의한 박판 성형 가공 해석) 한수식  2005.11.29 7582
26 Process parameter estimation in sheet metal forming using a finite element inverse method (유한요소 역 해석을 이용한 박판금속 성형의 공정변수 예측) 이충호  2005.11.29 7444
» A Rigid-plastic Finite Element Analysis of Sheet Metal Forming with Planar Anisotropic Materials using a Modified Membrane Element considering Bending Effect (굽힘이 고려된 개량박막요소를 이용한 평면이방 박판금속 성형의 강소성 유한요소 해석) 최태훈  2005.11.29 8692
24 Shell Element Formulation for Limit Analysis of Thin-Walled Structures ( 박판부재의 붕괴거동해석을 위한 극한해석의 쉘요소 수식화 ) 김현섭  2005.11.29 14689
23 Finite Element Simulation of 3-dimensional Superplastic blow forming with diffusion bonding (유한요소법을 이용한 초소성 재료의 삼차원 확산 접합 및 압력 성형 해석) 이기석  2005.11.29 16940
22 Crash Analysis of Auto-body Structures with an Explicit Finite Element Method ( 외연적 유한요소법을 이용한 차체 구조물의 충돌해석 ) 강우종  2005.11.29 16675
21 Optimum Process Design in Sheet Metal Forming Processes using Finite Element Sensitivity Analysis (유한요소 민감도해석을 이용한 박판금속성형에서의 공정변수 최적설계) [1] 김세호  2005.11.29 18448
20 Development of a Nonlinear Degenerated Shell Element with the Drilling Degree of Freedom by the Cubic Polynomial Interpolation and the Assumed Strain Method (드릴링 자유도의 삼차 근사법과 대체변형률법을 이용한 비선형 감절점 쉘 요소의 개발) 이형욱  2005.11.29 17660
19 Finite Element Inverse Approach and Initial Guess Generation for Sheet Metal Forming Analysis of Complicated Auto-body Members (복잡한 차체부재의 박판성형공정을 위한 유한요소 역해석 및 초기추측치 계산) 김승호  2005.11.29 19048
18 Dynamic Formulation of Finite Element Limit Analysis for Impact Simulation of Structural Members (구조부재의 충돌해석을 위한 유한요소 극한해석의 동적 수식화) 김기풍  2005.11.29 17723
17 Study on Dynamic Tensile Tests of Auto-body Steel Sheet at the Intermediate Strain Rate for Material Constitutive Equations (차체강판의 중변형률 속도에서의 동적 인장시험 및 물성 구성방정식에 관한 연구) 임지호  2005.11.29 25428
16 A Study on the Dynamic Failure Model of a Spot Weld under Combined Loading Conditions for Auto-body Crash Analyses (차체용 부재의 충돌해석을 위한 복합하중조건에서 점용접부의 동적 파단모델 연구) [1] 송정한  2008.07.24 18508
15 Analysis of Elasto-Plastic Stress Waves by a Time Discontinuous Variational Integrator of Hamiltonian with a Second-Order Integration Scheme of the Constitutive Model (해밀토니안의 시간 불연속 변분적분기와 구성방정식의 2차 정확도 적분법을 이용한 탄소 조상순  2008.12.15 21644
14 Microscopic investigation of the strain rate hardening for auto-body steel sheet(차체강판 변형률속도 경화의 미시적 관찰) 윤종헌  2010.07.13 16886
13 A Study on Material Properties of OFHC Copper Film at High Strain Rates using High-Speed Micro Material Testing Machine (고속마이크로재료시험기를 이용한 무산소동 박판의 고변형률속도 재료물성치 연구) 김진성  2010.07.13 20155
12 Evaluation of a cast-joining process of dual metal crankshafts for heavy-duty engines with ductile cast iron and high strength forged steel(구상흑연주철과 고강도 단조강의 주조접합 이종금속을 이용한 중대형 엔진 크랭크샤프트의 평가) 한 신  2010.07.13 17826
11 Forming Limit Diagram of Auto-body Steel Sheets at High Strain Rates for Sheet Metal Forming and Crashworthiness (박판성형 및 충돌성능 향상을 위한 고변형률속도에서의 차체강판 성형한계도) 김석봉  2010.07.13 21582
10 A Study on the Tension/Compression Hardening Behavior of Auto-body Steel Sheets Considering the Pre-strain and the Strain Rate (초기 변형률 및 변형률 속도를 고려한 차체 강판의 인장/압축 경화 거동에 관한 연구) [1] 배기현  2011.01.11 20274
9 A Study on a Continuum Damage Yield Function to Predict Ductile Fracture of Materials (재료의 연성파단을 예측하기 위한 연속체 손상 항복 함수에 관한 연구) 고윤기  2012.12.10 14563
8 Measurement Uncertainty Evaluation for High Strain Rate Tensile Properties of Auto-body Steel Sheet (자동차용 강판 고속인장물성 데이터의 측정불확도 산출) 정세환  2012.12.10 17701