저자명 이충호 
년도 1997 
Sheet metal forming processes experience very complicated deformations effected by process parameters such as the blank shape, blank holding force, bead force, die geometry, sheet thickness, friction, lubrication, and so on. Although these process parameters influence the deformation mechanism and the quality of deformed parts, the optimum values of process parameters are determined by intuition and experience through trial and error. A more systematic method such as finite element analysis can simulate complicated sheet metal forming processes and provide useful information. However, general finite element analysis is generally carried out with given process parameters and thus requires numerical trial and error with enormous time and cost to determine the optimum values of process parameters. For this reason, some approaches to find directly the process parameters have been developed. However, most design purpose approaches have shortcomings such as geometric restriction, neglecting variation of material properties due to deformation path, and path-independent boundary conditions which causes deformation error. In order to overcome such problems, a new finite element inverse method is introduced for direct prediction of the blank shapes and strain distributions from desired final shapes. The finite element inverse method enables the determination of process parameters within a small error range in good computing time before the process design. The finite element inverse method in this papers adopts Hencky's deformation theory. Hill's anisotropic yield criterion, and simplified boundary conditions. The proposed initial guess scheme using linear inverse mapping enables applications of general shapes to the finite element inverse method effectively. The finite element inverse method with the optimization scheme can calculate non-shape parameters directly as well as shape parameters. The (one step) inverse method is, then, extended to the multi-step inverse method in order to reduce the amount of error. The present algorithm has been implemented in a finite element code and applied to several sheet metal forming examples for demonstration of its validity. As a bench mark test, the algorithm was first applied to drawing of cylindrical and square cup. Blank shapes and thickness strain distributions were obtained. And then, experiments were carried out using blank specimens prepared for the calculated blank shape; Secondly, simulations of more complicated geometries such as oil pan and front fender were conducted as a demonstration of the programs capability and versatility. Third, non-shape parameters such as blank holding force and bead force were also estimated directly with a proper scheme optimizing objective functions. Finally, the multi-step inverse method was applied to a square cup. The error induced by the one step inverse analysis was reduced significantly by the three step analysis. The process parameters of the above examples were calculated rapidly within a small range of error. Consequently, these examples fully demonstrate that the developed algorithm is a good finite element code for the purpose of process design.

번호 제목 저자명 날짜 조회 수
27 Anisotropic Fracture Limit for the Failure Prediction of Advanced High-Strength Steel Sheets (고강도 강판의 파괴 예측을 위한 이방성 파괴 한계에 관한 연구) 박남수  2017.06.07 2187
26 Rate-Dependent Hardening Model for Polymer-Bonded Explosives Considering a Wide Range of Strain Rates (광범위한 변형률속도를 고려한 복합화약의 변형률속도 의존 경화모델) 박충희  2013.08.30 5072
25 A Study on the Nonlinear Behaviors of Polymer-Bonded Explosives Considering Stress Softening Effect(응력연화현상을 고려한 복합화약의 비선형 거동에 관한 연구) 염기선  2013.09.08 6509
» 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 8661
23 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 8871
22 Dynamic Failure Criteria of a Laser-welded Region under Combined Loading Conditions for Auto-body Crash Analyses (차체용 부재의 충돌해석을 위한 복합하중조건에서 레이저 용접부의 동적 파단조건 연구) 하지웅  2013.04.14 9089
21 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 9850
20 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 15982
19 Shell Element Formulation for Limit Analysis of Thin-Walled Structures ( 박판부재의 붕괴거동해석을 위한 극한해석의 쉘요소 수식화 ) 김현섭  2005.11.29 16090
18 Crash Analysis of Auto-body Structures with an Explicit Finite Element Method ( 외연적 유한요소법을 이용한 차체 구조물의 충돌해석 ) 강우종  2005.11.29 17968
17 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 18300
16 Microscopic investigation of the strain rate hardening for auto-body steel sheet(차체강판 변형률속도 경화의 미시적 관찰) 윤종헌  2010.07.13 18412
15 Rate Dependent Hardening Model for Pure Titanium Considering the Effect of Deformation Twinning (쌍정의 영향을 고려한 티타늄의 변형률속도 의존 경화 모델) 안광현  2012.12.12 18793
14 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 19032
13 Dynamic Formulation of Finite Element Limit Analysis for Impact Simulation of Structural Members (구조부재의 충돌해석을 위한 유한요소 극한해석의 동적 수식화) 김기풍  2005.11.29 19036
12 Measurement Uncertainty Evaluation for High Strain Rate Tensile Properties of Auto-body Steel Sheet (자동차용 강판 고속인장물성 데이터의 측정불확도 산출) 정세환  2012.12.10 19136
11 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 19220
10 Strain-Rate Dependent Anisotropic Yield Criteria for Auto-body Steel Sheets (자동차용 강판의 변형률속도 의존 이방성 항복함수에 관한 연구) 허지향  2012.12.11 19817
9 Optimum Process Design in Sheet Metal Forming Processes using Finite Element Sensitivity Analysis (유한요소 민감도해석을 이용한 박판금속성형에서의 공정변수 최적설계) [1] 김세호  2005.11.29 20103
8 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 20285