저자명 이형욱 
년도 2003 
Most structural analyses are concerned with the behavior of shell structures that are the effective form of relatively thin and flexible structures. Deformation of the shell structures is generally calculated by the finite element analysis with shell elements. The demand of shell models is rapidly growing in a wide range of finite element analyses of the shell structures in order to perform large-scale computations in complicated three-dimensional problems of structural analyses and forming processes. Among various types of shell elements, the four-node bilinear degenerated shell element is widely used for numerical analysis Many recent efforts have been done to include the sixth degree of freedom of the drilling rotation compatible to the physical meaning.
  In this paper, a four-node degenerated shell element with the drilling DOF is developed to solve nonlinear problems with the implicit numerical scheme based on the Belytschko-Leviathan's shell element and the Zhu-Zacharia's bilinear quadrilateral shell element. The drilling DOF has been interpolated by a cubic polynomial function of the beam deflection mechanism and the assumed strain method for the purpose of eliminating the in-plane shear locking phenomenon induced by the third order polynomial interpolation. A suitable assumed strain method for the drilling DOF is obtained by the Rayleigh-Ritz method and is applied to portion of the drilling DOF among the in-plane strain components of a shell element. The transverse shear locking phenomenon is prevented by the Dvorkin and Bathe's assumed strain method. The one point integration rule is adopted for the computational efficiency. Since the reduced integration results in spurious energy modes so called hourglass modes, the physical stabilization method is applied in order to control these spurious modes. The shell element developed is extended to deal with the geometric and the material nonlinearities. The material nonlinearity is considered by applying the return mapping method for a plane stress problem by Simo and Taylor in order to deal with the elasto-plastic constitutive model.
  Several benchmark problems and example problems were solved to investigate the performance of the element developed. The eigenvalue analysis confirmed the validity of the developed shell element and the analysis of linear problems demonstrated the accuracy and convergence of the element developed. Results of linear problems demonstrated that the element developed was free from the in-plane shear locking phenomenon and had good convergence and accuracy under the in-plane deformation and the warped geometry even with the coarse mesh system. The result form the full hemispherical shell problem showed that the membrane locking phenomenon still occurred with the coarse mesh system since it was influenced by the term with ξη.
  Nonlinear problems including the geometrical and the material nonlinearities were chosen in order to confirm the versatility of the drilling degree of freedom and the robustness in the large rotational problem. The nonlinear problems of the bending, the torsion, the plate with a hole, collapse of a square box and collapse of a S-rail have been solved with the element developed and the results fully demonstrate the versatility and performance of the developed shell element. Results showed that the element developed was useful not only in linear problems but also in nonlinear problems including the geometrical and the material nonlinearities.

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 7583
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 7445
25 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 16941
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
» 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 17661
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 17724
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 20156
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 21583
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 17702