저자명 김승호 
년도 1998 
Since permanent magnets of Nd-Fe-B group  were produced on a commercial scale in 1984, they  have kept a  key post  in the permanent magnet market and they are expected to  continue  steady and  remarkable  growth.  The  magnets are currently used in electric machines, high energy motors , generators, sensors and so on. The permanent magnets  of  Nd-Fe-B  group are  manufactured by the sintering  process,  the GM Process ( Rapid Solidification  and  Hot  Forming Process )  and  the  HDDR  Process ( Hydrogenation  Decomposition  Desorption Recombination Process ).  All processes are protected by a patent against its application without  license. In order to overcome  this obstacle  of patent, the tube process was developed and patented. However, it has some problems to produce on  a commercial  scale. This process  causes more flash due to large height  reduction of a deformable  tube, and non-uniformly densified magnets. The process also reduces  the effective magnet area  with flash  and fails to produce efficient magnets with non-uniformly densifica-tion.In  this  study,  a  rigid-plastic  finite element analysis  considering  the compressibility  of  the  powder material  has been carried out  using 8-node hexahedral  isoparametric  elements.  The  analysis  also  deals with contact treatment using the displacement constraints  at the rigid contact  and adopt skew  boundary  conditions and arbitrarily  curved die surface treatment. The finite element program  developed  is  applied to  a class of  sinter-forging problems  with  powder  materials.  The  problem  includes  sinter-forging of cylindrical  green powder and tube processing of compac-tion of green powder. The  tubed compaction  is carried out  on a flat die  or a curved die  with a predicted preform.  The purpose of  the analysis  is to design an appropriate preform for net shape sinter-forging. In order to design a preform, a trial-and-error method is used  considering the thickness  of a tube,  the friction factor, the  curved  shape  of  dies,  and  the slope of  the tube wall. The application   demonstrates  the   validity   of  the present  algorithms  and successfully  suggests  a  appropriate  preform  to get uniform densification with reduced flash in the tube process.

번호 제목 저자명 날짜 조회 수
49 Elasto-plastic finite element method with directional reduced integration in sheet metal forming( 선향적 저감 적분을 이용한 탄소성 유한 요소법에 의한 박판성형해석 ) 한수식  2005.11.29 2716
48 Numerical simulation of an extrusion process (유한요소 극한 해석을 이용한 가공경화재료의 압출공정해석) 이충호  2005.11.29 4465
47 Numerical simulation of bead formation by an elasto-plastic finite element method (탄소성 유한요소법을 이용한 비드 성형의 수치해석) 천병관  2005.11.29 2799
46 Numerical simulations of sheet forming processes by an elasto-plastic finite element method (탄소성 유한요소법을 이용한 박판 성형 공정 해석) [1] 최태훈  2005.11.29 2944
45 Finite element simulation of superplastic sheet forming with initial non-uniform thickness distribution (초기 두께분포가 있는 초소성 재료의 유한요소 성형해석) 최영준  2005.11.29 2975
44 Numerical simulation of superplastic forming with pressure control using a membrane finite element method (초소성 재료의 압력제어성형에 관한 박막유한요소해석) [1] 이기석  2005.11.29 4173
43 Effective experimental method for identification of the forming limit diagram of sheet metals (금속 박판의 성형한계도를 구하기 위한 실험방법 개선에 관한 연구) 정제웅  2005.11.29 3030
42 Load-carrying capacity of axisymmetric pressure vessels using finite element limit analysis (유한요소 극한해석을 이용한 축대칭 압력용기의 하중지지능력 해석) 김현섭  2005.11.29 7272
41 Stress evaluation in plane strain problems by elasto-plastic finite element analysis with reduced integration (저감적분 탄소성 유한요소해석에 의한 평면변형문제에서의 응력계산) [1] 김세호  2005.11.29 4375
40 Plastic collapse analysis of hollow pipe structures by finite element limit analysis (유한요소 극한해석을 이용한 중공 파이프 구조물의 소성 붕괴 거동 해석 ) 서종관  2005.11.29 3438
39 Electrothermal analysis of large electric current systems by finite element method (유한요소법을 이용한 대전류 시스템의 전열해석 ) 강우종  2005.11.29 4222
38 Finite element stress analysis for a coil spring with a multi-level substructuring method(다단계 부분구조법을 이용한 코일스프링의 변형에 관한 유한요소 해석) [1] [1] 김진영  2005.11.29 4869
37 Design of process parameters in axisymmetric multi-step deep drawing by a finite element inverse method (유한요소 역 해석을 이용한 축대칭 다단계 박판성형에서의 공정변수 설계에 관한 연구) 조천수  2005.11.29 3325
36 Self contact analysis of rubber-boots for C. V. joints by a 3-D finite element method (3차원 유한요소법을 이용한 등속조인트 고무 부트의 자체접촉해석) 이형욱  2005.11.29 3433
35 Analyisis of Adiabatic Shear Band Formation by an Elasto-Plastic Finite Element Method with Explicit Time Integration (외연적 시간적분 탄소성 유한요소법에 의한 단열전단밴드의 해석) 조상순  2005.11.29 6711
» Preform Design for Net Shape Sinter-forging of Powdered Magnets with Curved Shape (곡면 형상을 가지는 분말 자석의 정형 가공을 위한 예비성형체의 설계) 김승호  2005.11.29 3729
33 Characterization of the Mechanical Properties of Fiber-reinforced Rubber-matrix Composite Materials (섬유보강 고무모재 복합재료의 기계적 물성치 결정) 안형택  2005.11.29 5212
32 Experiment and Finite Element Analysis of the Formation of Adiabatic Shear Band in Sheet Metal (박판금속의 단열전단밴드 생성에 대한 실험 및 유한요소 해석) 임지호  2005.11.29 3301
31 Three-dimensional Finite Element Analysis of Air Springs with Fiber-reinforced Rubber Composites (섬유강화 고무복합재 공기스프링의 3차원 유한요소 해석) 신진원  2005.11.29 3488
30 Finite Element Analysis and Process Parameter Design for the Tension Levelling of Metallic Strips (금속판재의 인장교정에 대한 유한요소 해석 및 공정변수 설계) 박상래  2005.11.29 5871