• Title/Summary/Keyword: Superplastic forming/diffusion bonding (SPF/DB)

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Finite Element Analysis of Superplastic Forming/Diffusion Bonding Processes (초소성 성형/확산접합 공정의 유한요소 해석)

  • 홍성석;김용환
    • Transactions of Materials Processing
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    • v.5 no.1
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    • pp.37-46
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    • 1996
  • Superplastic forming/diffusion bonding (SPF/DB) processes were analyzed using a rigid visco-plastic finite element method. The optimum pressure-time relationship for a target strain rate and thickness distributions were predicted by two-node line elements based on the membrane approximation for plane strain. Material behavior during SPF/DB of the integral structures having complicated shapes was investigated. The tying condition is employed for the analysis of inter-sheet contact problems. A movement of rib structure is successfully predicted during the forming.

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Process Design of Superplastic Forming/Diffusion Bonding by Using Design of Experiment (실험계획법을 이용한 초소성 성형/확산접합의 공정설계)

  • Song, J.S.;Kang, Y.K.;Hong, S.S.;Kwon, Y.N.;Lee, J.H.;Kim, Y.H.
    • Transactions of Materials Processing
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    • v.16 no.2 s.92
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    • pp.144-149
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    • 2007
  • The superplastic forming/diffusion bonding(SPF/DB) is widely used in the automotive and aerospace industry because it has great advantage to produce complex, light and strong parts. But the superplastic forming process requires much forming time and generates excessive thinning in the thickness distribution of formed part. It is necessary to minimize trial and error for SPF/DB Process. Finite element analysis using $L_{18}$ orthogonal may table of Taguchi method for 3-Sheet D/B process is carried out. Through the study, effect of process parameters, such as DH region size, thickness and friction coefficient, is evaluated and the optimum condition is derived.

Analysis of superplastic forming/diffusion bonding process using a finite element method (유한요소법을 이용한 초소성 성형/확산접합 공정해석)

  • Song, J.S.;Kim, Y.H.;Hong, S.S.;Kang, Y.K.;Lee, J.H.;Kwon, Y.N.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.265-268
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    • 2006
  • The superplastic forming/diffusion bonding is widely accepted as an advanced technique for forming complex industrial components. But the superplastic forming process requires much forming time and generates excessive thinning thickness distribution of formed part. Superplastic in materials is only achieved in a narrow range of strain-rate with optimum value unique to each material. In this study, finite element analysis for surperplastic forming/diffusion bonding (SPF/DB) processes of three-sheet and four-sheet sandwich parts. From this study, forming analysis have offered a lot of information for developing the forming process.

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Process design of superplastic forming/diffusion bonding by using pressure control (압력제어를 이용한 초소성 성형/확산접합의 공정설계)

  • Song, J.S.;Kang, K.Y.;Hong, S.S.;Kwon, Y.N.;Lee, J.H.;Kim, Y.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.332-335
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    • 2007
  • The superplastic forming (SPF) has been widely used in the automotive and aerospace industry because it has great advantages to produce very light and strong components. Finite element method (FEM) is used to model the process of superplastic forming/diffusion bonding (SPF/DB), to predict the pressure-time curve and to analyze the process parameter. In this study, process design of SPF/DB is carried out a 3-sheet sandwich part. SPF/DB process with pressure control was analyzed by using finite element method. For obtaining proper shape, step-by-step pressurization is proposed. The first step of SPD/DB process is obtained by applying of pressure in patches. From the next step it applied pressure to all regions (between inner sheets, between inner and face sheets). By using the proposed pressurization scheme, deficit in part shape is found to be eliminated.

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Process Design of Superplastic Forming/Diffusion Bonding by Using Step-by-step Pressurization (단계적 가압을 이용한 초소성 성형/확산접합의 공정설계)

  • Song, J.S.;Kang, Y.K.;Hong, S.S.;Kwon, Y.N.;Lee, J.H.;Kim, Y.H.
    • Transactions of Materials Processing
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    • v.16 no.4 s.94
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    • pp.239-243
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    • 2007
  • Superplastic forming/diffusion bonding(SPF/DB) has been widely used in the automotive and aerospace industry since it has great advantages to produce very light and strong components. Finite element method(FEM) is used to model the SPF/DB process of 3-sheet sandwich panel to predict the pressure-time curve and to analyze the process parameters. In order to eliminate defects of the part, a new pressurization scheme is proposed. Contrary to the conventional one-step pressurization, which causes the folding at the DB joint, two-step pressurization can eliminate the folding. Effect of pressurization cycle was investigated by using FE analysis and proper pressurization cycle is proposed.

3-D Finite Element Analysis of Superplastic Forming/Diffusion Bonding Processes with Consideration of Contact between Deformable Bodies (변형체간의 접촉을 고려한 3차원 초소성 성형/확산접합의 유한요소해석)

  • Kang, Yung-Kil;Song, Jae-Sun;Hong, Sung-Suk;Kim, Yong-Hwan
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.1
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    • pp.57-65
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    • 2008
  • Superplastic forming/diffusion bonding(SPF/DB) processes with inner contact were analyzed using a 3-D rigid visco-plastic finite element method. A constant-triangular element based on membrane approximation and an incremental theory of plasticity are employed for the formulation. The hierarchical search algorithm for the contact searching has been applied. The algorithms for contact force processing were designed to handle equally well contact between deformable bodies, as well as rigid bodies. The plate of three and four sheets for 3-D SPF/DB model are analyzed using the developed program. The validity for the analysis is verified by comparison between analysis, experiment and results in the literature.

Superplastic Forming /Diffusion Bonding Processes Design Using a Finite Element Method (유한요소법을 이용한 초소성 성형/확산접합 공정 설계)

  • 홍성석;이종수;김용환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.03a
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    • pp.155-161
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    • 1995
  • Superplastic forming/diffusion bonding(SPF/DB) processes are analyzed using a rigid visco-plastic finite element method. The optimum pressure-time relationship for a target strain rate and thickness distributions were predicted using two-node line element based on membrane approximation for plane strain shapes. Material behavior during SPF/DB of the integral structures with complicated shapes are investigated. The tying condition is employed for the analysis inter-sheet contact problems. A movement of rib structure is successfully prodicted during the forming.

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Analysis of 3-D Superplastic Forming/Diffusion Bonding Process Using a Hierarchical Contact Searching Method(I) (계층적 접촉 탐색방법을 이용한 3-D 초소성 성형/확산접합의 공정설계(I))

  • Kang, Y.K.;Song, J.S.;Hong, S.S.;Kwon, Y.N.;Lee, J.H.;Kim, Y.H.
    • Transactions of Materials Processing
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    • v.16 no.2 s.92
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    • pp.138-143
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    • 2007
  • Superplastic forming/diffusion bonding (SPF/DB) processes were analyzed using a 3-D rigid visco-plastic finite element method. A constant-triangular element based on membrane approximation and an incremental theory of plasticity are employed for the formulation. The coulomb friction law is used for interface friction between tool and material. Pressure-time relationship for a given optimal strain rate is calculated by stress and pressure values at the previous iteration step. In order to improve the contact searching, hierarchical search algorithm has been applied and implemented into the code. Various geometries including sandwich panel and 3 sheet shape for 3-D SPF/DB model are analyzed using the developed program. The validity fer the analysis is verified by comparison between analysis and results in the literature.

Fabrication of Lightweight Sandwich Structural Components with Superplastic Forming/Diffusion Bonding Technology (초소성/확산접합 기술을 이용한 티타늄 샌드위치 경량구조물 제작)

  • Lee, Ho-Sung;Yoon, Jong-Hoon;Yi, Yeong-Moo;Shin, Dong Hyuk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.9
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    • pp.778-782
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    • 2007
  • In the present study, design and forming process of fabricating titianium lightweight components are developed with applicaton of superplastic forming and diffusion bonding technology. SPF/DB(Superplastic forming/Diffusion bonding) technology is one of the advanced technologies to reduce production cost and weight and currently applied to aircrafts and space launchers in foreign countries. The present study constructs an analysis model to predict superplastic forming behavior of titanium alloy, which is well known for its resistance to deform. The experimental results show the forming of titanium lightweight sandwich structure is successfully performed from 3 sheets of Ti-6Al-4V. The results demonstrate that the developed technology to process design of SPF/DB by the finite element method can be applied to various types of components.

Development of Superplastic Forming/Diffusion Bonding Technology for Ti-6Al-4V Sandwich Panels (Ti-6Al-4V 샌드위치 패널제작을 위한 초소성/확산접합 기술개발)

  • Lee, Ho-Sung;Yoon, Jong-Hoon;Lee, Seung-Chul;Park, Dong-Kyu;Yi, Yeong-Moo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.3
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    • pp.123-128
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    • 2008
  • Ti-6Al-4V alloy is a critical strategic metal used in aerospace structure due to the high specific strength, toughness, durability, low density, corrosion resistance. Examples of application of this alloy are airframe structural components, aircraft gas turbine disks and blades. Forming of this alloy is not easy due to its high strength and low formability. However, this alloy shows superplastic properties that allow for large plastic deformation under certain conditions. Combination of superplastic forming and diffusion bonding(SPF/DB) processes of this alloy has been widely used to replace mechanically fastened structures with reduced weight and fabrication costs. In this study, superplastic forming/diffusion bonding technology has been developed for fabricating lightweight sandwich panels with Ti-6Al-4V alloy. The experimental results show the forming of titanium lightweight sandwich structure is successfully performed from 3 and 4 sheets of Ti-6Al-4V.