• Title, Summary, Keyword: Lamination Structure

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Optimal Lamination Design of Composite Cylinders using an Empirical Ultimate Pressure Load Formula (최종강도 경험식을 이용한 복합재 원통구조의 최적적층 설계)

  • Cho, Yoon Sik;Paik, Jeom Kee
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.4
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    • pp.316-326
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    • 2019
  • In this paper, a methodology is presented for determining the optimal lamination of composite cylindrical structures subject to hydrostatic pressure. The strength criterion in association with the process of optimal design is the buckling collapse of composite cylinders under hydrostatic pressure loads. An empirical formula expressed in the form of the Merchant-Rankine equation is used to calculate the ultimate strength of filament-wound composite cylinders where genetic algorithm is applied for determining the optimized stacking sequences. It is shown that the optimized lamination provides improved collapse pressure loads. It is concluded that the developed method would be useful for the optimal lamination design of composite cylindrical structures.

Lamination of LTCC Sheet Using Binder Film (Binder Film을 이용한 LTCC Sheet 적층)

  • Shin, Hyo-Soon;Choi, Yong-Seok;Park, Eun-Tae
    • Journal of the Korean Ceramic Society
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    • v.43 no.4
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    • pp.253-258
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    • 2006
  • In the lamination process of multi-layer ceramic modules, the occurrence of delamination comes into repeatedly. To completely improve the lamination process of LTCC sheets, a binder film was introduced between the layers. The binder film did not originate the delamination until the thickness under $40{\mu}m$. After lamination, the thickness of the binder film was determined by the infilteraion of binder by the pressure, and after the bake-out, was dependent on the decomposition of binder resin. Any detectable defect was not observed in the multilayer structure with Ag inner electrodes.

A 3-D Structural Analysis of Composite Sabot (복합재 이탈피의 3차원 구조해석)

  • 이성호;이강우;박관진;송흥섭
    • Journal of the Korea Institute of Military Science and Technology
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    • v.6 no.2
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    • pp.65-72
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    • 2003
  • Composite sabot can increase the penetration performance of APFSDS projectile by reduction of the sabot weight. However, it has a thick-sectioned lamination and the lamination structure is different from those of the conventional composite parts. In this study, modeling technique for a thick and radially-laminated composite part has been applied in the finite element analysis of composite sabot. Four models of composite lamination for the sabot have been proposed and evaluated for their structural strength.

Study on Numerical-analysis Technique for Windpower System Structure under Environmental Loadings (환경하중하의 풍력발전 시스템 구조물의 수치 해석적 기법 연구)

  • Jung, Hae-Young;Hong, Cheol-Hyun
    • Journal of Ocean Engineering and Technology
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    • v.25 no.5
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    • pp.69-75
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    • 2011
  • The purpose of this study was to develop a buckling analysis technique for a windpower system structure under environmental loadings (hydrostatic pressure) using FEM. We analyzed an isotropic material and composite material and made a comparison using buckling pressure formulas. First, finite element analyses for an isotropic material (SC410) were performed to obtain the variation of buckling pressure for the number of elements and boundary conditions in a pressure-shell model, and the numerical results were compared with those of existing empirical formulas. Then, additional finite element analyses based on the results of the isotropic material (SC410) were performed to determine the optimum lamination angle and pattern for a composite material (URN300). The results of the FE analyses for the composite material were also compared with those of existing empirical formulas. The ply orientations (lamination angles) used in the FE analyses were $0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$, and. The lamination patterns in the FE analyses were and. The lamination pattern was assumed to be the equivalent model of. The results of the FE analyses for the isotropic material (SC410) indicated that the optimal values for the number of elements and the boundary conditions were 6000 and both simply supported, respectively. The results of the FE analyses for the composite material (URN300) showed that the optimal ply orientation was $60^{\circ}{\sim}75^{\circ}$.

Processing of Functionally Graded Materials via Green Tape Lamination

  • Cho, Yu-Jeong;Kim, Yong-Seog
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.78-79
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    • 2003
  • A functionally graded material was produced by laminating green tapes. The lamination resulted in the formation of functionally graded structure and sintering of the materials resulted of FGM. This results demonstrated a possibility of using green tapes in the processing of functionally graded materials.

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Collaborative optimization for ring-stiffened composite pressure hull of underwater vehicle based on lamination parameters

  • Li, Bin;Pang, Yong-jie;Cheng, Yan-xue;Zhu, Xiao-meng
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.9 no.4
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    • pp.373-381
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    • 2017
  • A Collaborative Optimization (CO) methodology for ring-stiffened composite material pressure hull of underwater vehicle is proposed. Structural stability and material strength are both examined. Lamination parameters of laminated plates are introduced to improve the optimization efficiency. Approximation models are established based on the Ellipsoidal Basis Function (EBF) neural network to replace the finite element analysis in layout optimizers. On the basis of a two-level optimization, the simultaneous structure material collaborative optimization for the pressure vessel is implemented. The optimal configuration of metal liner and frames and composite material is obtained with the comprehensive consideration of structure and material performances. The weight of the composite pressure hull decreases by 30.3% after optimization and the validation is carried out. Collaborative optimization based on the lamination parameters can optimize the composite pressure hull effectively, as well as provide a solution for low efficiency and non-convergence of direct optimization with design variables.

Optimum Design for Iso-strain Structure of Hybrid Laminated Composite (하이브리드 적층복합재료에서의 Iso-Strain 구조설계의 최적화)

  • 강선교;이경우;강태진
    • Composites Research
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    • v.13 no.3
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    • pp.21-29
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    • 2000
  • The optimum design of hybrid laminated composites for iso-strain structure has been studied by controling fiber orientations and thicknesses of each layer. Fiber orientations and thicknesses of each layer for iso-strain structure were designed. Combining the laminates of each layer of different reinforcing material, the constitutions of hybrid laminated composite for iso-strain structure were obtained. All these calculations were formed on computer systems, automatically for the hybridization. Using the data of some specific laminated composite such as glass and aramid reinforced composites, the constitutions of hybrid laminated composites for iso-strains structure were designed and verified by lamination theory. The strains of each layer of hybrid laminated composites are calculated and they turned out to be good agreements with the results obtained lamination theory.

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Hybrid Coextrusion and Lamination Process for Macrochanneled Bioceramic Scaffolds

  • Koh, Young-Hag;Bae, Chang-Jun;Kim, Hyoun-Ee
    • Journal of the Korean Ceramic Society
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    • v.41 no.7
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    • pp.497-502
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    • 2004
  • A hybrid coextrusion and lamination process has been developed to fabricate macrochanneled bioceramic scaffolds. This process was mainly composed of three steps (i.e., coextrusion of thermoplastic compound, lamination, and thermal treatment), forming unique pore channels in dense bioceramic body. Pore channels were formed by removing carbon black material, while calcium phosphate or Tetragonal Zirconia Polycrystals (TZP) with a calcium phosphate coating layer were used as dense body. Two kinds of pore structures were fabricated; that is, the pore channels were formed in uni- or three-directional array. Such macrochanneled bioceramic scaffolds exhibited the precisely controlled pore structure (pore size, porosity, and interconnection), offering excellent mechanical properties and cellular responses.

Curved laminate analysis

  • Chiang., Yih-Cherng
    • Structural Engineering and Mechanics
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    • v.39 no.2
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    • pp.169-186
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    • 2011
  • This paper is devoted to the development of the equations which describe the elastic response of a curved laminate subjected to in-plane loads and bending moments. Similar to the classic $6{\times}6$ ABD matrix constitutive relation of a flat laminate, a new $6{\times}6$ matrix constitutive relation between force resultants, moment resultants, mid-plane strains and deformed curvatures for a curved laminate is formulated. This curved lamination theory will provide the fundamental basis for the analyses of curved laminated structures. The stress predictions by the present curved lamination theory are compared to those by the curved laminate analysis that neglected the nonlinear terms in the derivation of the constitutive relation. The results show that the curved laminate analysis that neglected the nonlinear terms cannot reflect the effect of curvature and can no longer predict the stresses accurately as the curvature becomes noticeable. In this paper, a curved lamination theory that retains the nonlinear terms and, therefore, accounts for the effect of the non-flat geometry of the structure will be developed.

Rotordynamic Model Development with Consideration of Rotor Core Laminations for 2.2 kW-Class Squirrel-Cage Type Induction Motors and Influence Investigation of Bearing Clearance (2.2 kW급 유도전동기의 회전자 적층구조를 고려한 회전체 동역학 해석모델 개발 및 베어링 간극의 영향 분석)

  • Park, Jisu;Sim, Kyuho;Lee, Sung-Ho
    • Tribology and Lubricants
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    • v.35 no.3
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    • pp.158-168
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    • 2019
  • This paper presents the investigation of two types of rotordynamic modeling issues for 2.2 kW-class, rated speed of 1,800 rpm, squirrel-cage type induction motors. These issues include the lamination structure of rotor cores, and the radial clearance of ball bearings that support the shaft of the motor. Firstly, we focus on identifying the effects of rotor core lamination on the rotordynamic analysis via a 2D prediction model. The influence of lamination is considered as the change in the elastic modulus of the rotor core, which is determined by a modification factor ranging from 0 to 1.0. The analysis results show that the unbalanced response of the rotor-bearing system significantly varies depending on the value of the modification factor. Through modal testing of the system, the modification factor of 0.079 is proven to be appropriate to consider the effects of lamination. Next, we investigate the influence of ball bearing clearance on the rotordynamic analysis by establishing a bearing analysis model based on Hertz's contact theory. The analysis results indicate that negative clearance greatly changes the bearing static behavior. Rotordynamic analysis using predicted bearing stiffness with various clearances from -0.005 mm to 0.010 mm reveals that variations in clearance result in a slight difference in the displacement of the system up to 18.18. Thus, considering lamination in rotordynamic analysis is necessary as it can cause serious analysis errors in unbalanced response. However, considering the effect of the bearing clearance is optional because of its relatively weak impact.