• 제목/요약/키워드: Flexible Shape

검색결과 444건 처리시간 0.028초

가변스트레치성형 설계변수와 성형오차의 상관관계에 대한 통계적 연구 (Statistical Study on Correlation Between Design Variable and Shape Error in Flexible Stretch Forming)

  • 서영호;허성찬;강범수;김정
    • 소성∙가공
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    • 제20권2호
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    • pp.124-131
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    • 2011
  • A flexible stretch forming process is useful for small quantity batch production because various shape changes of the flexible die can be achieved conveniently. In this study, the design variables, namely, the punch size, curvature radius and elastic pad thickness, were quantitatively evaluated to understand their influence on sheet formability using statistical methods such as the correlation and regression analyses. Forming simulations were designed and conducted by a three-way factorial design to obtain numerical values of a shape error. Linear relationships between the design variables and the shape error resulted from the Pearson correlation analysis. Subsequently, a regression analysis was also conducted between the design variables and the shape error. A regression equation was derived and used in the flexible die design stage to estimate the shape error.

형상 기억 유연 소자의 내구성 평가에 관한 연구 (Durability of the Flexible Shape Memory Device)

  • 양희경;김해진;김대은
    • 정보저장시스템학회논문집
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    • 제11권2호
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    • pp.36-40
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    • 2015
  • The demand for flexible devices including solar cells, memories and batteries has increased rapidly over the past decades. In most flexible devices, polymer-based materials are used to enable the mechanical deformations such as bending or folding. Shape Memory Polymers (SMPs) is a high molecular compound polymer with flexibility and shape recovery characteristics. In this work, flexible shape memory device was fabricated by simply coating the conducting material, carbon nano-tube (CNT), on a shape memory polymer. Furthermore, durability of the device under various type of mechanical deformations was assessed. It is believed that the result of this work will aid in realization of a stretchable and wearable electronic device for practical applications.

가변성형공정에서 성형성 향상을 위한 해석 및 실험적 연구 (Numerical and Experimental Study for Improvement of Formability in Flexible Forming Process)

  • 허성찬;서영호;강범수;김정
    • 소성∙가공
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    • 제21권7호
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    • pp.432-440
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    • 2012
  • In this article, the design of the flexible forming process considering die shape compensation using an iterative over-bending method based on numerical simulation was conducted. In this method, the springback shape obtained from the final step of the first forming simulation is compared with the desired objective shape, and a shape error is calculated as a vector norm with three-dimensional coordinates. The error vector is inversely added to the objective surface to compensate both the upper and lower flexible die configurations. The flexible die shapes are recalculated and the punch arrays are adjusted according to the over-bent forming surface. These iterative procedures are repeated until the shape error variation converges to a small value. In addition, experimental verification was conducted using a 2000-kN flexible forming apparatus for thick plates. Finally, the configuration of the prototype obtained from the experiment was compared with the numerical simulation results, which had springback compensation. It is confirmed that the proposed method for compensating for the forming error could be used in the design of flexible forming of thick-curved plates.

유한요소법을 이용한 가변스트레치공정 성형변수에 따른 성형오차 경향분석 (Tendency Analysis of Shape Error According to Forming Parameter in Flexible Stretch Forming Process Using Finite Element Method)

  • 서영호;허성찬;송우진;김정;강범수
    • 소성∙가공
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    • 제19권8호
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    • pp.486-493
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    • 2010
  • A shape error of the sheet metal product made by a flexible stretch forming process is occurred by a various forming parameters. A die used in the flexible stretch forming is composed of a punch array to obtain the various objective surfaces using only one die. But gaps between the punches induce the shape error and the defect such as a scratch. Forming parameters of the punch size and the elastic pad to prevent the surface defect must be considered in the flexible die design process. In this study, tendency analysis of shape error according to the forming parameters in the flexible stretch process is conducted using a finite element method. Three forming parameters, which are the punch size, the objective curvature radius and the elastic pad thickness, are considered. Finite element modeling using the punch height calculation algorithm and the evaluation method of the shape error, which is a representative value for the formability of formed surface, are proposed. Consequently, the shape error is in proportion to the punch size and is out of proportion to the objective curvature radius and the elastic pad thickness.

프레스 퀜칭 공정에 의한 자동차 Flexible Plate의 형상 제어 연구 (Shape Control of Automotive Flexible Plate in Press Quenching)

  • 박인회;정우창
    • 열처리공학회지
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    • 제21권4호
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    • pp.189-198
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    • 2008
  • The production of automotive chassis parts requiring both high hardness and good shape-holdability is better realized by using press quenching technology, comprising the austenitizaton and the subsequent press quenching in a specially designed stamping tool. The effect of press quenching mold shape on the hardness distribution, bending height, and degree of planeness of automotive flexible plate during press quenching and tempering has been investigated. The preferable shape of the projections of punch and die in contact with the flexible plate was close to oval to improve the flow of cooling oil, leading to the higher hardness. The press quenching mold with three separate parts was more effective to control the dimensional change due to thermal deformation during press quenching. Some decrease in the bending height during tempering may be related to some recovery of the residual stress at $400^{\circ}C$.

가변롤성형 공정을 이용한 단면이 가변하는 프로파일의 형상변수 분석에 관한 연구 (Investigation of Shape Parameters for a Profile with Variable-cross Sections Produced by Flexible Roll Forming)

  • 박종철;차명환;김돈건;남재복;양동열
    • 소성∙가공
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    • 제23권6호
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    • pp.369-375
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    • 2014
  • Flexible roll forming allows profiles to have variable cross-sections. However, the profile may have some shape errors, such as, warping which is a major defect. The shape error is induced by geometrical deviations in both the concave zone and the convex zone. In the current study, flexible roll forming was modeled with FE simulations to analyze the shape error and the longitudinal strain distribution along the flange section over the profile. A distribution of analytically calculated longitudinal strains was used to develop relationships between the shape error and the longitudinal strain distribution as a function of the defined shape parameters for the profile. The FE simulations showed that the shape error is primarily affected by the deviations between the distribution of analytically calculated longitudinal strain and the longitudinal strain distribution of the profile. The results show that the shape error can be controlled by designing the shape parameters to control the geometrical deviations at the flange section in the transition zones.

자원절약을 위한 가변형 평면계획을 위한 설계원리 (Design Principles for Flexible House Plan corresponding to Resource Saving)

  • 이현수
    • 한국주거학회논문집
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    • 제7권1호
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    • pp.117-126
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    • 1996
  • The purpose of this paper is to develop formal design principles towards flexible house plan. A flexible house plan accomodates spatial requirements corresponding to change of life style and provides a way of saving architectural materials. Design properties as a basis for manipulation of room includes adjacency, orientation and geometrical information which are suited well to flexible design. This paper has developed a formal grammar of shape which can be utilized to transform house plan. Flexible design presented here is based on the idea of various operations of the shape grammar. The shape grammar, as a set of rules, specifies manipulations of shapes for reorganization of spatial relationships of rooms in a house plan. It lists exemplary rules in control knowledge which guides design processes for modifying a plan. An example taken from house plan design is used to ilustrate important aspects of the flexible design which fundamentally provides the basis for architectural material saving.

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요트세일의 형상계측 기법 연구 (A Study on Shape Measuring Technique of a Yacht Sail)

  • 김철희;최정규;김형태
    • 대한조선학회논문집
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    • 제49권1호
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    • pp.93-98
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    • 2012
  • In this study, we introduced image processing technic to measure shape variations of general bodies and applied it to the flexible yacht sail. Shape measurements of simple bodies sails were carried out and results showed that technic can be a reliable method to measure shape variations of the flexible yacht sail. The sail shape variation of 30ft sloop type yacht sail is measured on different sailing conditions. As velocity and direction of wind are increased, trailing edges in the upper part of the sail become more open than the lower part of the sail which are not changed. So it is confirmed that the shape measurement of a sail shape depending on a sailing condition is possible to use image processing scheme.

공동주택 욕실 배기팬의 플랙시블 덕트 시공상태에 따른 환기효율에 관한 연구 (A Study on the Ventilation Efficiency of Apartment Housing Bathroom Based on the Flexible Installation Method of Exhaust Fan.)

  • 이광명;함진식
    • 한국주거학회논문집
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    • 제16권1호
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    • pp.73-79
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    • 2005
  • The ventilation efficiency of apartment housing bathroom has been measured by the flexible's diameter, length, and installation format to the exhaust In. The gas density attenuation method of Tracer Gas Method has been specifically utilized for this measurement. Full size mock-up of apartment housing bathroom, which was approximately $100 m^2$ in size, has been established for the ventilation emciency measurement. In addition, the ventilation efficiency has been studied by the possibility of air-supply In. The diameters of flexible are 100 mm, 125 mm, and 150mm. It also have the length of 1.0m, and 1.5 m. The installation formats are I shape, L shape, and S shape. As a result of this measurement, the flexible which has the highest ventilation efficiency was the one has bigger diameter, short in length, and I shape installation format.

성형 오차 예측 모델을 이용한 가변 성형 공정에서의 탄성 회복 보정 (Compensation for Elastic Recovery in a Flexible Forming Process Using Predictive Models for Shape Error)

  • 서영호;강범수;김정
    • 소성∙가공
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    • 제21권8호
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    • pp.479-484
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    • 2012
  • The objective of this study is to compensate the elastic recovery in the flexible forming process using the predictive models. The target shape was limited to two-dimensional shape having only one curvature radius in the longitudinal-direction. In order to predict the shape error the regression and neural network models were established based on the finite element (FE) simulations. A series of simulations were conducted considering input variables such as the elastic pad thickness, the thickness of plate, and the objective curvature radius. Then, at sampling points in the longitudinal-direction, the shape errors between formed and objective shapes could be calculated from the FE simulations as an output variable. These shape errors were expressed to a representative error value by the root mean square error (RMSE). To obtain the correct objective shape the die shape was adjusted by the closed-loop using the neural network model since the neural network model shows a higher capability of estimating the shape error than the regression model. Finally the experimental result shows that the formed shape almost agreed with the objective shape.