• 제목, 요약, 키워드: Multiple Material

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다중재료 구조물의 위상 최적화를 위한 재료혼합법의 개발 (Development of a Material Mixing Method for Topology Optimization of Multiple Material Structures)

  • 한석영;이수경
    • 대한기계학회논문집A
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    • v.28 no.6
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    • pp.726-731
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    • 2004
  • This paper suggests a material mixing method to mix several materials in a structure. This method is based on ESO(Evolutionary Structural Optimization), which has been used to optimize topology of only one material structure. In this study, two criterions for material transformation and element removal are implemented for mixing several materials in a structure. Optimal topology for a multiple material structure can be obtained through repetitive application of the two criterions at each iteration. Two practical design examples of a short cantilever are presented to illustrate validity of the suggested material mixing method. It is found that the suggested method works very well and a multiple material structure has more stiffness than one material structure has under the same mass.

다중 양중장비와 자재 야적 위치의 최적 결정을 위한 모델 개발 (Optimization of Multiple Tower Cranes and Material Stockyards Layout)

  • 김경주;김경민;이상규
    • 한국건설관리학회논문집
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    • v.10 no.6
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    • pp.127-134
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    • 2009
  • 본 연구에서는 여러 대의 타워 크레인이 다양한 후보지점을 갖고, 자재 역시 다양한 야적 후좌지점을 가질 때 자재 운반 최적화를 지원하기 위한 유전자 알고리즘 기반의 모델을 제시하고자 한다. 대형 건축공사에서 타워 크레인의 위치와 자재 야적 위치의 변화는 자재 운반시간의 변화를 가져온다. 또한 여러 대의 타워 크레인을 사용하는 경우 각 자재의 운반에 어떠한 타워 크레인을 배정하느냐에 따라 작업의 효율성이 변화한다. 따라서 본 연구에서는 다중의 타워 크레인 설치 후보지, 여러 종류의 자재, 자재 야적 후보지점간의 다양하고 복잡한 상관관계를 다루기 위하여 유전자 알고리즘을 적용한 다중 양중장비 및 자재 야적 위치 최적화모델을 제시하였다. 또한, 제시된 모델을 사례에 적용하여 적용 과정을 예시하고 활용성을 검증하였다.

진화적 구조 최적화를 이용한 재료 혼합법의 개발 (Development of a Material Mixing Method using ESO)

  • 한석영;이수경;신민석
    • 한국공작기계학회:학술대회논문집
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    • pp.259-264
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    • 2003
  • This paper suggests a material mixing method to mix several materials in a structure. This method is based on ESO(Evolutionary Structural Optimization), which has been used to optimize topology of only one material structure. In this study, two criterions for material transformation and element removal are implemented for mixing several materials in a structure. Optimal topology for a multiple material structure can be obtained through repetitive application of the two criterions at each iteration. Two practical design examples of a short cantilever are presented to illustrate validity of the suggested material mixing method. It is found that the suggested method works very well and a multiple material structure has more stiffness than one material structure has under the same mass.

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비정상 열 하중을 받는 이질재료의 다중 크랙 문제 (Multi-Crack Problems for Non-homogeneous Material Subjected to Unsteady Thermal Load)

  • 김귀섭
    • 한국항공운항학회지
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    • v.19 no.1
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    • pp.15-23
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    • 2011
  • The purpose of this paper is to investigate the time behavior of a multiple crack problems. It is assumed that the medium contains cracks perpendicular to the crack surfaces, that the thermo-mechanical properties are continuous functions of the thickness coordinate. we use the laminated composite plate model to simulate the material non-homogeneity. By utilizing the Laplace transform and Fourier transform techniques, the multiple crack problems in the non-homogeneous medium is formulated. Singular integral equations are derived and solved to investigate the multiple crack problems. As a numerical illustration, transient thermal stress intensity factors(TSIFs) for a functionally graded material plate subjected to sudden heating on its boundary are provided. The variation in the TSIFs due to the change in material gradient and the crack position is studied.

다중재료 광조형장치 개발 (Development of a Multi-material Stereolithography System)

  • 김호찬;최재원
    • 한국정밀공학회지
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    • v.27 no.3
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    • pp.135-141
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    • 2010
  • Researchers continue to explore possibilities for expanding additive manufacturing (AM) technologies into direct product manufacturing. One limitation is in the materials available for use in AM that can meet the needs of end-use applications. Stereolithography (SL) is an AM technology well known for its precision and high quality surface finish capabilities. SL builds parts by selectively crosslinking or solidifying photo-curable liquid resins, and the resin industry has been continuously developing new resins with improved performance characteristics. This paper introduces a unique SL machine that can fabricate parts out of multiple SL materials. The technology is based on using multiple vats positioned on a rotating vat carousel that contain different photo-curable materials. To change the material during the process, the build platform is raised out of the current vat, a new vat with a different material is rotated under the platform, and the platform is submerged into the new vat so that the new material can be used. This paper introduces a new vat exchange mechanism, cleaning process, recoating process, resin leveling mechanism and process planning technologies for the implementation of multiple material SL. An overview of the system framework is provided and the system integration and control software is described. In addition, several multiple material test parts are designed, fabricated, and described.

복합재질로 구성된 건축 구조체의 열전달 수치해석을 위한 ISI10211모델계산 (Numerical analysis of heat transfer for architectural structure composed of multiple materials in ISO10211)

  • 이주희;박지호;이용준
    • KIEAE Journal
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    • v.16 no.6
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    • pp.159-166
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    • 2016
  • Purpose: The architectural structures in the engineering field include more than one material, and the heat transfer through these multiple materials becomes complicated. More or less, the analytic solutions obtained by the hand calculation can provide the limited information of heat transfer phenomena. However, the engineers have generally been forced to obtain reliable results than those of the hand calculation. The numerical calculation such as a finite volume methods with the unstructured grid system is only the suitable means of the analysis for the complex and arbitrary domains that consists of multiple materials. In this study, a new numerical code is developed to provide temperature distributions in the multiple material domains, and the results of this code are compared with the validation cases in ISO10211. Method: Finite volume methods with an unstructured grid is employed. In terms of numerical methods, the heat transfer conduction coefficient is not defined on the surface of the cell between different material cells. The heat transfer coefficient is properly defined to accurately mimic the heat transfer through the surface. The boundary conditions of heat flux considering radiation or heat convection are also developed. Result: The comparison between numerical results and ISO 10211 cases. We are confirmed that the numerical method provides the proper temperature distributions, and the heat transfer equation and its boundary conditions are developed properly.

Simultaneous Optimization of Multiple Quality Characteristics in Laser Beam Cutting Using Taguchi Method

  • Dubey, Avanish Kumar;Yadava, Vinod
    • International Journal of Precision Engineering and Manufacturing
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    • v.8 no.4
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    • pp.10-15
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    • 2007
  • Taguchi methods have been used for a long time to improve the product quality and process performance of a manufacturing system, Few researchers have applied this methodology in laser beam cutting (LBC) of sheet metals and found the considerable improvement in cut qualities. In all experimental investigations of LBC so far, the objective was to optimize the single quality characteristic at a time. In this paper the simultaneous optimization of multiple quality characteristics such as Kerf width and material removal rate (MRR) during pulsed Nd:YAG LBC of thin sheet of magnetic material (high Silicon-steel) has been presented using Taguchi's quality loss function. The results show the considerable improvement in multiple S/N ratio as compared to initial cutting condition. Also, the comparison of results from single and multi-objective optimization have been presented and it was found that the loss in quality is always possible shifting from single quality to multiple quality optimization.

다중반사 구조를 갖는 복합구조물의 RCS 감소를 위한 광대역 다층 전파흡수체 설계 (Broad-band Multi-layered Radar Absorbing Material Design for Radar Cross Section Reduction of Complex Targets Consisting of Multiple Reflection Structures)

  • 김국현;조대승;김진형
    • 대한조선학회논문집
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    • v.44 no.4
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    • pp.445-450
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    • 2007
  • An optimum design process of the broad-band multi-layered radar absorbing material, using genetic algorithm, is established for the radar cross section reduction of a complex target, which consists of multiple reflection structures, such as surface warships. It follows the successive process of radar cross section analysis, scattering center analysis, radar absorbing material design, and reanalysis of radar cross section after applying the radar absorbing material. It is demonstrated that it is very effective even in the optimum design of the multi-layer radar absorbing material. This results from the fact that the three factors, i.e.. the incident angle range, broad-band frequencies, and maximum thickness can be simultaneously taken into account by adopting the genetic algorithm.

Multi-material topology optimization of Reissner-Mindlin plates using MITC4

  • Banh, Thien Thanh;Lee, Dongkyu
    • Steel and Composite Structures
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    • v.27 no.1
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    • pp.27-33
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    • 2018
  • In this study, a mixed-interpolated tensorial component 4 nodes method (MITC4) is treated as a numerical analysis model for topology optimization using multiple materials assigned within Reissner-Mindlin plates. Multi-material optimal topology and shape are produced as alternative plate retrofit designs to provide reasonable material assignments based on stress distributions. Element density distribution contours of mixing multiple material densities are linked to Solid Isotropic Material with Penalization (SIMP) as a design model. Mathematical formulation of multi-material topology optimization problem solving minimum compliance is an alternating active-phase algorithm with the Gauss-Seidel version as an optimization model of optimality criteria. Numerical examples illustrate the reliability and accuracy of the present design method for multi-material topology optimization with Reissner-Mindlin plates using MITC4 elements and steel materials.