• Title/Summary/Keyword: Solid support

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Elastic Buckling Analysis of Laminated Composite Plates with Embedded Square Delamination Using an Enhanced Assumed Strain Solid Element (강화변형률 솔리드 요소를 사용한 사각형태 층간분리를 갖는 복합적층판의 탄성좌굴해석)

  • Park, Dae-Yong;Chang, Suk-Yoon
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.1 no.2
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    • pp.1-13
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    • 2010
  • Delamination reduces an elastic buckling load of the laminated composite structures and lead to global structural failure at loads below the design level. Therefore, the problem of the delamination buckling of laminated composite structures has generated significant research interest and has been the subject of many theoretical and experimental investigations. However, questions still remain regarding a complete understanding and details of the phenomena involved. In this paper an efficient finite element model is presented for analyzing the elastic buckling behavior of laminated composite plates with square embedded delamination using a solid element based on a three-dimensional theory. The solid finite element, named by EAS-SOLID8, based on an enhanced assumed strain method is developed. The study for elastic buckling behavior of laminated composite plates with embedded square delaminations are focused on various parameters, such as support condition and width-to-thickness ratio. Both graphs and buckling modes in this paper are good guide for design of the laminated composite plates with embedded square delamination.

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A Study of Fuel-rich Solid Propellant Characteristic for Boron-bead Particle Size (금속연료인 과립화붕소의 입도에 따른 연료과농 고체 추진제 특성 연구)

  • Won, Jongung;Choi, Sunghan;Lee, Wonbok;Kim, Junhyung;Hwang, Gabsung;Park, Bocksun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.5
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    • pp.12-18
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    • 2014
  • A study of gas generator Fuel-Rich propellant for air-breathing propulsion system was performed in this paper. General solid propellant comprises a mean of 60% or more oxidizing agents. but, to develop the fuel-rich solid propellant increased the content of the metal fuel and reduced the content of the oxidizing agents by approximately 30%. Very high amount of heat per volume of fuel into the metal having the Boron was used. Amorphous Boron Powder was applied to propellant as beads type and it allowed to design more amount of metal fuel in the fuel-rich propellant. And the Combustion characteristics and properties of fuel-rich solid propellant according to the Boron-bead sizes were confirmed.

Single cell property and numerical analysis of metal-supported solid oxide fuel cell (금속지지체형 고체산화물 연료전지의 단전지 특성 및 전산해석)

  • Lee, Chang-Bo;Bae, Joong-Myeon
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2222-2227
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    • 2007
  • Newly structured metal-supported solid oxide fuel cell was fabricated and characterized by impedance analysis and galvanodynamic experiment. Using a cermet adhesive, thin ceramic layer composed of anode(Ni/YSZ) and electrolyte(YSZ) was joined with STS430 metal support of which flow channel was fabricated. $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_3$ perovskite oxide was used as cathode material. Single cell performance was increased and saturated at operating time to 300hours at 800$^{\circ}C$ because of cathode sintering effect. The sintering effect was reinvestigated by half cell test and exchange current density was measured as 0.005A/$cm^2$. Maximum power density of the cell was 0.09W/$cm^2$ at 800$^{\circ}C$. Numerical analysis was carried out to classify main factors influencing the single cell performances. Compared to experimental IV curve, simulated curve based on experimental parameters such as exchange current density was in good agreement.

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A Study on the Product Design and Prototype Manufacturing of a Plastic V-Belt Pulley (플라스틱 V-벨트 풀리 설계 및 시작품 제작에 관한 연구)

  • Son, Tae-Yil;Rim, Jae-Kyu;Kim, Hyung-Jong
    • Journal of Industrial Technology
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    • v.21 no.B
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    • pp.281-286
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    • 2001
  • In this study, product design and prototype manufacturing of a plastic water-pump pulley has been tried. The designed model is supposed to be made of 33 % glass reinforced resin of which the tensile strength is 180 MPa, and has 24 ribs on each side to increase its structural strength. Structural analysis under a static load of 300 kgf acting on both edges of the belt has been carried out using a commercial finite element code, MARC. The analysis result showed the maximum effective stress near a rib of designed model would be at most 35 MPa (less than 20% of the tensile strength), therefore, the plastic product would be sufficiently safe under that loading condition. On the basis of the structural analysis, a prototype of the designed model has been manufactured by using the fused deposition modelling (FDM) method which is one of the rapid prototyping (RP) methods, using ABS resin and support materials. The CAD data exported to the RP system in STL format was prepared by a commercial solid modeling software, SolidWorks. It has been proved that the plastic pulley can successfully replace the existing flow-formed steel product.

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The impact of Google SketchUp on spatial ability and 3D geometric thinking of 7th grade students in volume measurement of solid figures (공간 능력과 공간 기하적 사고에서 SketchUp활용의 효과 -중학교 1학년 입체도형의 측정 단원을 중심으로-)

  • Lee, Hyun Hui;Kim, Rae Young
    • The Mathematical Education
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    • v.52 no.4
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    • pp.531-547
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    • 2013
  • The purpose of the study is to examine how effects of activities using Google SketchUp on students' spatial ability and 3D geometric thinking in measuring the volume of solid figures. By comparing the results from pre- and post-tests between the experimental group and control group, we found that activities using Google SketchUp help students improve their spatial ability in the spatial orientation and visualization. In addition, more than half students in the experimental group moved from level 4 up to level 7 in thinking process of measuring the volume in terms of Battista(2004)'s levels. This study suggests that the instruction with Google SketchUp can help to improve students' spatial ability and 3D geometric thinking in the regular class in middle school. In addition, SketchUp can be an advanced technological tool to support students' self-directed learning, which create an efficient educational environment and a great opportunity to learn geometry in an effective manner.

A Design for a Home-Built Solid State NMR Spectrometer

  • Yang Doo-Kyung;Zax David B.
    • Journal of the Korean Magnetic Resonance Society
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    • v.10 no.1
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    • pp.74-88
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    • 2006
  • Since the first commercial NMR spectrometer came out in 1953 from Varian, much of the hardware development has been improved and matured through commercial equipments. Many of magnetic resonance laboratories however still build and use home-built spectrometers, which are satisfactory even with the consideration of educational purpose only. The home-built NMR spectrometer could be further advantageous and could be often an only option for investigating new ideas with demanding experimental conditions or new hardware support. A solid state NMR spectrometer was designed with extra interest in stochastic experiment and built for an 8.93 T superconducting magnet from Oxford instrument. Super-heterodyned system was implemented for the transmitter and receiver parts. Intermediate frequency (IF) for the heterodyne system was chosen to 70 MHz for the first and the second channels, with additional 120 MHz for the third channel for maximum NMR frequency capability. We will show overall schematics, and discuss the designs with detailed diagrams, then demonstrate the applicability of home-built spectrometer with stochastic-excitation in solid state NMR and in applications to quadrupolar nuclear Spins.

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Catalytic Conversion of Cellulose to Cellulose Acetate Propionate (CAP) Over SO42-/ZrO2 Solid Acid Catalyst

  • Leng, Yixin;Zhang, Yun;Huang, Chunxiang;Liu, Xiaocheng;Wu, Yuzhen
    • Bulletin of the Korean Chemical Society
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    • v.34 no.4
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    • pp.1160-1164
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    • 2013
  • The solid super acid catalyst $SO{_4}^{2-}$/$ZrO_2$ was prepared by impregnation method using $ZrO_2$ as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). $Al_2O_3$ and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and $NH_3$-TPD. In this paper, the effects of concentration of $H_2SO_4$ impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that $SO{_4}^{2-}/ZrO_2$ successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L $H_2SO_4$ and calcined at $500^{\circ}C$. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at $50^{\circ}C$ for 8 h.

A Study on the Stress Simulation for the Body Design of a PFA-lined Plug Valve (PFA 라이닝 플러그 밸브 설계를 위한 밸브 본체의 응력 시뮬레이션)

  • Kang, Shin-Han
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.3
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    • pp.500-506
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    • 2009
  • This study, is aimed to support the valve design engineer by a CAE simulation on the body of a PFA-lined plug valve, and focuses on static stress analysis, location of the weak point on bending and stiffness of the valve body. To determine whether the valve body can resist being transformed by loads, 1 simulated the stress distribution using CAD/CAE softwares. The 'step' file converted by CAD software after solid modeling is imported to the CAE software. Through simulation procedure, it is shown that the designed-solid-model fur a valve body has stiffness on bending and torsion but has weakness for side bending moment. Also, it is expected that the valve design engineer will understand the basic process of CAE and will be able to apply on his task.

A Study on the Fabrication of 3D Scaffolds Using the Solid Freeform Method (임의 형상 제작 기법을 이용한 3차원 세포지지체 제작에 관한 연구)

  • Choi, Do-Hyun;Kim, Hyun-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.2
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    • pp.44-51
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    • 2019
  • With the goal of tissue regeneration for organs damaged through an accident or a disease, research on tissue engineering has been conducted to produce 3-D scaffolds that can support the cells in the attachment and growth for the cell proliferation and differentiation. A scaffold requires a suitable pore size and porosity to increase the nutrient circulation or oxygen supply for the attachment and growth of cells. The existing production methods such as solvent-casting particulate leaching, phase separation, and fiber bonding have certain disadvantages. With these methods, it is difficult to obtain a free desired shape. In addition, certain pore sizes and interconnectivities among the pores may not be guaranteed. To solve these problems, this study has fabricated a scaffold with a 3-D shaped nose using Alginate, which is a natural polymer obtained through Fused Deposition Modeling (FDM), one of the CAD/CAM-based Solid Freeform Fabrication (SFF) methods.

Characterization and Preparation of Ceramic Interconnect of SOFC by Thermal Plasma Spray Coating Process (열 플라스마 용사법에 의해 코팅된 고체산화물 연료전지용 세라믹 연결재 특성 연구)

  • Park, Kwang-Yeon;Lim, Tak-Hyoung;Lee, Seung-Bok;Park, Seok-Joo;Shin, Dong-Ryul;Song, Rak-Hyun
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.187-190
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    • 2009
  • $LaCrO_3$ series are the most common candidate materials for a ceramic interconnect for SOFC and the thermal expansion coefficient of these matches very well with that of YSZ electrolyte. In this study, characteristics of the coated films on the anode-support, which were formed by using $La_{0.8}Ca_{0.2}CrO_3$, $La_{0.8}Sr_{0.2}CrO_3$, $La_{0.8}Ca_{0.2}Co_{0.1}Cr_{0.9}O_3$ for ceramic interconnet for SOFC, were investigated. All powders showed single perovskite phase and the precursors had spherical shapes of $2{\mu}m{\sim}30{\mu}m$. According to SEM analysis, coated film of LCC on pretreated anode-support was more thicker, whereas the coated film on untreated anode-support was densely formed. As the results of electrical conductivity of anode-support coated with the ceramic interconnects, LCCC exhibited the most excellent electrical conductivity of 0.15S/cm at $750^{\circ}C$.

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