• Title/Summary/Keyword: Optimum Reinforcement

검색결과 187건 처리시간 0.022초

현장 강우재현시험을 통한 방조제 사면필터층의 필터성능분석 (Evaluation of Filter Capacity for Sea Dyke Slope Filter Layer by In-situ Rainfall Test)

  • 오영인;김서룡;유전용;김현태
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2006년도 춘계 학술발표회 논문집
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    • pp.828-837
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    • 2006
  • Geotextiles consist of three major types of geosynthetic material (woven, non-woven and composite) and the functions of geotextiles are separation, reinforcement, filtration, drainage and as a moisture barrier. Although the many research scholar and engineer developed and established the design criteria and construction methodology, sustainable research still needed for optimum design methodology to the complicate field conditions. In this study, in-situ rainfall test performed to develop suitable filter system for sea dyke upper slope filter layer. In-situ rainfall test conducted for seven different filter system and measured the infiltration flux and pore pressure at various filter layer. Based on the test results, the double layered geotextile filter and sand transition system is most suitable for sea dyke upper filter layer because which system is effective for drainage of infiltration flow and minimize the deformation of sea dyke cover stone.

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교번흐름 조건에 따른 토목섬유 필터층의 재료분리 및 지오텍스타일의 피로영향 분석 (Fatigue Effect and Particle Rearrangement of Geosynthetics Filter Layer with Cyclic Flow Conditions)

  • 오영인;유전용;김현태
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.1554-1561
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    • 2005
  • Geotextiles form one of the two largest groups of geosynthetics and it is consisted two major types of synthetic material (Woven, Non-woven). The functions of geotextiles are separation, reinforcement, filtration, drainage and as a moisture barrier. Within these functions, however, there are a large number of applications or use areas. Although the many research scholar and engineer developed and established the design criteria and construction methodology of geosynthetics filter layer, because the lack of suitable design terminology and uncertainty of long term durability, sustainable research still needed for optimum design methodology to the complicate field conditions. Especially, more intensive research needed about under the cyclic flow condition and fine silty sand base material. In this paper, the filter model test performed under cyclic flow with various boundary conditions (period and frequency of cyclic flow, types of geosynthetic filter material, surcharge etc.).

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Computational Lagrangian Multiplier Method by using for optimization and sensitivity analysis of rectangular reinforced concrete beams

  • Shariat, Mehran;Shariati, Mahdi;Madadi, Amirhossein;Wakil, Karzan
    • Steel and Composite Structures
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    • 제29권2호
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    • pp.243-256
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    • 2018
  • This study conducts an optimization and sensitivity analysis on rectangular reinforced concrete (RC) beam using Lagrangian Multiplier Method (LMM) as programming optimization computer soft ware. The analysis is conducted to obtain the minimum design cost for both singly and doubly RC beams according to the specifications of three regulations of American concrete institute (ACI), British regulation (BS), and Iranian concrete regulation (ICS). Moreover, a sensitivity analysis on cost is performed with respect to the effective parameters such as length, width, and depth of beam, and area of reinforcement. Accordingly, various curves are developed to be feasibly utilized in design of RC beams. Numerical examples are also represented to better illustrate the design steps. The results indicate that instead of complex optimization relationships, the LMM can be used to minimize the cost of singly and doubly reinforced beams with different boundary conditions. The results of the sensitivity analysis on LMM indicate that each regulation can provide the most optimal values at specific situations. Therefore, using the graphs proposed for different design conditions can effectively help the designer (without necessity of primary optimization knowledge) choose the best regulation and values of design parameters.

사출성형공정에서 유리섬유함유량이 인장강도에 미치는 영향 (Effect of Glass Fiber Contents on the Tensile Strength in Injection Molding Process)

  • 김영수;김인관
    • 한국정밀공학회지
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    • 제17권5호
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    • pp.63-69
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    • 2000
  • The main target of this research is investigating the relations between mechanical properties and injection conditions, like injection pressure, packing pressure and packing time for various contents ratio of glass fiber and resin. In general idea, high injection pressure produces high strength of molded parts as a monotonic function. but it was revealed that high pressure does not make high strength directly through various experiments of injection molding. In this experiments, PA66 was selected as resin and Glass Fiber was selected as reinforcing fiber Fiber reinforcement was controlled, as 14%, 25%, 33%, 44% of total volume and packing pressure was divided 55%, 65%, 75%, 85% of reference pressure, i.e. 100% equal to 1400kgf/$\textrm{cm}^2$. Finally, tensile testing was executed for injected test specimen. Optimum results based on authors' experiments have been obtained under conditions of 25% and 33% of glass fiber contents. Tensile strength rather depends on the packing pressure and packing time than injection pressure. Especially almost equal value of tensile strength was obtained for various percentage of packing and injection pressure as 65%, 75% and 85% of reference pressure.

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고온 프레스법에 의한 TiNi/Al2024 복합재료의 제조 및 기계적 특성평가 (Fabrication and Mechanical Properties of TiNi/Al2024 Composites by Hot-Press Method)

  • 손용규;배동수;박영철;이규창
    • 소성∙가공
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    • 제18권1호
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    • pp.45-51
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    • 2009
  • Shape memory alloy has been used to improve the tensile strength of composite by the occurrence of compressive residual stress in matrix using its shape memory effect. In order to fabricate shape memory alloy composite, TiNi alloy fiber and Al2024 sheets were used as reinforcing material and matrix, respectively. In this study, TiNi/Al2024 shape memory alloy composite was made by using hot press method. In order to investigate bonding condition between TiNi reinforcement and Al matrix, the micro-structure of interface was observed by using optical microscope and diffusion layer of interface was measured by using Electron Probe Micro Analyser. And the mechanical properties of composite with three parameters(volume fraction of fiber, cold rolling amount and test temperature) were obtained by tensile test. The most optimum bonding condition for fabrication the TiNi/Al2024 composite material was obtained as holding for 30min. under the pressure of 60MPa at 793K. The strength of composite material increased considerably with the volume fraction of fiber up to 7.0%. And the tensile strength of this composite increased with the reduction ratio and it also depends on the volume fraction of fiber.

고강도 철근콘크리트 보의 전단거동에 관한 실험적 연구 (An Experimental Study on Shear Behaviour of Reinforced High Strength Concrete Beams)

  • 곽계환;고갑수;곽경헌
    • 한국농공학회지
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    • 제38권3호
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    • pp.58-69
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    • 1996
  • In recent years, the research and development about the new material proceeds rapidly and actively. In building industry, high strength concrete is of interest as a new material. Since the building structure becomes bigger, higher and more specialized, the demand of material and member with high strength expands greatly. Therefore in this experiment, cement complex with high strength was made using the condensed silica fume, a basic experiment was performed on strength property, and optimum-mixture-state was determined for manufacturing a high-strength concrete. Shear behaviour and fracture property of concrete beams with high strength were evaluated. On the whole, in spite of many researches, it is one of the difficult problems that shear fracture of concrete beams has not yet been clearly understood theoretically, and now the shear-design-standard forms in many countries are a formula based on experiment. In this study, the variable of shear behavior experiment was shear-reinforcement-ratio. By analyzing test results and comparing with computation value by ACI code, the basic data was offered on shear design of reinforced concrete beams with high strength. The effect of epoxy repair was also investigated for the beams with cracks due to flexural and shear loading.

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Variation of Pull-out Resistance of Geogrid with Degree of Saturation of Soil

  • Yoo, Chungsik;ALI, TABISH
    • 한국지반신소재학회논문집
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    • 제19권1호
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    • pp.1-9
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    • 2020
  • This paper presents the results of experimental investigation on the effect of degree of saturation of soil on the pullout behavior of a geogrid. Different test variables were taken into account while performing the experiment including the soil physical conditions based on water content and external loading applied. The soil used was locally available weathered granite soil. The tests included variations in saturation of about 90%, 80%, 70% and 45% (optimum moisture content). The pullout tests were performed according to ASTM standard D 6706-01. The results indicate that increasing the degree of saturation in the soil decreases the pull-out capacity, which in turn decreases the interface friction angle and interaction coefficient. The decrease in the pullout interface coefficient was observed to be around 12.50% to 33.33% depending on the normal load and degree of saturation of the soil. The test results demonstrated the detrimental effect of increasing the degree of saturation within the reinforce soil on the pullout behavior of reinforcement, thus on the internal stability. The practical inferences of the outcomes are analyzed in detail.

OOA 공정을 통한 CFRTP 항공기 Frame 보강재 성형에 관한 연구 (A Study on CFRTP Aircraft Frame Stiffening by OOA Process)

  • 이환주;전용준;최현석;김동언
    • Design & Manufacturing
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    • 제11권2호
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    • pp.15-19
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    • 2017
  • Carbon fiber reinforced plastic (CFRP) is applied as structural material. CFRP is excellent in plane strength / stiffness and don't haves rust. Lightweight, rigid and robust at the same time as transportation material. Aluminum alloy and reinforcement material The application is increasing rapidly. In this study, the prototype of a semi - Monocoque structure frame, Longeron, Stringer, Skin of the aircraft, restraining the rigidity Clips of the aircraft was designated as the target product and the experiment was conducted. ln the experiment, (1) For CFRTP 3 points, data on heating, transfer, and cooling were measured using Thermo Couple, and optimum temperature required for flexible state was obtained. Heating was performed at a temperature 15% higher than the provided temperature. (2) By using a pneumatic press during molding, by dividing LH, center and RH according to the cooling time, thickness parameter of the target product due to the load is measured, and thickness control and time-deviations were analyzed and cross sections were observed with a low magnification microscope.

In-situ 용탕혼합 합성법에 의한 Al-TiB2 복합재료의 LES 기법 모델링 및 제조 (LES Method Modeling and Fabrication of Al-TiB2 Composite by In-situ Melt Mixing Process)

  • 박정수;김종훈;하만영;박봉규;박영호;박익민
    • 대한금속재료학회지
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    • 제46권6호
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    • pp.382-389
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    • 2008
  • To manufacture Al MMCs, in-situ melt mixing process is used because it is free from contamination, and it makes reinforcements homogeneously dispersed. Large eddy simulation method is used to find the optimum melt mixing condition. At the Re 3000, the most suitable mixing is occurred between Al-Ti and Al- B melts. The in-situ formed $TiB_2$ particles has the size varying from 40 nm to 130 nm, due to the increase of cooling rate, and exhibits a homogeneous dispersion. And the interface between reinforcement and matrix is clean. Both hardness and Young's modulus of this composite are improved with increasing the cooling rate.

Equivalent reinforcement isotropic model for fracture investigation of orthotropic materials

  • Fakoor, Mahdi;Rafiee, Roham;Zare, Shahab
    • Steel and Composite Structures
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    • 제30권1호
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    • pp.1-12
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    • 2019
  • In this research, an efficient mixed mode I/II fracture criterion is developed for fracture investigation of orthotropic materials wherein crack is placed along the fibers. This criterion is developed based on extension of well-known Maximum Tensile Stress (MTS) criterion in conjunction with a novel material model titled as Equivalent Reinforced Isotropic Model (ERIM). In this model, orthotropic material is replaced with an isotropic matrix reinforced with fibers. A comparison between available experimental observations and theoretical estimation implies on capability of developed criterion for predicting both crack propagation direction and fracture instance, wherein the achieved fracture limit curves are also compatible with fracture mechanism of orthotic materials. It is also shown that unlike isotropic materials, fracture toughness of orthotic materials in mode $I(K)_{IC}{\mid})$ cannot be introduced as the maximum load bearing capacity and thus new fracture mechanics property, named here as maximum orthotropic fracture toughness in mode $I(K_{IC}{\mid}^{ortho}_{max})$ is defined. Optimum angle between crack and fiber direction for maximum load bearing in orthotropic materials is also defined.