• Title, Summary, Keyword: Membrane material

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Tests of Fire and Flame Retardant Performance for Membrane Materials (막재료의 난연 및 방염성능 실험에 대한 연구)

  • Kim, Gee-Cheol;Choi, Kwang-Ho
    • Journal of the Korean Association for Spatial Structures
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    • v.16 no.2
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    • pp.55-60
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    • 2016
  • The Membrane structure has a number of problems in the application of a fireproof code based on general buildings codes. Thus, the fireproof code of membrane structure is necessary to activate the construction of the membrane structure. Because it requires a systematic classification of fire retardant and flame proof performance of membrane material. Fire retardant and flame proof tests are conducted on membrane materials mostly used in current construction to propose the fire and flame retardant performance criteria of membrane materials. Fire and flame retardant tests results, PTFE membrane material with the glass fiber fabric have a limit-combustible performance. PVDF membrane material with the polyester fabric does not ensure the fire retardant performance, but this membrane material has the flame retardant performance of a thick fabric. Also, ETFE does not ensure the fire retardant performance, but this membrane material has the flame retardant of a thin fabric.

Effect of compressible membrane's nonlinear stress-strain behavior on spiral case structure

  • Zhang, Qi-Ling;Wu, He-Gao
    • Structural Engineering and Mechanics
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    • v.42 no.1
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    • pp.73-93
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    • 2012
  • With an active structural involvement in spiral case structure (SCS) that is always the design and research focus of hydroelectric power plant (HPP), the compressible membrane sandwiched between steel spiral case and surrounding reinforced concrete was often assumed to be linear elastic material in conventional design analysis of SCS. Unfortunately considerable previous studies have proved that the foam material serving as membrane exhibits essentially nonlinear mechanical behavior. In order to clarify the effect of membrane (foam) material's nonlinear stress-strain behavior on SCS, this work performed a case study on SCS with a compressible membrane using the ABAQUS code after a sound calibration of the employed constitutive model describing foam material. In view of the successful capture of fitted stress-strain curve of test by the FEM program, we recommend an application and dissemination of the simulation technique employed in this work for membrane material description to structural designers of SCS. Even more important, the case study argues that taking into account the nonlinear stress-strain response of membrane material in loading process is definitely essential. However, we hold it unnecessary to consider the membrane material's hysteresis and additionally, employment of nonlinear elastic model for membrane material description is adequate to the structural design of SCS. Understanding and accepting these concepts will help to analyze and predict the structural performance of SCS more accurately in design effort.

Sound Absorption and Thermal Insulation Characteristics of Membrane Used for Sound Field Control (음장제어용 막재료의 음향 및 단열특성)

  • Jeong, Jeong-Ho;Kim, Jeong-Uk;Jeong, Jae-Gun;Cho, Byung-Wook
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.2
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    • pp.103-114
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    • 2012
  • Nowadays membrane material is widely used for large indoor spaces and long spaces such as traditional market. Thermal insulation and sound field control performance is considered as a main properties for design of such buildings. In this paper sound absorption and thermal insulation properties of membrane material was investigated. Firstly, normal incidence sound absorption coefficient of 10 kinds of glass wool textiles showed that sound absorption coefficient was increased in proportion of thickness and surface density of textile. Sound absorption coefficient of 4 kinds of sound absorptive inner membrane with outer membrane was tested in the reverberation chamber. Sound absorption coefficient of mid frequency range was about 0.4 ~ 0.6. Also, sound absorption coefficient was changed by the air space behind the membrane material. Secondly, sound field control performance was investigated using mock-up space. By the installation of sound absorption membrane material, reverberation time was decreased and speech intelligibility was increased. Finally, thermal resistance and room temperature in two kinds of mock-up rooms were tested, simultaneously. Results of thermal properties showed thermal insulation properties ware increased by adding inner membrane material underneath the outer membrane.

Sound Absorption Characteristics and Application Effect of PTFE Membrane Material (테프론 막 재료의 흡음특성 및 적용효과 연구)

  • Jeong, Jeong-Ho;Shon, Jang-Ryul;Kim, Jung-Joong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.4
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    • pp.342-349
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    • 2007
  • Following the 2002 World-Cup held in Korea, studies have been actively conducted on plans to utilize all-weather stadiums of fine figures, where large-scale spaces are available for various utilizations. In Japan, dome-type stadiums have been built and are utilizing across the whole nation not only for sports events but also variety of other large-scale events. PTFE(poly tetra fluoro ethylene) is one of the membrane material mainly used for the outer ceiling surface of membrane structures. However, there has not been enough research on the acoustical properties of PTFE membrane material which has been widely used in the multi-purpose stadiums. In this study, air permeability values and sound absorption coefficient of PTFE membrane materials were measured and evaluated in the gymnasium. From the results of measurements of sound absorption coefficient and air permeability of inner membrane materials, it was found that the sound absorption coefficient was good in the air permeability range of $5{\sim}15\;cc/cm^2/s$. Also the relation ship between air permeability and sound absorption coefficient was very high and the sound absorption coefficient was the highest in the range of $6{\sim}9\;cc/cm^2/s$. Secondly, an analysis on the measurements sound absorption characteristics of inner membrane material reveals that the overall sound absorption coefficient was stabilized(higher than 0.5 throughout the whole frequency bands) when the air space behind the membrane material was deeper than 600 mm. When PTFE sound absorptive membrane material was installed in the ceiling of gymnasium, it was confirmed that sound absorptive membrane material can reduce reverberation and increase speech intelligibility in the gymnasium.

Sound Absorption Characteristics of Permeable Membrane (통기성을 갖는 막재료의 흡음특성)

  • Jeong, Jeong-Ho;Kim, Jung-Joong;Kim, Ku-Je
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.270-275
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    • 2009
  • Sound absorption characteristics of membrane system which are used in stadiums and arenas were investigated. Theoretical studies on acoustic properties of single and double leaf permeable membrane conducted. Also, experimental studies on sound absorption characteristics of combined membrane system that is composed of outer and inner membrane material were conducted. In this study, sound absorption characteristics of each membrane were investigated by experiments in reverberation chamber. 4 types of permeable membranes and a non-permeable membrane were used for experiments. Air space behind membrane material and tension on the membrane was varied. Sound absorption performance of permeable membrane materials was confirmed. As increasing air space behind the membrane material, sound absorption coefficient was increased. In a resonance absorption frequency band sound absorption coefficient varied more dramatically. Sound absorption characteristics were flat in mid and high frequency range and sound absorption coefficient was from 0,3 to 0,5. Also sound absorption coefficient was increased by the increment of surface density and air permeability of membrane. However, over the certain value of air permeability, sound absorption coefficient was decreased. These results can be used as design factors and method for the room acoustic design of dome-stadiums and large free-form buildings.

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Present State of Membrane Structures in Japan

  • Oda, Kenshi
    • Journal of The Korean Association for Spatial Structures
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    • v.2 no.2
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    • pp.11-15
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    • 2002
  • Formerly, it was called a tent and now, it is called membrane structure. If saying a tent, it imagines the tent of Bedouin, Mongolia and North American Indian. It became clear from the excavated wall painting that have been covered with the retractable roof of the canvas on the auditorium at the amphitheater in Pompeii and became a topic. These tents were made of the animal skins or fabric woven with the flax plants, and these tents are still used. However, if saying membrane material at present, it says the one to have applied a coating resin to the textile. Because the base fabric of membrane material is a woven fabric, the relation between the stress and the strain is different to the direction of the weaving thread. Moreover, the tensile force must always occur in the membrane surface. From these reasons, because the membrane structure corresponds to the particular building material and the construction method about the Building Standard Law, it must be examined specially that the membrane structural building have the same or any more safety as the provisions which was set to the Building Standard Law. Therefore, the technical standards about the membrane structural building became indispensable. In the paper, the kinds of the membrane materials, which are used for the membrane structural buildings, and technical standards process of the creating for the membrane structure buildings are introduced. Lastly, some of the soccer stadiums for 2002 FIFA World Cup KOREA/JAPAN which be covered with the roof of the membrane structures are presented.

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Test on the Mechanical Characteristics of Glass Fiber Membrane (유리섬유 막재의 역학적 특성에 관한 시험)

  • Park, Kang-Geun;Yoon, Sung-Kee
    • Journal of the Korean Association for Spatial Structures
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    • v.8 no.2
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    • pp.55-62
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    • 2008
  • Membrane structures are now used in various ways throughout the world with the merits of free shape, lightness, durability, sunlight transmittance and homogeneous material. The development of new membrane material opened up new possibility for the design of new building structures. Recently it was mainly used PVC, PVF, PVDF, PTFE, ETFE membrane for using the roofing material of membrane structures. Some problems of membrane materials have fire proofing, lack of strength, self cleaning capacity, tear resistance, durability, heat insulation, sound insulation and elasticity. For the solution of this problems, it will be tested the mechanical properties of membrane material about tensile strength, tearing resistance, etc.

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Characterization of the Nano-material U Membranes with Excellent Fouling Resistance (막 오염 저항성이 우수한 나노 소재 정밀 여과막의 특성 연구)

  • Choi Jeong Hwan;Lee Jeong Bin;Kim In-chul
    • Membrane Journal
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    • v.15 no.4
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    • pp.289-296
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    • 2005
  • In the MBR process, the membrane fouling occurs seriously on the membrane surface. In general, the membrane fouling is attributed to factors such as deposition or adhesion of sludge floc. The occurrence of fouling is a main cause of a decrease in membrane module fluk. At this study, our MBR membrane is manufactured by nano-particle with excellent anti-fouling character. The fine nano-material which can repel the sludge Hoc from the membrane surface is distributed in the membrane surface. We confirm anti-fouling effect, test continuously in the pilot site.

Transport Coefficients across Charged Mosaic Membrane

  • Yang, Wong-Kang
    • Bulletin of the Korean Chemical Society
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    • v.25 no.5
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    • pp.665-667
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    • 2004
  • In previous studies, charged mosaic membranes having two different fixed charges in the membrane matrix indicated unique transport behavior such as preferential material transport. In this study, the composite charged mosaic membrane endurable to mechanical pressure in practical application was investigated from the same aspect of solute and solvent transport as before. Lp and ${\omega}$ estimated by taking account of active layer thickness were satisfactorily consistent with those in mosaic membrane without reinforcement. On the other hand, the reflection coefficient s indicated the negative value that suggests preferential material transport.