• Title/Summary/Keyword: bending wave

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Far-Infrared Emission Characteristics of Germanium Included Fabrics for Emotional Garment (게르마늄 함유 감성의류용 직물의 원적외선 방출 특성)

  • Kim, Hyun-Ah;Kim, Seung-Jin
    • Science of Emotion and Sensibility
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    • v.13 no.4
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    • pp.687-692
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    • 2010
  • This paper surveys emission characteristics of Far-infrared of the fabrics fabricated with germanium imbedded sheath-core conjugate composite filaments. For this purpose, master batch chip was prepared with PET semi-dull chip and nano sized germanium particles and sheath-core type conjugate composite filament was spun using this master batch chip and polyester semi dull. The emission power and emissivity of the germanium imbedded fabrics were measured and investigated using FT-IR spectrophotometer by KICM- FIR 1005 measurement method. In addition, the fabric mechanical properties were measured and discussed with the effects of the optimum texturing process conditions and fabric structural design conditions. The sheath/core type PET composite germanium imbedded filaments were manufactured by the optimum spinning condition, its tenacity and breaking strain showed the same level as the regular PET filament. The tenacity and breaking strain of the DTY showed good physical properties and no problem in the weaving process. Then, wet and dry shrinkages showed higher values than those of regular PET filament. The emission power of the germanium imbedded fabric was $3.53{\times}10^2W/m^2$ at the $5-20{\mu}m$ wave length range, and emissivity was 0.874. The fabric hand of germanium imbedded fabrics was inhanced by the optimum texturing process and fabric structural design with improved mechanical properties such as fabric bending and compressional properties.

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Study on Fatigue Behavior and Rehabilitation of Stringer with Coped Section(I) -Experimental Study on Static and Fatigue Behavior- (절취부를 갖는 세로보의 피로거동과 보수·보강에 관한 연구(I) -정적거동 및 피로거동의 실험적 고찰-)

  • Hwang, Yoon Koog;Chang, Dong Il
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.363-375
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    • 1997
  • This study encompasses the performance of static and fatigue test for the 8 large scale test specimens to clarify the fatigue behavior of coped stringer and the effect of the repair and strengthening on the damaged stringer of the floor system in steel railway bridges. For the purpose of the research, the actual stress wave for the existing bridge was measured, the basic stress range frequency histogram was made and the equivalent stress range was calculated. Using the result from the equivalent stress range made by adjusting the stress range, the static and fatigue test was carried out by identifying the previous rehabilitation and after. As the result of the static tests, it was revealed that the level of local stress under the S1 specimen test of the real equivalent stress range was similar to tensile strength of the test material, and it was consistent with the requirement of the initiation condition of the fatigue crack. Through the various rehabilitation methods to the damaged specimens, the effects of the repair and reinforcement were analyzed. According to the results of the repair of effect, bolting the high tension bolt over the stop hole was confirmed to be more adequate method than drilling only stop hole to delay the fatigue crack growth. Futhermore, in case of the stringer subjected by bending moment, the reinforcement over the upper flange side was determined to be a useful strengthening method, and the reinforcement to the web of the stringer was not appropriate to accomodate as a adequate strengthening method. Also it was confirmed that the category of the fatigue design for the coped stringer met with the category E specified on the fatigue design criteria of the Highway Standard Specification in Korea.

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Fatigue Lives of Pavement Concrete According to Fatigue Test Methods (실험방법에 따른 포장 콘크리트의 피로수명)

  • Yun, Kyong-Ku;Kim, Dong-Ho;Hong, Chang-Woo
    • International Journal of Highway Engineering
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    • v.5 no.3 s.17
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    • pp.11-20
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    • 2003
  • Concrete structures such as bridges, pavement, and offshore structures are normally subjected to repeated load. Because highway and airfield pavements are to resist tension in bending, fatigue failure behavior is very important the fatigue life of materials. Therefore, in this paper was carried according to the fatigue test method and experiment variables for pavement concrete. The fatigue tests were applied split tension($150{\times}75$ in size) and flexural($150mm{\times}150mm{\times}550mm$ in size) beam fatigue test method. Major experimental variable in the fatigue tests in order to consideration of fatigue life were conducted loading frequency of 1, 5, 10, 20Hz and loading shape of block, sine, triangle and moisture condition of dry and wet condition and curing age of 28day and 56day. The test results show that the effect of loading frequency increasing the frequency increased fatigue life, decreased significant at frequencies below 200 cycles. The effect of loading wave form on fatigue life show that a block decreased, triangular increased in comparison with sine. The effect of moisture condition decreased in wet condition in comparison with dry condition. The effect of curing age increased in 564ays in comparison with 28day.

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Estimation of Applicability of Empirical Design Procedure for Predicting Seismic Response of Buried Gas Pipelines through 3D Time-history Analysis (3차원 시간이력해석을 통한 매설가스배관 종방향 지진응답 예측을 위한 경험적 설계법의 적용성 평가)

  • Kwak, Hyungjoo;Park, Duhee;Lee, Jangguen;Kang, Jaemo
    • Journal of the Korean Geotechnical Society
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    • v.31 no.9
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    • pp.53-68
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    • 2015
  • Longitudinal strain is an important component of seismic design for buried pipelines. A design procedure which determines the wavelength from site natural period and shear wave velocity of the soil layer and closed-form solutions of pipelines under a harmonic motion is typically used in design. However, the applicability of the procedure has not yet been thoroughly investigated. In this paper, displacement-time histories extracted from 1D site response analyses are used in 3D shell-spring model to accurately predict the response of pipelines. The results are closely compared to those from the design procedure. The area of interest is East Siberia. Performing a site response analysis to determine site specific displacement time history is highlighted. The site natural period may be used to predict the predominant period of the acceleration time history, but cannot be used to estimate the predominant period of the displacement time history. If an accurate estimate of the predominant period of the displacement time history is provided, it is demonstrated that the design equation can be successfully used to predict the response of pipelines.

Design Methodology on Steel-type Breakwater II. Pile Design Procedure (철재형 이안제 설계기법 연구 II. 하부기초 설계 단계)

  • Kwon, Oh-Kyun;Oh, Se-Boong;Kweon, Hyuck-Min
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.3
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    • pp.219-228
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    • 2011
  • In this paper, the design procedure of substructure of the steel-type breakwater was described and the actual foundation design was performed for the test bed. The site investigation was executed at the Osan-port area, in Uljin, Gyeongbuk, where the steeltype detached breakwater is constructed. The foundation mainly depends on the lateral load and uplift force due to the wave force. Since the superstructure is stuck out about 9.0m from the ocean bed, the foundation must resist on the lateral force and bending moment. After considering various factors, the foundation type of this structure was determined by the steel pipe pile(${\varphi}711{\times}t12mm$). On the stability of pile foundation, the safety factors of the pile on the compressive, lateral and uplift forces were grater than the minimum factor of safety. The displacements of pile under the working load were evaluated as the values below the permissible ones. Based on the subgrade reaction method, we evaluated the relationship of subgrade reaction and displacement for the lateral and the vertical directions in the layers. The structural analyses along with the foundation were perfomed and the effect of pile foundations were compared quantitatively.

Influence of Detailed Structure and Curvature of Woven Fabric on the Luminescence Effect of Wearable Optical Fiber Fabric (직물의 세부 구조 및 굴곡이 웨어러블 광섬유의 발광 효과에 미치는 영향)

  • Yang, Jin-Hee;Cho, Hyun-Seung;Kwak, Hwy-Kuen;Oh, Yun-Jung;Lee, Joo-Hyeon
    • Science of Emotion and Sensibility
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    • v.21 no.4
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    • pp.55-62
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    • 2018
  • The two main requirements of wearable optical fiber fabrics are that they must presuppose a high degree of flexibility and they must maintain the luminance effect in both flat and bent conformations. Therefore, woven optical fiber fabrics that satisfy the above conditions were developed by both weaving and by using computer embroidery. First, we measured the brightness of the wearable optical fiber fabric in the flat state at a total of 10 measurement points at intervals of 1 cm. Second, the wearable optical fiber fabric was placed horizontally on the forearm, where three-dimensional bending occurs, and the luminance values were recorded at the same 10 measurement points. For the woven fabric in the flat state, the maximum, minimum, average, and standard deviation luminance values were $5.23cd/m^2$, $2.74cd/m^2$, $3.56cd/m^2$, and $1.11cd/m^2$, respectively. The corresponding luminance values from the bent forearm were $7.92cd/m^2$ (maximum), $2.37cd/m^2$ (minimum), $4.42cd/m^2$ (average), and $2.16cd/m^2$ (standard deviation). In the case of the computer-embroidered fabric, the maximum, minimum, average, and standard deviation luminance values in the flat state were $7.56cd/m^2$, $3.84cd/m^2$, $5.13cd/m^2$, and $1.04cd/m^2$, respectively, and in the bent forearm state were $9.6cd/m^2$, $3.63cd/m^2$, $6.13cd/m^2$, and $2.26cd/m^2$, respectively. Therefore, the computer-embroidered fabric exhibited a higher luminous effect than the woven fabric because the detailed structure reduced light-loss due to the backside fabric. In both types of wearable optical fiber fabric the luminance at the forearm was 124% and 119%, respectively, and the light emitting effect of the optical fiber fabric was maintained even when bent by the human body. This is consistent with the principle of Huygens, which defines the wave theory of light, and also the Huygens-Fresnel-Kirchhoff principle, which states that the intensity of light increases according to the magnitude of the angle of propagation of the light wavefront (${\theta}$).