• Title/Summary/Keyword: Spiral test

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Processability and Mechanical Characteristics of Glass Fiber and Carbon Fiber Reinforced PA6 for Reinforcement Content

  • Lee, S.B.;Cho, H.S.;Lyu, M.-Y.
    • Elastomers and Composites
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    • v.50 no.3
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    • pp.184-188
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    • 2015
  • There is a need for light weight and high stiffness characteristics in the building structure as well as aircraft and cars. So fiber reinforced plastic with the addition of reinforcing agent such as glass fiber, carbon fiber, aramid fiber is utilized in this regard. In this study, mechanical strength, flow property and part shrinkage of glass fiber and carbon fiber reinforced PA6 were examined according to reinforcement content such as 10%, 20%, and 30%, and reinforcement type. The mechanical property was measured by a tensile test with specimen fabricated by injection molding and the flow property was measured by spiral test. In addition, we measured the part shrinkage of fiber reinforced PA6 that affects part quality. As glass fiber content increases, mechanical property increased by 75.4 to 182%, and flow property decreased by 18.9 to 39.5%. And part shrinkage decreased by 52.9 to 60.8% in the flow direction, and decreased by 48.2 to 58.1% in the perpendicular to the flow direction. As carbon fiber content increases, mechanical property increased by 180 to 276%, flow property decreased by 26.8 to 42.8%, and part shrinkage decreased by 65.0 to 71.8% and 69.5 to 72.7% in the flow direction and the direction perpendicular to the flow respectively.

Approximate Solution for Constant Velocity of Archimedean Spiral for Abrasion Testing of Rock Cutting Tools (암석공구 마모시험을 위한 아르키메데스 나선의 등속도 운동 근사해 조사)

  • Kang, Hoon;Kim, Dae-ji;Song, Changheon;Oh, Joo-Young;Cho, Jung-Woo
    • Tunnel and Underground Space
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    • v.30 no.3
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    • pp.181-192
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    • 2020
  • Pin-on-disk test is a suggested abrasion testing method by ASTM (American Society for Testing and Materials). This briefly illustrated the Archimedean spiral motion of a pin type specimen on a disk. To apply this method to rock cutting tools, a constant linear velocity (CLV) is precisely maintained during the test. We defined the two velocity vectors (RPM and horizontal speed) which connected to the resultatnt velocity. We derived a differential equations for the two parameters under CLV condition. It was difficult to find a exact solution. Previous literatures had been reviewed, and an approximate solution was investigated. We mathematically simulated the result for a certain parameter, and examine the accuracy of the solution.

Uniaxial Compression Behavior of Circular RC Columns Confined by Carbon Fiber Sheet Wraps (탄소섬유시트로 구속된 원형 RC기둥의 일축압축 거동)

  • Han, Sang Hoon;Hong, Ki Nam
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.2
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    • pp.125-133
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    • 2007
  • External confinement by CFS (Carbon Fiber Sheet) is a very effective retrofit method for the reinforced concrete columns subject to either static or seismic loads. For the reliable and cost-effective design of CFS, an accurate stress-strain curve is required for CFS-confined concrete. In this paper, uniaxial compression test on short RC column with circular section was performed. To evaluate the effect of confinement on the stress-strain relationship of CFS-confined concrete, CFS area ratio, spiral area ratio, and concrete compressive strength are considered as the test variables. Experiment results indicate that CFS jacketing significantly enhances strength and ductility of concrete. In addition, the CFS-jacketed specimens with the spiral steel show the lower load increasement ratio than those without the spiral steel.

Study on Performance Characteristics of Spiral Fin-Tube Evaporator Applied to Domestic Refrigerator-Freezers (나선형 핀-튜브 증발기를 적용한 냉장고의 성능 특성에 관한 연구)

  • Lee, Sang Hun;Yoon, Won Jae;Kim, Yongchan;Lee, Mooyeon;Yun, Seongjung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.3
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    • pp.205-212
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    • 2013
  • The objective of this study was to investigate the feasibility of replacing a conventional plate fin-tube evaporator with a spiral fin-tube evaporator by comparing the performance of domestic refrigerator-freezers adopting either the plate fin-tube evaporator or spiral fin-tube evaporator. Experiments were conducted for the domestic refrigerator-freezers using either a 2-column and 15-row plate fin-tube evaporator or three spiral fin-tube evaporators with 11, 13, and 15 tube rows (N). The optimum refrigerant charge decreased with a decrease in the number of tube rows. The power consumptions of the domestic refrigerator-freezers using the spiral fin-tube evaporators with N = 11 and 13 were 2.8% and 1.5% lower than those using the plate fin-tube evaporator, respectively. In addition, the cooling capacity of the spiral fin-tube evaporator with N = 13 was 3%-7% higher than that of the plate fin-tube evaporator under the frosting condition. In a cooling speed test, all of the evaporators showed similar performances.

Research on anti-seismic property of new end plate bolt connections - Wave web girder-column joint

  • Jiang, Haotian;Li, Qingning;Yan, Lei;Han, Chun;Lu, Wei;Jiang, Weishan
    • Steel and Composite Structures
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    • v.22 no.1
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    • pp.45-61
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    • 2016
  • The domestic and foreign scholars conducted many studies on mechanical properties of wave web steel beam and high-strength spiral stirrups confined concrete columns. Based on the previous research work, studies were conducted on the anti-seismic property of the end plate bolt connected wave web steel beam and high-strength spiral stirrups confined concrete column nodes applied with pre-tightening force. Four full-size node test models in two groups were designed for low-cycle repeated loading quasi-static test. Through observation of the stress, distortion, failure process and failure mode of node models, analysis was made on its load-carrying capacity, deformation performance and energy dissipation capacity, and the reliability of the new node was verified. The results showed that: under action of the beam-end stiffener, the plastic hinges on the end of wave web steel beam are displaced outward and played its role of energy dissipation capacity. The study results provided reliable theoretical basis for the engineering application of the new types of nodes.

Development and Application of an Open Water Test System for Azimuth Thrusters (아지무스 추진기 단독시험 시스템 개발 및 적용)

  • Lee, Young-Jin;Rhyu, Seong-Sun;Seo, Jong-Soo;Lew, Jae-Moon
    • Journal of the Society of Naval Architects of Korea
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    • v.50 no.4
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    • pp.199-205
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    • 2013
  • To research and develop an azimuth thruster, the new type of open water test dynamometers to measure thrust, torque, total thrust and duct force are designed and manufactured by Samsung Ship Model Basin(SSMB). A compact servomotor to be accurately controlled is connected to precise spiral bevel gear through shafting system combined by couplings and main shafts. The dynamometers have shown excellent linearity and repeatability for all components of forces and a torque. Also, the open water tests have been successfully performed to show the performance of the system. In near future, it is expected that the device can be used for the study of scale effects and development of azimuth thrusters.

Evaluation of Wear Characteristics on Ti/Cr PVD Coatings of Cold Press Die for the Forming of UHSS (초고장력강판 성형용 냉간 프레스 금형의 Ti/Cr계 PVD코팅에 대한 마모 특성 평가)

  • Heo, J.Y.;Youn, K.T.;Song, J.S.;Kang, I.S.;Yoon, I.C.;Park, C.D.
    • Transactions of Materials Processing
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    • v.31 no.4
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    • pp.186-193
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    • 2022
  • The application of UHSS sheet is being expanded up to 50% to reduce the weight of automobiles and improve safety. However, due to the high strength and low elongation of the ultra-high tensile strength steel sheet, product defects such as spring back and mold defects such as cracks and chippings also occur. In this study, Pin/Ring on Disc and Spiral wear tests were conducted to evaluate the durability of Ti/Cr-coated molds for forming 1.2GPa grade UHSS sheets. Component analysis and thickness were measured for each coating layer, and hardness and adhesion were investigated to determine mechanical properties. Combining the results of various wear tests, it was found that the TiAlN coating had the best wear and sticking resistance.

A Study on the Fine Particle Dispensing Conditions for a Spiral Surface of Round Aluminum Bars (알루미늄 환봉의 나선형 표면 미세입자 분사가공의 조건에 대한 연구)

  • Choi, Sung-Yun;Lee, Eun-Ju;Lee, Sea-Han;Kwon, Dae-Gyu
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.8
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    • pp.88-93
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    • 2020
  • The goal of this study is to determine the influence of major factors on the spiral surface microparticle injection machining of cylindrical specimens by the statistical method ANOVA. Before the experiment, rod-shaped test specimens and jigs for helical surface spraying were prepared, and the surface roughness was measured with a surface roughness meter. The injection particle, nozzle diameter, and injection pressure were the primary parameters of the experiment. Other factors that were considered were injection height, injection time, revolutions, and feed distance. The surface roughness after machining was measured, and the effects of the surface roughness data on the primary factors were determined with ANOVA.

Experimental Study on Behavior of Confined Concrete According to Configuration of High-Strength Transverse Reinforcement (고강도 횡보강근의 배근형상에 따른 콘크리트의 거동에 관한 실험적 연구)

  • Kim, Young Seek;Kim, Dong Hwan;Kim, Sang Woo;Kim, Kil Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.6
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    • pp.1-8
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    • 2012
  • This study estimates the performance of confined concrete according to the configuration of transverse steel bars. The main test variables were the yield strength of spiral reinforcement and configuration of transverse reinforcement. A total of 27 specimens with rectangular cross section were cast and tested under monotonic concentric compression. R-type specimens with rectangular spirals, C-type specimens with circular spirals and O-type specimens with combined shape of rectangular and octagon were designed in this study. From experimental results, it is concluded that the proposed configuration of transverse reinforcement can provided improved ductility to the confined concrete compared to rectangular spiral reinforcement.

The immediate effects of spiral taping on improvement of gait ability in patients with chronic stroke (나선형 테이핑 적용이 만성 뇌졸중 환자의 보행능력 개선에 미치는 즉각적인 효과)

  • Kim, Dong-Dae;Park, Shin-Jun
    • Journal of Digital Convergence
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    • v.15 no.4
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    • pp.529-536
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    • 2017
  • The purpose of this study is to examine the immediate effects of spiral taping applied to an affected leg on gait ability in stroke patients. Forty two stroke patients were divided into a spiral taping group (n=21) and a quadriceps femoris group (n=21), and each taping method was applied. Spatiotemporal Gait Parameters (Cadence, speed, gait cycle duration, stance phase duration, double support duration) were measured using the 10-meter walk test, the dynamic gait index (DGI) and an accelerometer for both groups. Both groups showed a significant increase in a 10-minute walk, the DGI, cadence, speed before and after the intervention, whereas no significant difference was detected in stance phase duration, gait cycle duration and double support duration on the affected side in all groups. All groups revealed no significant difference in variation. It has been found that the two taping methods augment gait ability in patients with stroke. This study suggests that spiral taping can be an easily applicable method at home.