• Title/Summary/Keyword: Full-scale testing

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Numerical and experimental study of the nested-eccentric-cylindrical shells damper

  • Reisi, Alireza;Mirdamadi, Hamid Reza;Rahgozar, Mohammad Ali
    • Earthquakes and Structures
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    • v.18 no.5
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    • pp.637-648
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    • 2020
  • In this study, a new steel cylindrical shell configuration of the dissipative energy device is proposed to improve lateral ductility and to reduce the damage of the structures against seismic forces. Four nested-eccentric- cylindrical shells are used to constructing this device; therefore, this proposed device is named nested-eccentric-cylindrical shells damper (NECSD). The particular configuration of the nested-eccentric-cylindrical shells is applied to promote the mechanical characteristics, stability, and overall performance of the damper in cyclic loads. Shell-type components are performed as a combination of series and parallel non-linear springs into the in-plan plastic deformation. Numerical analysis with respect to dimensional variables are used to calculate the mechanical characteristics of the NECSD, and full-scale testing is conducted for verifying the numerical results. The parametric study shows the NECSD with thin shells were more flexible, while devices with thick shells were more capacious. The results from numerical and experimental studies indicate that the NECSD has a stable behavior in hysteretic loops with highly ductile performance, and can provide appropriate dissipated energy under cyclic loads.

Wind Tunnel Test of an Unmanned Aerial Vehicle (UAV)

  • Chung, Jin-Deog;Lee, Jang-Yeon;Sung, Bong-Zoo;Koo, Sa-Mok
    • Journal of Mechanical Science and Technology
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    • v.17 no.5
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    • pp.776-783
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    • 2003
  • A low speed wind tunnel test was conducted for full-scale model of an unmanned aerial vehicle (UAV) in Korea Aerospace Research Institute (KARI) Low Speed Wind Tunnel(LSWT). The purpose of the presented paper is to illustrate the general aerodynamic and performance characteristics of the UAV that was designed and fabricated in KARI. Since the testing conditions were represented minor portions of the load-range of the external balance system, the repeatability tests were performed at various model configurations to confirm the reliability of measurements. Variations of drag-polar by adding model components such as tails, landing gear and test boom are shown, and longitudinal and lateral aerodynamic characteristics after changing control surfaces such as aileron, flap, elevator and rudder are also presented. To explore aerodynamic characteristics of an UAV with model components build-up and control surface deflections, lift curve slope, pitching moment variation with lift coefficients and drag-polar are examined. The discussed results might be useful to understand the general aerodynamic characteristics and drag pattern for the given UAV configuration.

A Study on the Physical Properties of Recycled Asphalt Mixtures Using Glass Fiber Reinforcement (유리섬유 보강재를 이용한 재활용 아스팔트 혼합물의 물리적 특성에 관한 연구)

  • Park, Ki Soo;Yoo, Pyeong Jun
    • International Journal of Highway Engineering
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    • v.20 no.4
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    • pp.27-34
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    • 2018
  • PURPOSES : The objective of this study is to evaluate the physical properties of recycled asphalt mixtures reinforced with glass fiber. METHODS : Firstly, mixing design was conducted on recycled asphalt mixture for use of 50% recycled aggregate. Various laboratory tests were performed on four types of recycled asphalt mixtures with different glass fiber content to evaluate the physical properties. The laboratory tests include indirect tensile strength test, dynamic modulus test, Hamburg wheel tracking test and tensile-strength ratio to evaluate cracks, rutting and moisture resistance of mixtures. RESULTS : The indirect tensile strength of fiber reinforced glass increased about 139.4%. As a result of comparing the master curves obtained by the dynamic modulus test, the elasticity was low in the low temperature region and high in the high temperature region when the glass fiber was reinforced. The glass fiber contents of PEGS 0.3%, Micro PPGF 0.1% and Macro PPGF 0.3% showed the highest moisture resistance and rutting resistance. CONCLUSIONS : The test results show that use of glass fiber reinforcement can increase the resistance to cracking, rutting, and moisture damage of asphalt mixtures. It is also necessary to validate the long-term performance of recycled asphalt mixtures with glass fiber using full scale pavement testing and field trial construction.

Prequalification of a set of buckling restrained braces: Part I - experimental tests

  • Stratan, Aurel;Zub, Ciprian Ionut;Dubina, Dan
    • Steel and Composite Structures
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    • v.34 no.4
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    • pp.547-559
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    • 2020
  • Buckling restrained braces (BRBs) were developed as an enhanced alternative to conventional braces by restraining their global buckling, thus allowing development of a stable quasi-symmetric hysteretic response. A wider adoption of buckling restrained braced frames is precluded due to proprietary character of most BRBs and the code requirement for experimental qualification. To overcome these problems, BRBs with capacities corresponding to typical steel multi-storey buildings in Romania were developed and experimentally tested in view of prequalification. The first part of this paper presents the results of the experimental program which included sub-assemblage tests on ten full-scale BRBs and uniaxial tests on components materials (steel and concrete). Two different solutions of the core were investigated: milled from a plate and fabricated from a square steel profile. The strength of the buckling restraining mechanism was also investigated. The influence of gravity loading on the unsymmetrical deformations in the two plastic segments of the core was assessed, and the response of the bolted connections was evaluated. The cyclic response of BRBs was evaluated with respect to a set of performance parameters, and recommendations for design were given.

Performance assessment of advanced hollow RC bridge column sections

  • Kim, T.H.;Kim, H.Y.;Lee, S.H.;Lee, J.H.;Shin, H.M.
    • Computers and Concrete
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    • v.16 no.5
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    • pp.703-722
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    • 2015
  • This study investigates the performance of advanced hollow reinforced concrete (RC) bridge column sections with triangular reinforcement details. Hollow column sections are based on economic considerations of cost savings associated with reduced material and design moments, as against increased construction complexity, and hence increased labor costs. The proposed innovative reinforcement details are economically feasible and rational, and facilitate shorter construction periods. We tested a model of advanced hollow column sections under quasi-static monotonic loading. The results showed that the proposed triangular reinforcement details were equal to the existing reinforcement details, in terms of the required performance. We used a computer program, Reinforced Concrete Analysis in Higher Evaluation System Technology (RCAHEST), for analysis of the RC structures; and adopted a modified lateral confining effect model for the advanced hollow bridge column sections. Our study documents the testing of hollow RC bridge column sections with innovative reinforcement details, and presents conclusions based on the experimental and analytical findings. Additional full-scale experimental research is needed to refine and confirm the design details, especially for the actual detailing employed in the field.

Assignment of the Allowable Design Values for Domestic Softwood Structural Lumber - Structural I-grade - (국산 침엽수구조재의 허용응력설정에 관하여 - 1종 구조재를 중심으로 -)

  • Oh, Sei-Chang
    • Journal of the Korean Wood Science and Technology
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    • v.24 no.1
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    • pp.11-16
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    • 1996
  • The purpose of this paper is to present a summary of assignment design values according to domestic softwood structural lumber grading rules. Allowable stresses for visually graded lumber were determined from basic data on small. clear specimens. The data corrected for variability such as natural defects and other factors. The procedure adopted by Japan was used for assigning allowable design values. Strength ratios in relation to each defect were taken from ASTM D 245-81. Korean pine(Pinus koraiensis S. et Z.), Korean red pine(Pinus densiflora S. et Z.), Japanese larch(Larix leptolepis Gordon) and Needle fir(Abies holophylla Max) were applied to this study. The calculated allowable stresses were same in Korean pine and Korean red pine. These values were highest in Japanese larch lowest in Needle fir. So, it is desirable for these species to be classified into different catagories Species Group. However, accurate comparison in design values on lumber grading rules among U.S., Japan and Korea was somewhat difficult. And full scale testing will be necessary for accurate determination of the correction factors to setting up design values.

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A model for evaluating the fire resistance of contour-protected steel columns

  • Kodur, V.K.R.;Ghani, B.A.;Sultan, M.A.;Lie, T.T.;El-Shayeb, M.
    • Structural Engineering and Mechanics
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    • v.12 no.5
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    • pp.559-572
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    • 2001
  • A numerical model, in the form of a computer program, for evaluating the fire resistance of insulated wide-flange steel columns is presented. The three stages associated with the thermal and structural analysis in the calculation of fire resistance of columns is explained. The use of the computer program for tracing the response of an insulated steel column from the initial pre-loading stage to collapse, due to fire, is demonstrated. The validity of the numerical model used in the program is established by comparing the predictions from the computer program with results from full-scale fire tests. Details of fire tests carried out on wide-flange steel columns protected with ceramic fibre insulation, together with results, are presented. The computer program can be used to evaluate the fire resistance of protected wide-flange steel columns for any value of the significant parameters, such as load, section dimensions, column length, type of insulation, and thickness of insulation without the necessity of testing.

Realization Software Development of Road Profile for Multi-axial Road Simulator (다축 로드 시뮬레이터의 노면 프로파일 재현 소프트웨어 개발)

  • 정상화;류신호;김우영;양성모;김택현
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.190-198
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    • 2002
  • Full scale durability test in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, hydraulic road simulator is used to carry out the fatigue test and the vibration test. In this paper, the algorithm and software to realize the real road profile are developed. The operation software for simultaneously controlled multi-axial road simulator is developed and the input and output data are displayed window based PC controller in the real time. Futhermore, the software to generate the real road profile are developed. The validity of the software are verified by applying the belgian road, the city road, the highway, and the gravel road. The results of the above experiment show that the real road profiles are realized well after 10th iteration.

The Design, Manufacture and Applications of a Gap Noise Generator for Testing the Characteristics of EMI from Transmission Lines (송전선로 EMI 특성 실험용 인공잡음발생장치 설계, 제작 및 적용)

  • Ju, Yun-Ro;Yang, Gwang-Ho;Myeong, Seong-Ho;Lee, Dong-Il;Sin, Gu-Yong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.1
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    • pp.23-28
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    • 2002
  • In order to survey the radiation characteristics of pure line noise of unwanted noise from overhead high voltage AC transmission lines, a disk type gap noise generator was manufactured. Disk size which decides capacitance between the noise generator and earth was selected through preliminary indoor experiments and analysis by using surface charge method. The capacitance is one of principal parameters related to the injection of a proper noise current into lines. On the basis of the capacitance obtained from calculation, 5mm of space was given to the gap of the noise generator to be installed o test line and an aluminum disk of 60cm radius was made. The field experiments were performed with the noise generator hung on the Kochang 765 kV full scale test line. As the results, the useful data which can be used to analysis the radiation characteristics of noise from transmission lines were obtained. Those are the directivity of antenna toward the line, lateral profiles, frequency spectra, height pattern and so on.

Developments in Fire Sprinkler Technology

  • Rice, Douglas
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.606-609
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    • 1997
  • Technology in fire sprinklers has exploded. There is more private fire sprinkler research now than ever before. New technology in fire sprinklers has tested the existing standard and found that it was wrong in some cases, it has provided new sprinklers that control fire better while reducing the cost of the overall system. This expansion of the types and applications of fire sprinklers has created a great need for education for the Authorities Having Jurisdiction and the Engineer as they must be able to make informed decisions regarding this new technology. Significant research has been done at Factory Mutual Research Corporation and Underwriters Laboratory in the United States. Full scale fire testing is done to prove any new technology did not lower the level of protection of existing fire sprinkler system installations. In each and every case, the existing level of fire protection was the baseline against which the new sprinklers were tested. This level can not be lowered for the test to be considered a success. This is intended to be an overview of the developments in fire sprinklers. Although extensive detail is not included, the overall aspects of these developments can be discussed. The research that will be covered will include the following general subjects: high piled and rack storage sprinkler protection without in-rack sprinklers, extended coverage and quick response sprinklers for ordinary and light hazard occupancies, as well as special sprinklers and their applications.

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