• Title/Summary/Keyword: real scale experimental

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Experimental investigation of the behaviour of a steel sub-frame under a natural fire

  • Santiago, Aldina;Simoes da Silva, Luis;Vaz, Gilberto;Vila Real, Paulo;Lopes, Antonio Gameiro
    • Steel and Composite Structures
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    • v.8 no.3
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    • pp.243-264
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    • 2008
  • This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

A Study on the Frequency Scaling Methods Using LSP Parameters Distribution Characteristics (LSP 파라미터 분포특성을 이용한 주파수대역 조절법에 관한 연구)

  • 민소연;배명진
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.3
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    • pp.304-309
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    • 2002
  • We propose the computation reduction method of real root method that is mainly used in the CELP (Code Excited Linear Prediction) vocoder. The real root method is that if polynomial equations have the real roots, we are able to find those and transform them into LSP. However, this method takes much time to compute, because the root searching is processed sequentially in frequency region. In this paper, to reduce the computation time of real root, we compare the real root method with two methods. In first method, we use the mal scale of searching frequency region that is linear below 1 kHz and logarithmic above. In second method, The searching frequency region and searching interval are ordered by each coefficient's distribution. In order to compare real root method with proposed methods, we measured the following two. First, we compared the position of transformed LSP (Line Spectrum Pairs) parameters in the proposed methods with these of real root method. Second, we measured how long computation time is reduced. The experimental results of both methods that the searching time was reduced by about 47% in average without the change of LSP parameters.

Experimental analysis of a semi-actively controlled steel building

  • Occhiuzzi, Antonio;Spizzuoco, Mariacristina
    • Structural Engineering and Mechanics
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    • v.19 no.6
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    • pp.721-747
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    • 2005
  • The strong need of verifying theories formulated for semi-active control through applications to real structures is due to the fact that theoretical research on semi-active control systems is not matched by a corresponding satisfactory experimental activity. This paper shows how a smart system including magnetorheological devices as damping elements can be implemented in a large-scale structural model, by describing in detail the kind of electronics (dedicated hardware and software) adopted during the experimental campaign. It also describes the most interesting results in terms of reduction of the seismic response (either experimental or numerical) of the semi-actively controlled structure compared to a passive operating control system, and in terms of the evaluation criteria proposed in the benchmark for seismically excited controlled buildings. The paper also explains how to derive from the classical theory of optimal control the adopted control logic, based on a clear physical approach, and provides an exhaustive picture of the time delays characterizing the control sequence.

A study on experiment methods and effectiveness of the current collection study using the speed scale-downed catenary-pantograph model (속도 축척 모형 실험 방법을 통한 집전계 성능 분석 연구의 실험 방법 및 효용성에 대한 연구)

  • Park, Sa-Hoon;Kwon, Sam-Young
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.874-882
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    • 2008
  • To test the current collection characteristics between overhead contact lines and pantograph in a real speed scale costs too much, therefore, it is very difficult to be realized especially in a high speed region. As a alternative, the speed scale-downed tests is proposed. In this paper, the experimental methodology and effectiveness of the speed scale-downed tests are discussed through the dynamic simulation evaluations. To get a more precise test results to the real speed scale test in the 1/2 and 1/4 speed scale-downed tests, various experimental conditions are discussed. Throughout the simulation in a various conditions the effectiveness are evaluated.

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Verification of Real-time Hybrid Test System using RC Pier Model (RC교각을 이용한 실시간 하이브리드 실험 시스템의 적용성 연구)

  • Lee, Jinhaeng;Park, Minseok;Chae, Yunbyeong;Kim, Chul-Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.4
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    • pp.253-259
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    • 2018
  • Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.

Fracture Mechanics Study on Wear Mechanism of Ceramics -Discussions on Experimental Results of Wear Test- (세라믹의 마멸기구에 관한 파괴역학적 연구 -마멸실험 결과의 고찰-)

  • 김석삼;김재호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.3
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    • pp.636-645
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    • 1990
  • Analytically induced wear mechanism of elastic body under Hertzian contact is applied in acutual wear test of ceramics. There are two types of wear in ceramics, a large scale wear and a small scale wear. The large scale wear is commensurable with Hertzian contact area and the small scale wear with real contact area. Nondimensional parameter, S$_{c}$, is introduced and fully examined to estimate or predict wear rate of ceramics. Ceramic wear for S$_{c}$.leq.0.8 is in small scale wear and for S$_{c}$;geq.1.6 in large scale wear. wear.

Performance Evaluation of a Large-scale MR Damper for Controlling Seismic Response using a Real-time Hybrid Test Method (실시간 하이브리드 실험법을 이용한 대형 MR감쇠기의 제진 성능평가)

  • Chung, Hee-San;Lee, Sung-Kyung;Park, Eun-Churn;Youn, Kyung-Jo;Min, Kyung-Won;Lee, Heon-Jae;Choi, Kang-Min;Moon, Suk-Jun;Jung, Hyung-Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.655-660
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    • 2007
  • This paper presents real-time hybrid test method of large-scale MR damper applied to a building structure under seismic excitation. The real-time hybrid test using an actuator for the control performance evaluation of a MR damper controlling the response of earthquake-excited building structure is experimentally implemented. In the test, the building structure is used as a numerical part, on which a large-scale MR damper adopted as an experimental part was installed to reduce its response. At first, the force that is acting between a MR damper and building structure is measured from the load cell attached on the actuator system and is fed-back to the computer to control the motion of the actuator. Then, the actuator is so driven that the error between the interface displacement computed from the numerical building structure with the excitations of earthquake and the fed-back interface force and that measured from the actuator. The control efficiency of the MR damper used in this paper is experimentally confirmed by implementing this process of experiment on real-time.

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Performance Evaluation of a Large-scale MR Damper for Controlling Seismic Responses Using a Real-time Hybrid Test Method (실시간 하이브리드 실험법을 이용한 대형 MR감쇠기의 제진 성능평가)

  • Park, Eun-Churn;Lee, Sung-Kyung;Youn, Kyung-Jo;Chung, Hee-San;Lee, Heon-Jae;Choi, Kang-Min;Moon, Suk-Jun;Jung, Hyung-Jo;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.1
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    • pp.131-138
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    • 2008
  • This paper presents real-time hybrid test method of large-scale MR damper applied to a building structure under seismic excitation. The real-time hybrid test using an actuator for the control performance evaluation of a MR damper controlling the response of earthquake-excited building structure is experimentally implemented. In the test, the building structure is used as a numerical part, on which a large-scale MR damper adopted as an experimental part was installed to reduce its response. At first, the force that is acting between a MR damper and building structure is measured from the load cell attached on the actuator system and is fed-back to the computer to control the motion of the actuator. Then, the actuator is so driven that the error between the interface displacement computed from the numerical building structure with the excitations of earthquake and the fed-back interface force and that measured from the actuator. The control efficiency of the MR damper used in this paper is experimentally confirmed by implementing this process of experiment on real-time.

An Experimental Study on the Warehouse Mock-up Fire Test (창고 모델 실물화재 특성에 대한 실험적 연구)

  • Kweon, Oh-Sang;Yoo, Yong-Ho;Kim, Heung-Youl
    • Fire Science and Engineering
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    • v.24 no.4
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    • pp.47-54
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    • 2010
  • This study is analyze the damage of warehouse fire accident be made through the fire characteristic database of combustibles and real scale fire test of warehouse mock-up. Combustibles fire tests are carried out for database using RCT (Room Corner Tester) to predict fire growth the goods. A mockup ($3m{\times}3m{\times}2.4m$) of clothes warehouse was built and real scale fire test by LSC (Large Scale Calorimeter) base on the fire characteristic DB. The mock-up of clothes warehouse is made of two type sandwich panels (Glass wool, EPS foam sandwich panel). As a mock-up test result, test 1 (Glass wool sandwich panel) and test 2 (EPS foam sandwich panel) indicating fire growth such as 5 MW, 11 MW of maximum HRR (Heat Release Rate).

A Basic Study of Fuel 2-staging Y-jet Atomizer to Reduce NOx in Liquid Fuel Burner (액체 연료용 버너에서 NOx 저감을 위한 연료2단 분사 Y-jet 노즐에 관한 기초연구)

  • Song, Si-Hong;Lee, Gi-Pung;Kim, Hyeok-Je;Park, Seok-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.11
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    • pp.1616-1623
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    • 2001
  • A basic experimental study has been carried out to find out the design parameters of fuel 2-staging atomizers in order to reduce nitrogen oxides(NOx) rate emitted from the steam boilers used the liquid fuel. The heavy fuel oil(B-Coil) and fuel 2-staging Y-jet twin-fluid atomizers were adopted in this study. The results of this paper were obtained from the real as well as the model scale atomizers. In the case of model atomizers test, NOx reduction rate was strongly dependent on the staged fuel rate, but it was weakly dependent on the injection hole arrangement and air swirl conditions. The real scale atomizers was designed and manufactured on the base of these test results, and those was mounted and operated in the real boiler generates 185 ton steam per an hour. The reduction rate of the model and real plant was reached 10∼30% of base NOx by atomizers. but dust was sharply increased in the low O$_2$combustion region of the real plant.