• Title/Summary/Keyword: Quasi Static Test

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Stiffness Reduction Factor for Flat Plate Slabs (플랫 플레이트 슬래브 해석을 위한 강성감소계수 제안)

  • Park, Young-Mi;Han, Sang-Whan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.337-340
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    • 2006
  • The purpose of this study is to propose the stiffness reduction factor for flat plate slabs under lateral loads. Current design code (e.g., ACI 318-05) requires considering the effects of cracks for calculating slab stiffness under lateral loads. This study collected the test results of 20 interior slab-column connections, from which stiffness reduction in each test was estimated with respect to the ratio of applied moment to cracking moment ($M_a/M_{cr}$). Based on collected data, this study proposed equations for calculating stiffness reduction with respect to $M_a/M_{cr}$. To verify the proposed equations, this study conducted the experimental test of interior slab-column connections under quasi-static cyclic loading. From the test, load-deformation curve is compared to that obtained from effective beam width method with the proposed equation for the stiffness reduction. It is shown that the effective beam width method with the proposed equation for stiffness reduction predicts accurately the test results.

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Launch Environment Requirements for Earth Observation Satellite (지구관측위성의 발사환경시험 요구조건)

  • Kim, Kyung-Won;Kim, Sung-Hoon;Kim, Jin-Hee;Rhee, Ju-Hun;Hwang, Do-Soon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.747-750
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    • 2004
  • After launching, spacecraft is exposed to extreme environments. So spacecraft should be tested after design/manufacture to verify whether components can be operated functionally. Acceleration transferred from launch vehicle to spacecraft produces quasi-static load, sine vibration and random vibration. Random vibration is also induced by acoustic vibrations transferred by surface of spacecraft. And shock vibration is produced when spacecraft is separated from launch vehicle. To verify operation of spacecraft under these launch environments, separation shock test, sine vibration test, acoustic vibration test and random vibration test should be performed. This paper describes these launch environment test requirements.

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Dynamic buckling analysis of a composite stiffened cylindrical shell

  • Patel, S.N.;Bisagni, C.;Datta, P.K.
    • Structural Engineering and Mechanics
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    • v.37 no.5
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    • pp.509-527
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    • 2011
  • The paper investigates the dynamic buckling behaviour of a laminated composite stiffened cylindrical shell using the commercial finite element code ABAQUS. The numerical model of the composite shell is validated by static tests. In particular, the experimental collapse test is numerically simulated by a quasi static analysis carried out by both ABAQUS/Standard and ABAQUS/Explicit. The behaviour in the post-buckling field and the collapse load obtained by the analyses are close to the experimental data. The validated model is then used to study the dynamic buckling behaviour with ABAQUS/Explicit. The effects of the loading magnitude and of the loading duration are investigated, implementing in the analysis also first-ply failure criteria. It is observed that the dynamic buckling load is highly affected by the loading duration.

Axial Impact Collapse Analysis of Spot Welded Hat Shaped Section Members

  • Yang, In-Young;Cha, Cheon-Seok;Kang, Jong-Yup
    • Journal of Mechanical Science and Technology
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    • v.15 no.2
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    • pp.180-191
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    • 2001
  • The widely used spot welded sections of automobiles(hat and double hat shaped section members) absorb most of the energy in a front-end collision. The sections were tested with respect to axial static(10mm/min) and quasi-static(1000mm/min) loads. Based on these test results, specimens with various thicknesses, width ratios and spot weld pitches on the flange were tested at high impact velocity(7.19m/sec and 7.94m/sec) which simulates an actual car crash. Characteristics of collapse have been reviewed and structures for optimal energy absorbing capacity is suggested.

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Comparison of the Fatigue Behaviors of FRP Bridge Decks and Reinforced Concrete Conventional Decks Under Extreme Environmental Conditions

  • Kwon, Soon-Chul;Piyush K. Dutta;Kim, Yun-Hae;Anido, Roberto-Lopez
    • Journal of Mechanical Science and Technology
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    • v.17 no.1
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    • pp.1-10
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    • 2003
  • This paper summarizes the results of the fatigue test of four composite bridge decks in extreme temperatures (-30$^{\circ}C$ and 50$^{\circ}C$ ). The work was performed as part of a research program to evaluate and install multiple FRP bridge deck systems in Dayton, Ohio. A two-span continuous concrete deck was also built on three steel girders for the benchmark tests. Simulated wheel loads were applied simultaneously at two points by two servo-controlled hydraulic actuators specially designed and fabricated to perform under extreme temperatures. Each deck was initially subjected to one million wheel load cycles at low temperature and another one million cycles at high temperature. The results presented in this paper correspond to the fatigue response of each deck for four million load cycles at low temperature and another four million cycles at high temperature. Thus, the deck was subjected to a total of ten million cycles. Quasi-static load-deflection and load-strain responses were determined at predetermined fatigue cycle levels. Except for the progressive reduction in stiffness, no significant distress was observed in any of the composite deck prototypes during ten million load cycles. The effects of extreme temperatures and accumulated load cycles on the load-deflection and load-strain response of FRP composite and FRP-concrete hybrid bridge decks are discussed based on the experimental results.

Fatigue Analysis of Rear Suspension Part Applying Multi-body Dynamics (다물체 동역학을 이용한 후륜 현가 부품의 내구해석)

  • Jeon, Seong Min;Cho, Byung-Kwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.10
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    • pp.1039-1044
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    • 2015
  • During the development of vehicles, durability tests are time consuming and costly. Recently, automobile companies have attempted to develop their own durability evaluation procedures by modifying and complementing . In this paper, we propose an integrated computer-aided engineering (CAE) method to evaluate the durability of a torsion beam axle (TBA). We compare this method with the standardized durability evaluation method used by an actual automobile company in order to determine the feasibility of this method. We compare the results with the test result data to enable us to estimate the reliability of the analysis results. In this study, we analyze the processes and results of the quasi-static fatigue analysis, and found improved methods and problems. Furthermore, we perform a thorough test using the requirements of the actual company. Based on the results, the structural analysis process in the quasi-static fatigue analysis method was superseded by the multi-body dynamics analysis process. Generally, this method is referred to as the resonance-fatigue analysis method.

Experimental and numerical investigation of the seismic performance of railway piers with increasing longitudinal steel in plastic hinge area

  • Lu, Jinhua;Chen, Xingchong;Ding, Mingbo;Zhang, Xiyin;Liu, Zhengnan;Yuan, Hao
    • Earthquakes and Structures
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    • v.17 no.6
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    • pp.545-556
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    • 2019
  • Bridge piers with bending failure mode are seriously damaged only in the area of plastic hinge length in earthquakes. For this situation, a modified method for the layout of longitudinal reinforcement is presented, i.e., the number of longitudinal reinforcement is increased in the area of plastic hinge length at the bottom of piers. The quasi-static test of three scaled model piers is carried out to investigate the local longitudinal reinforcement at the bottom of the pier on the seismic performance of the pier. One of the piers is modified by increased longitudinal reinforcement at the bottom of the pier and the other two are comparative piers. The results show that the pier failure with increased longitudinal bars at the bottom is mainly concentrated at the bottom of the pier, and the vulnerable position does not transfer. The hysteretic loop curve of the pier is fuller. The bearing capacity and energy dissipation capacity is obviously improved. The bond-slip displacement between steel bar and concrete decreases slightly. The finite element simulations have been carried out by using ANSYS, and the results indicate that the seismic performance of piers with only increasing the number of steel bars (less than65%) in the plastic hinge zone can be basically equivalent to that of piers that the number of steel bars in all sections is the same as that in plastic hinge zone.

Quasi-Static and Shaking Table Tests of Precast Concrete Structures Utilizing Clamped Mechanical Splice (가압고정 기계적이음을 활용한 프리캐스트 콘크리트 구조물의 준정적 및 진동대 실험)

  • Sung, Han Suk;Ahn, Seong Ryong;Park, Si Young;Kang, Thomas H.-K.
    • Journal of the Earthquake Engineering Society of Korea
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    • v.27 no.1
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    • pp.37-47
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    • 2023
  • A new clamped mechanical splice system was proposed to develop structural performance and constructability for precast concrete connections. The proposed mechanical splice resists external loading immediately after the engagement. The mechanical splices applicable for both large-scale rebars for plants and small-scale rebars for buildings were developed with the same design concept. Quasi-static lateral cyclic loading tests were conducted with reinforced and precast concrete members to verify the seismic performance. Also, shaking table tests with three types of seismic wave excitation, 1) random wave with white noise, 2) the 2016 Gyeongju earthquake, and 3) the 1999 Chi-Chi earthquake, were conducted to confirm the dynamic performance. All tests were performed with real-scale concrete specimens. Sensors measured the lateral load, acceleration, displacement, crack pattern, and secant system stiffness, and energy dissipation was determined by lateral load-displacement relation. As a result, the precast specimen provided the emulative performance with RC. In the shaking table tests, PC frames' maximum acceleration and displacement response were amplified 1.57 - 2.85 and 2.20 - 2.92 times compared to the ground motions. The precast specimens utilizing clamped mechanical splice showed ductile behavior with energy dissipation capacity against strong motion earthquakes.

Test for the influence of socket connection structure on the seismic performance of RC prefabricated bridge piers

  • Yan Han;Shicong Ding;Yuxiang Qin;Shilong Zhang
    • Earthquakes and Structures
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    • v.25 no.2
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    • pp.89-97
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    • 2023
  • In order to obtain the impact of socket connection interface forms and socket gap sizes on the seismic performance of reinforced concrete (RC) socket prefabricated bridge piers, quasi-static tests for three socket prefabricated piers with different column-foundation connection interface forms and reserved socket gap sizes, as well as to the corresponding cast-in-situ reinforced concrete piers, were carried out. The influence of socket connection structure on various seismic performance indexes of socket prefabricated piers was studied by comparing and analyzing the hysteresis curve and skeleton curve obtained through the experiment. Results showed that the ultimate failure mode of the socket prefabricated pier with circumferential corrugated treatment at the connection interface was the closest to that of the monolithic pier, the maximum bearing capacity was slightly less than that of the cast-in-situ pier but larger than that of the socket pier with roughened connection interface, and the displacement ductility and accumulated energy consumption capacity were smaller than those of socket piers with roughened connection interface. The connection interface treatment form had less influence on the residual deformation of socket prefabricated bridge piers. With the increase in the reserved socket gap size between the precast pier column and the precast foundation, the bearing capacity of the prefabricated socket bridge pier component, as well as the ductility and residual displacement of the component, would be reduced and had unfavorable effect on the energy dissipation property of the bridge pier component.

Seismic Performance Evaluation of Shear-Critical R/C Bridge Piers Retrofitted with Fiber Sheets (섬유 보강된 휨전단 RC교각의 내전성능 평가)

  • 송호진;정영수;김용곤;이은희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.195-202
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    • 2002
  • Lap splices of longitudinal reinforcement steels were practically located in the potential plastic hinge region of most bridge columns that were constructed before the 1992 seismic design provision of Roadway Bridge Design Specification in Korea. The objective of this research is to evaluate the seismic performance of shear-critical reinforced concrete(RC) bridge piers with poor detailing of the starter bars in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity by retrofitting with fiber composites. Seven test specimens in the aspect ratio of 2.5 were made with three confinement ratios and two types of lap splices. Quasi-static test was conducted in a displacement-controlled test mode. A significant reduction of displacement ductility ratios were observed for test columns with lap splices of longitudinal steels.

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