• Title, Summary, Keyword: 압괴 시험

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On Quasi-Static Crushing of a Stiffened Square Tube (보강된 정사각형 단면 강관의 정적 압괴거동에 관한 연구)

  • Paik, Jeom Kee;Chung, Jang Young;Chun, Min Sung
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.1
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    • pp.109-123
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    • 1996
  • A series of quasi-static crushing tests were carried out on thin-walled square tube specimens with axial and/or circumferential stiffeners including unstiffened specimens. The effective crushing length and mean crushing strength of the test specimens were investigated. Using the equivalent plate thickness approach, a simplified analytical model for predicting the mean crushing strength of stiffened square tubes has been developed.

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Energy Absorption of Collision Post Based on North American CFR Regulations for Railway Vehicles (철도차량의 북미 CFR 법규에 대한 충돌 기둥에너지 흡수에 관한 연구)

  • Kim, Seung-Tech;Jeong, Ji-Ho;Choi, Jeong-Yong;Woo, Kwan-Je
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.8
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    • pp.935-943
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    • 2012
  • In accidents involving the collision of railway vehicles, there is a risk that structural members might penetrate the cab frame of the railway vehicle in the space in which the driver or passengers are seated. To reduce this risk, worldwide, studies on the collision of railway vehicles are underway. In North America, the Code of Federal Regulations (CFR) was revised in 2010 to include crush criteria for a collision and the corner post in an end frame. In this study, a crush analysis and crush test for a collision post and a crash analysis for a rigid cylinder were performed according to the CFR. The analysis and test results were compared and reviewed. This study aims to determine the usefulness of crush analysis for developing various end frames, and to understand the crush and crash characteristics and review the accuracy of the analysis.

A Study on the energy absorption characteristics of GFRP circular tubes fabricated by the filament winding method (필라멘트 와인딩 공법 GFRP 원형 튜브의 에너지 흡수특성에 관한 연구)

  • Kim, Geo-Young;Koo, Jeong-Seo
    • Composites Research
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    • v.22 no.4
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    • pp.1-12
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    • 2009
  • In this paper, quasi-static crushing tests of composite circular tubes under axial compression load are conducted to investigate the energy absorption characteristics. Circular tubes used for this experiment are glass/epoxy (GFRP) composite tubes which are fabricated by the filament winding method. One edge of the composite tube is chamfered to reduce the initial peak load and to prevent catastrophic failure during crushing process. Energy absorption characteristics vary significantly according to the constituent materials, fabrication conditions, tube geometry and test condition. In tube geometry, according as inner diameter increase, unstable crush mode is caused by local buckling of delamination, but control of the fiber orientation should help composite tubes get stable crush mode.

Study on the Axial Crushing Behaviors of UD Kevlar/Epoxy and Carbon-Kevlar/Epoxy Composite Tubes (단방향 케블라/에폭시, 탄소-케블라/에폭시 복합재 튜브의 축방향 압괴 거동에 대한 연구)

  • Kim, Hyung-Uk;Kim, Jung-Seok;Jung, Hyun-Seung;Yoon, Hyuk-Jin;Kwon, Tae-Soo
    • Journal of the Korean Society for Railway
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    • v.13 no.3
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    • pp.271-277
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    • 2010
  • In this paper, a numerical model for a Kevlar/Epoxy and Carbon-Kevlar/Epoxy tube used as an energy absorbing component has been developed and then results have been verified through experiment. The 2D shell element and Chang-Chang failure criterion of LS-DYNA that is commercial explicit FE code was used. Mechanical material properties for the model were obtained by material testing in advance. The numerical results were compared with quasi-static test results under axial compressive loading at 10mm/min. From the results, in the case of the Kevlar/Epoxy tube, load-crushed displacement curves were very close to the experiments and SEA (specific energy absorption) shows a good agreement with experimental one within less than 6%. However, the Carbon-Kevlar/Epoxy tube shows some differences with the experimental results.

Study on Axial Crushing Behaviors of UD Kevlar/Epoxy with Different Trigger Models (트리거 모델에 따른 일방향 케블라/에폭시 복합재 튜브의 축방향 압괴 거동 연구)

  • Kim, Hyung-Uk;Kim, Jung-Seok;Jung, Hyun-Seung;Yoon, Hyuk-Jin;Kwon, Tae-Soo
    • Composites Research
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    • v.23 no.4
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    • pp.28-34
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    • 2010
  • In this paper, in order to develop a realistic trigger model for a unidirectional Kevlar/Epoxy tube, the numerical model has been established and then verified by comparison with the experimental result. To achieve this goal, four different trigger models were candidated and evaluated using the commercial explicit FE code LS-DYNA. In the finite element analysis, the 2D shell element and Chang-Chang failure criterion was used. Mechanical material properties for the model were obtained by material testing in advance. The numerical results were compared with quasi-static test results under axial compressive loading at 10mm/min. The load-crushed displacement curves were very close to the experiments and SEA (specific energy absorption) showed a good agreement with experimental one within less than 5%.

FE Simulation of Axial Crushing Test for AZ31 Tube Considering Tension-Compression Asymmetry (압축-인장 비대칭을 고려한 AZ31 튜브의 압괴해석)

  • Yoon, Jong-Hun;Lee, Jung-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.9
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    • pp.997-1002
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    • 2012
  • With the increasing demand for lightweight materials to reduce fuel consumption, especially in the transportation industry, magnesium alloys are being widely studied. However, there are several limitations to the large-scale application of magnesium alloys in a structure because of their low formability and strong anisotropy. In order to take into account both the strong anisotropy and tension-compression asymmetry of AZ31 sheet alloy, the Cazacu-Plunkett-Barlat yield criterion (Cazacu, 2006) was adopted in material modeling. The variation of the anisotropic coefficients that describe the yield surface evolution of AZ31 is optimized using an interpolation function based on specific calibration results. It generates continuous yield surfaces, which makes it possible to describe different hardening rates in tension and compression as well as the tension-compression asymmetry of magnesium alloys. The performance of the CPB06 yield criterion for simulating an axial crushing test was tested and compared with that of the Hill (1948) yield criterion.

Test and Analysis for Axial and Bending Collapse Characteristics Evaluation of Aluminum Extruded Beams (알루미늄 압출재의 압괴 및 굽힘붕괴 특성규명을 위한 시험 및 해석)

  • 김범진;허승진;구정서;송달호
    • Journal of the Korean Society for Railway
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    • v.4 no.3
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    • pp.110-115
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    • 2001
  • Recently, many engineers actively participate in research and development w.r.t the weight reduction and the safety increase of vehicle body structure to meet the requirement of fuel economy and regulations. However, vehicle design concept related with weight reduction and safety increase is reduced to the design conflict problem. In the paper, the axial and bending collapse test of aluminum extruded beams are performed and the collapse characteristics are investigated. The analysis method to verify the fracture characteristics of aluminum extruded beam is presented and discussed.

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Scale Modeling Technique for the Crash Analysis of Railway Vehicle Structure (철도차량 충돌 해석을 위한 축소모델링 기법 연구)

  • 김범진;허승진
    • Journal of the Korean Society for Railway
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    • v.5 no.4
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    • pp.231-236
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    • 2002
  • Todays, crash safety requirements of the railway vehicle structures become important design criterion according to the increased driving speed and the lightweight construction. Although the crash analysis using computer simulation can be effectively applied to predict the crash performance of the railway vehicles in the early design stage, the optimized design w.r.t the crash safety could be realized by the crash tests with actual prototype vehicles. However, it is very expensive and time-consuming task to perform the crash test of the railway vehicles. As a measure to cope with the problem, in this paper, the scale modeling technique is suggested and experimentally verified to predict the impact energy absorption characteristics of full scale model of aluminum extrusions sub-structures and the high-speed railway vehicle structure.

A Study on the Mechanical Properties of Concrete Filled Steel Tube Column under Centric Axial Load (중심축력을 받는 콘크리트 충전강관 기둥의 역학적 거동 특성에 관한 연구)

  • 박정민;김화중
    • Magazine of the Korea Concrete Institute
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    • v.7 no.5
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    • pp.133-144
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    • 1995
  • This study investigated to the properties of structural behaviors through a series of experiment with the key parameter, such as diameter-to-thickness(D/t) ratio, selenderness ratio of steel t~ube and strength of concrete under loading condition simple confined concrete by steel tube as a fundmental study on adaptability with structural members in high-rise building. The obtained results are sumnarised as follow. (1) The fracture mode of confined concrete was presented digonal tension fracture in the direction of $45^{\circ}$ with compression failure at the end of specimen in stub column, but the fracture mode of long column was assumed an aspect of bending fracture transversely. (2) The deformation capacity and ductility effect was increased by confine steel tube for concrete. (3) 'The emprical formula to predict the ultimate capacity of confined concrete by steel tube and concrete filled steel tube column using restraint of concrete considered D / t ratio, selenderness ratio of steel tube anti strength of' concrete were proposed.

Study on a 2-Dimensional Dynamic Modeling Technique to Analyze the Overriding Phenomena of Rollingstock (열차의 타고오름 해석을 위한 2차원 충돌동역학 모델링 기법 연구)

  • Kim, Geo-Young;Koo, Jeong-Seo;Kwon, Tae-Soo
    • Journal of the Korean Society for Railway
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    • v.14 no.1
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    • pp.11-18
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    • 2011
  • This paper proposed a new 2-D multi-body dynamic modeling technique to analyze overriding behaviors taking place during train collision. This dynamic model is composed of nonlinear springs, dampers and masses by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model for rollingstock, energy absorbing capacities of collision elements, accelerations of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we chose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3-D finite element analysis, and established a 2-D multi-body dynamic model. This 2-D dynamic model was simulated under the train-to-train collision scenarios, and evaluated with 3-D virtual testing model. It was founded from the simulation results that this 2-D dynamic model could well predict overriding behaviors, and the modeling technique of carbody deformation was very important in overriding estimation.