• Title, Summary, Keyword: Crush Test

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Effects of Defect Size on Crush Test Load of Butt Fusion Welded MDPE Pipes

  • Tun, Nwe Ni;Lai, Huan Sheng;Jeon, Gyu Min;Yoon, Kee Bong;Kil, Seong Hee
    • Journal of Energy Engineering
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    • v.24 no.4
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    • pp.55-62
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    • 2015
  • It is expected that the size of welding defect affects the mechanical performance of welded medium density polyethylene (MDPE) pipe joints. In this study, butt fusion welded MDPE pipe joints with a single spherical or planar defect of various sizes were studied using experimental crush testing and also by finite element method. The crush test showed that the mechanical performance of crush was not affected by the size and geometry of a single welding defect when the defect size was increased to 45% of the pipe's wall thickness. The simulation results indicated that the effect of the single welding defect on the Von Mises stress distribution near the defect explained the reason of the test results.

Study of Crush Strength of Aluminum Honeycomb for Shock Absorber of Lunar Lander (달착륙선 충격흡수장치용 알루미늄 허니콤의 Crush Strength에 관한 연구)

  • Kim, Shin;Lee, Hyuk-Hee;Kim, Hyun-Duk;Park, Jung-Sun;Im, Jae-Hyuk;Hwang, Do-Soon
    • Journal of Aerospace System Engineering
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    • v.4 no.3
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    • pp.1-5
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    • 2010
  • Understanding the crushing behaviour of aluminum honeycombs under dynamic loading is useful for crash simulations of vehicles and for design of impacting energy absorbers. In the study of honeycomb crushing under quasi-static, dynamic loading, the most important parameter is crush strength. Crush strength is indicated to energy absorption characteristic of aluminum honeycomb. In this study, Using Finite Element Analysis carried out crush strength of hexagonal aluminum honeycomb then the results was compared with Quasi-static test. Consequently, Crush strength is different in quasi-static loading and dynamic loading about 16%.

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Roof Crush Analysis Technique Using Simple Model with Plastic Hinge Concepts (소성 힌지를 갖는 단순 보 모델을 이용한 루프 붕괴 해석 기술)

  • 강성종
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.6
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    • pp.216-222
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    • 1996
  • This paper presents a computational technique to predict roof crush resistance in early design stage of passenger car development. This technique use a simple F.E. model with nonlinear spring elements which represent plastic hinge behavior at weak areas. By assuming actual sections as equivalent simple sections, maximum bending moments which weak areas in major members can stand are theoretically calculated. Results from prediction of roof crush resistance are correlated well with test results.

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Dynamic Crush Strength Analysis of a Spacer Grid Assembly for a LWR Nuclear Fuel Assembly(II) (경수로 핵연료 지지격자의 동적 좌굴강도 해석(II))

  • Song, Kee-Nam;Lee, S.B.
    • Proceedings of the KSME Conference
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    • pp.590-592
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    • 2008
  • A spacer grid is one of the most important structural components in a LWR nuclear fuel assembly. The primary considerations are to provide a Zircaloy spacer grid with crush strength sufficient to resist design basis loads, without significantly increasing pressure drop across the reactor core. In this study, the dynamic crush strength analysis and test are carried out for the specimens of a spacer grid assembly.

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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.

Effects of Low Power Laser on Pain Response and Axonal Regeneration in Rat Models with Sciatic Nerve Crush Injury

  • Lee, Hong-Gyun;Kim, Yong-Eok;Min, Kyung-Ok;Yoo, Young-Dae;Kim, Kyung-Yoon;Kim, Gye-Yeop
    • Journal of International Academy of Physical Therapy Research
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    • v.3 no.1
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    • pp.345-355
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    • 2012
  • This study purposed to examine the effect of low power laser on pain response and axonal regeneration. In order to prepare peripheral nerve injury models, we crushed the sciatic nerve of Sprague-Dawley rats and treated them with low power laser for 21 days. The rats were divided into 4 groups: normal group(n=10); control group(n=10) without any treatment after the induction of sciatic nerve crush injury; experimental group I(n=10) treated with low power laser(0.21$mJ/mm^2$) after the induction of sciatic nerve crush injury; and experimental group II(n=10) treated with low power laser(5.25$mJ/mm^2$) after the induction of sciatic nerve crush injury. We measured spontaneous pain behavior(paw withdrawal latency test) and mechanical allodynia(von Frey filament test) for evaluating pain behavioral response, and measured the sciatic function index for evaluating the functional recovery of peripheral nerve before the induction of sciatic nerve crush injury and on day 1, 7, 14 and 21 after the induction. After the experiment was completed, changes in the H & E stain and toluidine blue stain were examined histopathologically, and changes in MAG(myelin associated glycoprotein) and c-fos were examined immunohistologically. According to the results of this study, when low power laser was applied to rat models with sciatic nerve crush injury for 21 days and the results were examined through pain behavior evaluation and neurobehavioral, histopathological and immunohistological analyses, low power laser was found to affect pain response and axonal regeneration in both experimental group I and experimental group II. Moreover, the effect on pain response and axonal regeneration was more positive in experimental group I to which output 0.21$mJ/mm^2$ was applied than in experimental group II to which 5.25$mJ/mm^2$ was applied.

A Study on the Characteristics of Domestic Vehicle on the Roof Crush Test Considering the Enhanced Safety Standard, FMVSS 216 (북미 법규 강화를 고려한 국내 자동차의 천정강도 시험특성에 관한 연구)

  • Kim, Eun-Hee;Lee, Jae-Kwang;Lee, Moon-Gu;Hong, Min-Sung
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.18 no.4
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    • pp.348-354
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    • 2009
  • In order to reduce the risk of roll over crash, one of the greatest risk events, National Highway Traffic Safety Administration(NHTSA) issued Notice of Proposed Rulemaking(NPRM) enhancing the safety standard on roof crush resistance, FMVSS No. 216 and changing some part of the test procedure. According to this NPRM, the boundary Gross Vehicle Weight Rating(GVWR) of the vehicles applied by this standard is extended from 2,722kg(6000 lb) to 4,536 kg(10000 lb) and the applied test force is increased from 1.5 times to 2.5 times of Unloaded Vehicle Weight (UVW). Also the current limit on the amount of roof crush, 127mm(5 inch), is replaced with a new requirement of maintaining enough headroom without touching the head of a seated 50% male dummy. In this paper, we carried out the rollover crash test on some domestic cars and investigated their safety due to the KMVSS No. 92 and the enhanced safety standard, FMVSS No. 216, respectively. The result shows that most of them can satisfy the new standards but further tests will be necessary, especially for heavier cars.

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Experimental Study on Side Impact Characteristics for Automotives Door Module (자동차용 도어 모듈의 측면 충돌특성에 관한 실험적 연구)

  • Jeon, S.J.;Kim, M.H.;Lee, G.B.;Lee, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.318-318
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    • 2009
  • The door stiffness is one of the important factors side impact. Generally, the researches have been conducted on the assembled door module. This study is to analysis the side impact characteristics for automotives door module. The impact characteristics have been determined by door module side impact test machine. To determine the initial, intermediate and peak crush resistances use the plot of load versus displacement and obtain the integral of the applied load with respect to the crush distances specified below for each door tested. The initial crush resistance is the average force required to deform the door through the initial 6 inches of crush. The intermediate crush resistance is the average force required to deform the door through the initial 12 inches of crush. The peak crush resistance will be directly obtained from the plot of load versus displacement since it is the largest force required to deform the door through the entire 18 inches crush distance. The data are used to determine if a specific vehicle or item of automotives equipment meets the minimum performance requirements of the subject Federal Motor Vehicle Safety Standard(FMVSS). FMVSS Static 214, Side impact protection, specifies performance requirements for protection of occupants in side impact crashes.

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Evaluation Methods for Flat Crush Resistance of Corrugated Fiberboard with Microflutes

  • Youn, Hye-Jung;Kwon, Hyun-Seung;Lee, Hak-Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.41 no.5
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    • pp.8-14
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    • 2009
  • Corrugated fiberboard is a widely used packaging material because of its high compressive strength and stiffness despite light weight. Corrugated fiberboards with microflutes with height $\leq$ 1.5 mm, such as E, F or G, have been developed. As microflutes have a different geometry from other conventional flutes, they may behave differently in testing and require a new testing method. Therefore, we evaluated the flat crush resistance of corrugated fiberboard with microflutes according to the ISO and TAPPI standard test methods. In addition, the effects of specimen area and platen compression rate were examined. The goal of this study was to identify an appropriate method for flat crush test (FCT) of corrugated fiberboard with microflutes. When a test piece with a standard area was subjected to the FCT in accordance with ISO and TAPPI methods, microflute corrugated fiberboard demonstrated a different load-displacement curve. An area of 20 $cm^2$ was determined to be the most appropriate for FCTof microflute corrugated fiberboard.

A Study on the Axial Crush Analysis of a Rectangular Tube with Experimental Comparison (사각관의 붕괴해석 및 실험에 관한 연구)

  • 강신유;한동철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.10
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    • pp.2555-2562
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    • 1993
  • In this paper, the axial crush of the rectangular STS304 tube is analyzed using DYNA3D, and 10 models are tested under quasi-static load. The deformed shapes of analysis and test are present, and the analysis results are compared with the results of quasi-static test. This paper describes that free rotational boundary condition causes a very similar deformed shapes to expermental results, and using the elastic buclking modes as initial imperfecion shapes, the deformed shapes are very close to the experimental shapes.