• Title/Summary/Keyword: Impact Collapse Characteristics

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A Study on Characteristics of Damageability and Repairability with Similar Platform Type at Low Speed 40% Offset Crash Test (동일 플렛폼 차량에 대한 저속 충돌시 손상성 수리성에 미치는 영향에 관한 연구)

  • Lim, Jong-Hun;Park, In-Song;Heo, Seung-Jin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.2
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    • pp.108-113
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    • 2005
  • The damageability and repairability of similar platform type vehicles could be very concerned with design optimization. In all the vehicles crash tested, small size passenger vehicles were weakness in aspect of damageability and repairability. The most critical area appears to be repair cost considering that parts cost is the largest portion of total repair cost segments. Besides repair cost, attaching method of front sidemember and subframe are placed special importance for impact energy absorption and damageability and repairability. So in order to improve damageability and repairability of vehicle structure and body component of the monocoque type passenger vehicles, the end of front side member and front back beam should be designed with optimum level and to supply the end of front side member as a partial condition approx 300mm. The effectiveness of design concept on the 40% offset frontal impact characteristics of the passenger vehicle structure is investigated and summarized.

Design Vessel Selection of Maritime Bridges using Collision Risk Allocation Model (충돌위험분배모델을 이용한 해상교량의 설계선박 선정)

  • Lee, Seong-Lo;Lee, Byung Hwa;Bae, Yong-Gwi;Shin, Ho-Sang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.3
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    • pp.123-134
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    • 2006
  • In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of the maritime bridge. Method II which is a probability based analysis procedure is used to select the design vessel for collision impact from the risk analysis results. The analysis procedure, an iterative process in which a computed annual frequency of collapse(AF) is compared to the acceptance criterion, includes allocation method of acceptance criterion of annual frequency of bridge component collapse. The AF allocation by weights seems to be more reasonable than the pylon concentration allocation method because this AF allocation takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. From the assessment of ship collision risk for each bridge pier exposed to ship collision, a representative design vessel for all bridge components is selected. The design vessel size varies much from each other in the same bridge structure depending upon the vessel traffic characteristics.

Ship Collision Risk Assessment for Bridges (교량의 선박충돌위험도 평가)

  • Lee, Seong Lo;Bae, Yong Gwi
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1A
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    • pp.1-9
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    • 2006
  • An analysis of the annual frequency of collapse(AF) is performed for each bridge pier exposed to ship collision. From this analysis, the impact lateral resistance can be determined for each pier. The bridge pier impact resistance is selected using a probability-based analysis procedure in which the predicted annual frequency of bridge collapse, AF, from the ship collision risk assessment is compared to an acceptance criterion. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed AF is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The distribution of the AF acceptance criterion among the exposed piers is generally based on the designer's judgment. In this study, the acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. To determine the design impact lateral resistance of bridge components such pylon and pier, the numerical analysis is performed iteratively with the analysis variable of impact resistance ratio of pylon to pier. The design impact lateral resistance can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. More researches on the allocation model of AF and the determination of impact resistance are required.

The Absorbed Energy Characteristics of Gr/E Composite Tubes under Axial Collapse Load (축 압궤하중을 받는 Gr/E 복합재 튜브의 에너지 흡수특성)

  • 양현수;김영남;최흥환
    • Journal of the Korea Safety Management & Science
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    • v.4 no.2
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    • pp.189-197
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    • 2002
  • Composites have wide applications in aerospace vehicles and automobiles because of the inherent flexibility in their design lot improved material properties. Composite tubes in particular, are potential candidates for their use as energy absorbing elements in crashworthiness applications due to their high specific energy absorbing capacity and the stroke efficiency. Their failure mechanism however is highly complicated and rather difficult to analyze. This includes fracture in fibers, in the matrix and in the fiber-matrix interface in tension, compression and shear. The purpose of this study is to investigate the energy absorption characteristics of Gr/E(Graphite/Epoxy) tubes on static and impact tests. The collapse characteristics and energy absorption of a variety of tubes have been examined. Changes in the lay-up which increased the modulus increased the energy absorption of the tubes. Based on the test results, the following remarks can be made: Among CA15, CA00 and CA90 curves the CA90 tube exhibits the highest crush load throughout the whole crush process, and max load increases as interlaminar number increase. Among all the tubes type CC90 has the largest specific crushing stress of 52.60 kJ/kg which is much larger than other tubes.

Impact Characteristics of CFRP Structural Member according to the Variation of Stacking Condition and Impact Energy (적층구성과 충돌에너지의 변화에 따른 CFRP 구조부재의 충격특성)

  • Yeo, In-Goo;Choi, Ju-Ho;Choi, Yeong-Min;Yang, Yong-Jun;Hwang, Woo-Chae;Yang, In-Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.6
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    • pp.976-981
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    • 2013
  • This aims to examine experimentally the absorption behavior and strength of circular CFRP members with different stacking configurations on exposure to a separate impact velocity. In addition, considered the dynamic characteristics. Circular and square CFRP members were prepared from 8-ply unidirectional prepreg sheets stacked at different angles ($0^{\circ}/90^{\circ}$ and $90^{\circ}/0^{\circ}$, where the $0^{\circ}$ direction coincides with the axis of the member) and interface numbers (2, 4, and 6). Based on the collapse characteristics of the circular CFRP members. In this study, for the circular members, the impact energies at crosshead speeds of 5.52 m/s, 5.14 m/s, and 4.57 m/s are 611.52 J, 529.2 J, and 419.44 J (at circular members), respectively. Likewise, for the square members, the impact energies at crosshead speeds of 2.16 m/s, 1.85 m/s, and 1.67 m/s are 372.4 J, 274.4 J, and 223.44 J (at square members).

Ship Collision Risk of Suspension Bridge and Design Vessel Load (현수교의 선박충돌 위험 및 설계박하중)

  • Lee, Seong Lo;Bae, Yong Gwi
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1A
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    • pp.11-19
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    • 2006
  • In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of suspension bridge. Method II in AASHTO LRFD bridge design specifications which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. From the assessment of ship collision risk for each bridge pier exposed to ship collision, the design impact lateral strength of bridge pier is determined. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed annual frequency of collapse(AF) is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. This AF allocation method is compared to the pylon concentration allocation method to obtain safety and economy in results. This method seems to be more reasonable than the pylon concentration allocation method because AF allocation by weights takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. The design vessel for each pier corresponding with the design impact lateral strength obtained from the ship collision risk assessment is then selected. The design impact lateral strength can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. Therefore more researches on the allocation model of AF and the selection of design vessel are required.

Design of the Impact Energy Absorbing Members and Evaluation of the Crashworthiness for Aluminum Intensive Vehicle (알루미늄 초경량 차체의 충격 흡수부재 설계 및 충돌 안전도 평가)

  • Kim, Heon-Young;Kim, Jin-Kook;Heo, Seung-Jin;Kang, Hyuk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.1
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    • pp.216-233
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    • 2002
  • Due to the environmental problems of fuel consumption and vehicle emission, etc., automotive makers are trying to reduce the weight of vehicles. The most effective way to reduce a vehicle weight is to use lighter materials, such as aluminum and plastics. Aluminum Intensive Vehicle(AIV) has many advantages in the aspects of weight reduction, body stiffness and model change. So, most of automotive manufacturers are attempting to develop AIV using Aluminum Space Frame(ASF). The weight of AIV can be generally reduced to about 30% than that of conventional steel vehicle without the loss of impact energy absorbing capability. And the body stiffness of AIV is higher than that of conventional steel monocoque body. In this study, Aluminum Intensive Vehicle is developed and analyzed on the basis of steel monocoque body. The energy absorbing characteristics of aluminum extrusion components are investigated from the test and simulation results. The crush and crash characteristics of AIV based on the FMVSS 208 regulations are evaluated in comparison with steel monocoque. Using these results, the design concepts of the effective energy absorbing members and the design guide line to improve crashworthiness for AIV are suggested.

Axial Collapse Characteristics of Aluminum/Carbon Fiber Reinforced Plastic Composite Thin-Walled Members with Different Section Shapes (단면형상이 다른 Al/CFRP 혼성박육부재의 축압궤특성)

  • Hwang, Woo Chae;Lee, Kil Sung;Cha, Cheon Seok;Kim, Ji Hoon;Ra, Seung Woo;Yang, In Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.9
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    • pp.959-965
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    • 2014
  • In the present study, we aimed to obtain design data that can be used for the side members of lightweight cars by experimentally examining the types of effects that the changes in the section shape and outermost layer of an aluminum (Al)/carbon fiber reinforced plastic (CFRP) composite structural member have on its collapse characteristics. We have drawn the following conclusions based on the test results: The circular Al/CFRP composite impact-absorbing member in which the outermost layer angle was laminated at $0^{\circ}$ was observed to be 52.9 and 49.93 higher than that of the square and hat-shaped members, respectively. In addition, the energy absorption characteristic of the circular Al/CFRP composite impact-absorbing member in which the outermost layer angle was laminated at $90^{\circ}$ was observed to be 50.49 and 49.2 higher than that of the square and hat-shaped members, respectively.

Collapse Characteristics of CFRP Hat Member with Outer Laminated Angle Changes under Hygrothermal Environment with Temperature Changes (다양한 열습환경하에서 최외각층 변화에 따른 CFRP 모자형 부재의 압궤특성)

  • Yang, Yongjun;Hwang, Woochae;Yang, Inyoung
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.3
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    • pp.243-249
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    • 2014
  • Currently, CFRP composites are rapidly replacing steel plates, as they are lighter, stronger, and more elastic; however, they are poorly suited to hygrothermal and impact-collapsed environments because moisture can alter their molecule arrangement and chemical properties. In this study, environments are experimentally simulated in order to investigate changes in the moisture absorption inside a CFRP composite and to determine its weakest point. Moreover, changes in the moisture absorption ratio at temperatures of $60^{\circ}C$ and $80^{\circ}C$ are studied and compared in order to understand how changes in temperature affect moisture absorption inside CFRP composites. Results show that moisture absorption leads to a strength reduction of around 50%. In addition, the moisture absorption rate inside CFRP composites is shown to change rapidly with increasing temperature. Accordingly, it showed that the change in matrix also has a weak point.

Rollover Analysis of a Bus using Beam Element and Nonlinear Spring Characteristics (보 요소와 비선형 스프링 특성을 이용한 버스 전복 해석)

  • Park, Su-Jin;Yoo, Wan-Suk;Kwon, Yuen-Ju;Kim, Jin-Bae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.1
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    • pp.56-63
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    • 2007
  • In case of bus rollover, the body structure of the bus should be designed to ensure the survival space for passengers. So, this study focuses on evaluating rollover strength through a computer simulation using the commercial code, LS-DYNA3D at the initial stage of vehicle development. For this study, section structure was modeled using a simple beam element, and impact boundary conditions required by ECE(Economic Commission for Europe) regulation No.66 were applied. In order to confirm the validity of the beam element bus model, the results compared with the test results and shell element bus model. The analysis errors from beam element bus model are due to the difference in strain energy of joint area between beam and shell model. In this study, a method for the joint modeling was suggested by using nonlinear springs to which the collapse mechanisms were applied.