• 한국자동차공학회논문집
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• 제21권4호
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• pp.128-134
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• 2013

High bending collapse performance (maximum resistance force and mean resistance force) of body center pillar is an important design target for vehicle safety against side impact. In this study, effect of the upper section shape and the thickness of outer reinforcement on bending collapse performance was investigated for the center pillar of a large passenger car. First, through bending collapse analyses using simple models with uniform section, an optimized center pillar upper section was chosen. Next, bending collapse performance for various models of the actual center pillar with changing the thickness of outer reinforcement were analyzed. The finally designed model showed distinctive enhancement in bending collapse performance nearly without weight increase.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.41-49
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• 2007

More diversified and strengthened safety regulations require higher safety vehicle with less weight. The structural foam can play a role for restraining section distortion of main body members undergoing bending collapse at vehicle crash. In this study, using structural foam modeling technology, validated in previous work, the bending collapse characteristics were evaluated for two types of circular and actual vehicle body frame sections. With changing the foam filling method, outer panel thickness and section shape, load carrying capability and absorbed energy were observed. The results indicate valuable design strategy for effectively elevating bending collapse performance of body members with foam filled.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.76-79
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• 2005

Bending deformation and energy absorption characteristics of aluminum-composite hybrid tube beams have been analyzed for improvement in the bending performance of aluminum space frame by using experimental tests combined with theoretical and finite element analyses. Hybrid tube beams composed of glass fabric/epoxy layer wrapped around on aluminum tube were made in autoclave with the recommended curing cycle. Basic properties of aluminum material used for initial input data of the finite element simulation and theoretical analysis were obtained from the true stress-true strain curve of specimen which had bean extracted from the Al tube beam. A modified theoretical model was developed to predict the resistance to the collapse of hybrid tube beams subjected to a bending load. Theoretical moment-rotation angle curves of hybrid tube beams were in good agreement with experimental ones, which was comparable to the results obtained from finite element simulation. Hybrid tube beams strengthened by composite layer on the whole web and flange showed an excellent bending strength and energy absorption capability.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.133.1-133.1
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• 2005

• Earthquakes and Structures
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• 제13권2호
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• pp.211-220
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• 2017

Observations from past strong earthquakes revealed that near-fault ground motions could lead to the failure, or even collapse of electricity transmission towers which are vital components of an overhead electric power delivery system. For assessing the performance and robustness, a high-fidelity three-dimension finite element model of a long span transmission tower-line system is established with the consideration of geometric nonlinearity and material nonlinearity. In the numerical model, the Tian-Ma-Qu material model is utilized to capture the nonlinear behaviours of structural members, and the cumulative damage D is defined as an index to identify the failure of members. Consequently, incremental dynamic analyses (IDAs) are conducted to study the collapse fragility, damage positions, collapse margin ratio (CMR) and dynamic robustness of the transmission towers by using twenty near-fault ground motions selected from PEER. Based on the bending and shear deformation of structures, the collapse mechanism of electricity transmission towers subjected to Chi-Chi earthquake is investigated. This research can serve as a reference for the performance of large span transmission tower line system subjected to near-fault ground motions.

• 한국해양공학회지
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• 제2권2호
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• pp.71-77
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• 1988

For the collapse of structures due to the variable repeated load, two types of collapse mechanisms, i.e., incremental collapse and alternating plasticity, exist. Under the similar variable repeated loading conditions there exists shakedown state in the structures. In shakedown state, the number of plastic hinges are not increased and all further loading will be resulted in the elastic moment changes. Namely, under the shakedown state, structures do not collapse. In this investigation, shakedown analysis are performed by composing new computer programs. Basic theories employed to compose the programs are as follows. 1. Newton-Raphson methods are added to the existing matrix method for the plastic analysis. 2. An effort to construct the stiffness of axial and bending springs attached at both ends of the member has been made. By using the programs developed, it is possible to anticipate the collapse mechanisms (Incremental collapse, alternating plasticity). Lastly for the verification of performance of the program, demonstration examples have been solved and the results are compared with other sources.

• Steel and Composite Structures
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• 제50권3호
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• pp.265-280
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• 2024

The collapse behavior observed in single-story beam-column assembly (SSBCA) do not accurately represent the actual overall stress characteristic of multi-story frame structure (MSFS) under column loss scenario owing to ignoring the interaction action among different stories, leading to a disconnection between the anti-collapse behaviors of "components" and "overall structures", that is, the anti-collapse performance of frame structures with two different structural scales has not yet formed a combined force. This paper conducts a numerical and theoretical study to explore the difference of the collapse behaviors of the SSBCA and MSFS, and further to reveal the internal force relationships and boundary constraints at beam ends of models SSBCA and MSFS. Based on the previous experimental tests, the corresponding refined numerical simulation models were established and verified, and comparative analysis on the resistant-collapse performance was carried out, based on the validated modeling methods with considering the actual boundary constraints, and the results illustrates that the collapse behaviors of the SSBCA and MSFS is not a simple multiple relationship. Through numerical simulation and theoretical analysis, the development laws of internal force in each story beam under different boundary constraints was clarified, and the coupling relationship between the bending moment at the most unfavorable section and axial force in the composite beam of different stories of multi story frames with weld cover-plated flange connections was obtained. In addition, considering the effect of the yield performance of adjacent columns on the anti-collapse bearing capacities of the SSBCA and MSFS during the large deformation stages, the calculation formula for the equivalent axial stiffness at the beam ends of each story were provided.

• Composites Research
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• 제20권3호
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• pp.8-16
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• 2007

자동차 충돌이나 전복사고에 있어서 부재들의 변형은 축방향 압축붕괴와 함께 굽힘붕괴가 혼합된 변형양상을 보여주고 있으며, 자동차에 사용되는 대부분의 박벽관 부재는 굽힘붕괴가 주된 붕괴형태로 나타나고 있다. 하지만 혼성 사각관의 굽힘붕괴에 대한 연구는 축방향 붕괴의 연구에 비해 많이 부족한 현실이다. 본 논문에서는 알루미늄-복합재료 혼성 사각관의 굽힘 붕괴 거동 및 에너지 흡수 특성을 실험적 방법으로 연구하여 경량화 구조부재로서의 적용가능성을 조사하였다. 접착필름 살입형 경화법으로 제작된 알루미늄-복합재료 혼성 사각관 보에 대해 복합 재료 층의 적층두께와 적층 각에 따른 굽힘 성능을 평가하였다. 본 혼성 사각관 보는 복합재료만으로 구성된 사각관 보에서 발생할 수 있는 불안정한 붕괴모드를 안정적인 붕괴로 전환시키면서, 단순 알루미늄 사각관에 비해 에너지 흡수 능력이 향상되었고, 특히 $[0^{\circ}/90^{\circ}]s$를 적층한 혼성 사각관의 경우 벽두께 1mm인 알루미늄 사각관 시험편과 비교하여 흡수에너지가 1.78배 증가하였고 단위무게당 흡수에너지는 1.29배로 증가함을 보였다.

• 한국자동차공학회논문집
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• 제22권2호
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• pp.52-59
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• 2014

Front impacted SUV vehicle shows that the front parts of side members are collapsed by the bending due to the transverse load exerted at the end of side members. Side member models were impacted with various angles in order to study the crash performance according to the impact angle. Even for the small impact angle of $10^{\circ}$, crash performance seriously deteriorated and the deformations for impact angle $15^{\circ}$ were similar to those from the front body impact analysis. In addition, the angled front impact analysis for the straight member with hat section was carried out and the effects of inner reinforcement shape on crash performance was investigated.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.171-180
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• 2005

Bending performances of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been evaluated using experimental tests combined with theoretical and finite element analyses. A finite element simulation for the three-point bending test was performed. Basic properties of aluminum materials used for initial input data of the finite element simulation were obtained from the true stress-true strain curves of specimens which had been extracted from the Al tube beams. True stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing, and true strains were obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens adhered by aluminum plates were employed fur the bending test. The bending deformation behaviors up to the maximum load described by the numerical simulation were in good agreement with experimental ones. After passing the maximum load, reinforcing plate was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed an excellent bending capability.