• Journal of Mechanical Science and Technology
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• 제17권4호
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• pp.501-510
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• 2003

The spot welded sections of automobiles such as the hat and double hat section members, absorb the most of the energy during the front-end collision. The purpose of this study was to analyze the collapse characteristics of spot welded section members with respect ttl the pitch or spot welds on flanges. through impact experiments and computation for para-closed sections and perfectly closed sections. The hat shaped section members were tested at the impact collapse velocities of 4.72 m/sec, 6.54 m/sec and 7.19 m/sec and double hat shaped section members were tested at the impact collapse velocities of 6.54 m/sec, 7.19 m/sec and 7.27 m/sec. A commercial LS-DYNA3D was used to simulate the collapse behavior of the hat and double hat shaped section members. The validity of the simulation was to be proved by comparing the simulation results and the experimental results.

• 대한기계학회논문집A
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• 제25권7호
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• pp.1131-1138
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• 2001

This paper concerns the crashworthiness of the widely used vehicle structure, the spot welded hat and double hat shaped section members, which are excellent on the point of the energy absorbing capacity and low production cost. The target of this paper is to analyze the energy absorption capacity of the structure against the front-end collision, and to obtain useful information for designing stage. Changing the spot weld pitches on the flanges, the hat and double hat shaped section members were tested on the axial collapse loads in impact velocities of 4.72m/sec, 6.54m/sec, 7.19m/sec and 7.27m/sec. To efficiently review the collapse characteristics of these sections, the simulation have been carried out using explicit FEM package, LS-DYNA3D. The solutions are compared with results from the impact collapse experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.650-654
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• 1995

In this study, in order to measure energy-absorbing charactistics in collapse test of CFRP thin-walled laminates and interpretate the cause of decreasing age when collapse test is carried out under the environments of high temperatures and hygrothermals, the moisture absorbing behavior according to the variety of orientation angel is observed and collapse characteristics is compared with the influence of high temperatures and hygrothermals. Especially, we supposed to clearly understand reationship between collapse characteristics in proportion to the variety of orientation angel and moisture absorbing. The value of the maximum loading, mean loading,rate of energy absorption energy per unit volume and mass in CFRP thin-walled laminates on the high temperatures and hygrothermals is measured lower than under no moisture absorbing. The maximum collapse loading in dynamic impact test is taken measurement lower than in static collapse test regarding compared with collapse characteristics conformity with the variety of the CFRP circular laminates in high temperatures and hygrothermals. But the absorbed energy per unit mass and volume is almost same and the biggest amount of energy is shown in the CFRP circular laminates with orientation angel of 15 .deg.. Therefore, in the case of use to CFRP circular laminates with axisymmetric mode, CFRP thin-walled structal members with orientation angel of 10 .deg. , 15 . deg. are generally useful.

• 대한조선학회논문집
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• 제36권2호
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• pp.77-93
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• 1999

본 연구에서는 충격횡압력을 받는 선체 판부재의 붕괴강도 특성을 분석하고 충격하중 효과를 고려한 간이 구조설계식을 제시하고자 한다. 충격횡압력하에 판부재의 붕괴거동을 분석하기 위해 기존의 실험결과와 더불어 범용 비선형 유한요소해석 프로그램인 STARDYNE을 이용하였다. 이론적 방법으로는 먼저 강소성이론을 이용하여 정적 횡압력을 받는 판부재에 대한 붕괴강도식을 도출하였다. 또한, 변형률속도 효과를 고려하여 충격 횡압력 문제에도 적용하였다. 실제 판부재에 적용 예로써 충격횡압력을 받는 강판부재와 알루미늄합금 보강판부재에 대한 붕괴거동을 분석하였다.

• 한국정밀공학회지
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• 제17권5호
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• pp.195-201
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• 2000

The fundamental spot welded sections of automobiles (hat-shaped and double hat-shaped sections) absorb most of the energy in a front impact collision. The sections of various thickness, shape and weld width on the flange lave been tested on axial impact crush load (Mass 40kg, Velocity 7.19m/sec) using a vertical air pressure crash est device Characteristics of impact collapse have been reviewed and a structure of optimal energy absorbing capacity is suggested.

• Journal of Advanced Marine Engineering and Technology
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• 제27권1호
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• pp.76-81
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• 2003

The purpose of this study is to analyze the collapse characteristics of widely used spot welded section members coated damping material Y1000 and to develop an analysis method for acquiring exact collapse loads and energy absorption ratio. Hat-shaped thin-walled members have the biggest energy absorbing capacity in a front-end collision. The sections were tested on quasi-static and impact loads. Specimens with two type thickness, width ratio and spot weld pitch on the flange have been tested in impact velocities(6.73n0sec and 7.54n1sec) which imitate a real-life car collision. As a result, it was developed the system for acquiring impact energy absorbing characteristics of structure united thin-walled member and damping materials.

• 한국안전학회지
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• 제13권3호
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• pp.11-23
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• 1998

In this study, collapse test of thin-walled structure is performed under axially quasi-static and impact load in collapse characteristic to develop the optimum structural member for a light-oriented automobile. Furthermore, the energy-absorbing capacity is observed according to the variety of configuration(circular, square), aspect ratio in aluminum specimen to obtain basic data for the improved member of vehicle. In both quasi-static and impact collapse test, Al circular specimens collapse, in general, with axisymmetric mode in case of thin thickness while collapse with non-axisynmetric mode according to the thickness increase. For Al rectangular specimens, they collapse with axisymmetric mode in case of thin thickness, with mixed collapse mode according to the increase of thickness. In terms of initial max. load, Al square specimen turns out the best member among specimens, and then Al square, circular and circular with large scaling ratio, respectively. In case of quasi-static compression test, the absorbed energy per unit volume and mass shows higher in Al circular specimen, and then Al square, circular with large scaling ratio, respectively, according to shape ratio the absorbed energy per unit volume and mass in case of max. impact compression load is higher than that of static load. But the absorbed energy per unit volume and mass shows that Al circular specimen is the best member. Especially, unlike max. compression loan, the absorbed energy per unit volume and mass in impact test turns out the low value.

• 한국생산제조학회지
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• 제20권1호
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• pp.17-22
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• 2011

Ultimate goals in vehicle design can be summarized as environment-friendliness and safety. Along with these requirements, the importance of natural environment conservation has been focused lately. Therefore, reduced emission from vehicle and improved efficiency has become the top priority projects throughout the world. CFRP(Carbon Fiber Reinforced Plastics) of the advanced composite materials as structure materials for vehicles, has a widely application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness. This study is to investigate the energy absorption characteristics of CFRP hat-shaped section members under the axial impact collapse test. The CFRP hat-shaped section members which manufactured from unidirectional prepreg sheets were made of 8plies. The axial impact collapse tests were carried out for each section members. The collapse mode and energy absorption characteristics were analyzed for CFRP hat-shaped section member according to the interface numbers(2, 3, 4, 6 and 7).

• 한국안전학회지
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• 제29권5호
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• pp.7-14
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• 2014

This study aimed to develop members with the optimum impact characteristics to ensure a protected space for passengers in the case of automobile collisions. Accordingly, these members were fabricated to provide sufficient rigidity and safety to the passenger room structure and to absorb large amounts of energy during collision. In particular, CFRP members were fabricated with different section shapes such as square and single- and double-hat shapes. Next, their impact collapse characteristics and collapse modes were quantitatively analyzed according to the changes in section shapes and stacking angles. This analysis was performed to obtain design data that can be applied in the development of optimum lightweight members for automobiles.

• 한국정밀공학회지
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• 제17권12호
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• pp.129-136
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• 2000

In the frontal collision the spot welded hat-shaped section side member is the fundamental structure for automobiles and has a great amount of absorbing capacity. For this reason LS-DYNA3D has been used for analyzing impact collapse characteristics on hat shaped section member with respect to the valuables; thickness, width ratio and spot weld potch on impact load(7.19m/sec, 1034J). By comparing the results from simulation and the experimental results, the utilization of simulation has been certified.