• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.32-38
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• 2002

The purpose of this study is to analyze the collapse characteristics of widely used spot welded section members (hat and double hat section, nembers of vehicles) which possess the greatest energy absorbing capacity In an axial impact collapse. This study also suggests how the collapse load and deformation mode are obtained under impact. In the program system presented in this study, an explicit finite element code, LS-DY7A3D, is adopted for simulating complicated collapse behavior of the hat and double hat shaped section members with respect to section dimensions and spot weld pitches. Comparing the results with experiments, the simulation has been verified under a velocity of 7.19 m/sec (impact energy of 1034J)

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.241-247
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• 2009

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of a structure members in automobiles. We have studied to investigate collapse characteristics and moisture absorption movements of CFRP(Carbon Fiber Reinforced Plastics) hat shaped sectional members when CFRP laminates are under the hygrothermal environment. In particular, the absorbed energy, mean collapse load and deformation mode were analyzed for side members which absorbed most of the collision energy. Variation of CFRP interlaminar numbers is important to increase the energy absorption capability. Therefore we have made a static collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.507-513
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• 2009

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of structure members in automobiles. We have investigated collapse characteristics and moisture absorption movements of CFRP(Carbon Fiber Reinforced Plastics) hat shaped sectional members when CFRP laminates are under the hygrothermal environment. The absorbed energy, mean collapse load and deformation mode were analyzed for side members which absorbed most of the collision energy. Therefore we have made a static collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed specimen.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.7
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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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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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).

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.192-199
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• 2000

The spot-welded automotive side member which has a hat-shaped section and a double hat shaped section has been tested on the axial static(10mm/min) and quasi-static(50mm/min) compressing load. The collapse characteristics of automotive sections have been reviews on shift on shape and in width of the spot-voiding on the flange. On the basis of the results of tests and reviews, the optimum energy absorption capacity of the structure has been studied.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.6 s.261
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• pp.671-678
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• 2007

Front-side members of automobile, such as the hat shaped section members, are structures with the greatest energy absorbing capability in a front-end collision of vehicle. This paper was performed to analyze energy absorption characteristics of the hat shaped section members, which are basic shape of side member. The hat shaped section members consisted of the spot welded side member which was utilized to an actual vehicle and CFRP side member for lightweight of vehicle structural member. The members were tested under static axial loading by universal testing machine. Currently, stacking condition related to the collapse characteristics of composite materials is being considered as an issue fer the structural efficiency and safety of automobiles, aerospace vehicles, trains, ships even elevators during collision. So, energy absorption characteristics were analyzed according to stacking condition and shape of section and compared the results of spot welded side member with those of CFRP side member.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1549-1552
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• 2003

The front-end side members of automobiles absorb most of the energy in a front-end collision. The front-end side members are required to have a high stiffness together with easiness to collapse sequentially to absorb more impact energy. The axial static collapse test (5mm/mim) was conducted by using UTM with respect to the single hat shaped section members which are the standard section shape of the spot welded section members, to the single cap shaped section members, to the double cap shaped section members and to the double hat shaped section members whose section shape are changed in order to give more stiffness. As a result of test, the energy absorbing characteristic was analyzed for different section shapes. That is, it was analyzed that the change of section shape influenced the absorbing energy, the mean collapse load and the maximum collapse load, and that the relation between the change of section shape and the collapse mode.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.782-789
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• 2010

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of a structure member in automobiles. In this paper, we have studied to investigate collapse characteristics and moisture absorption movements of CFRP( carbon fiber reinforced plastics) structure members when CFRP laminates are under the hygrothermal environment. In particular, the absorbed energy, mean collapse load and deformation mode were analyzed for CFRP members which absorbed most of the collision energy. Also, variation of stacking angle is important to increase the energy absorption capability. The purpose of this study is to evaluate the strength reduction and moisture absorption behavior of CFRP hat shaped member. Therefore we have made a impact collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed. As a result, the effect of moisture absorption and impact loads of approximately 50% reduction in strength are shown.