• 한국안전학회지
• /
• 제27권6호
• /
• pp.20-25
• /
• 2012

Currently, the most important purpose in designing automobile is environment-friendly and safety performance aspect. CFRP(Carbon Fiber Reinforced Plastics) of the advanced composite materials as structure materials for vehicles, has a wide application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness. In this study, experimental investigations are carried out for CFRP single and double hat shaped section member in order to study the effect of various stacking condition. They were cured by heating to the appropriate curing temperature($130^{\circ}C$) by means of a heater at the vacuum bag of the autoclave. The stacking conditions were selected to investigate the effect of the interface numbers. The CFRP single and double hat shaped section members which manufactured from unidirectional prepreg sheets were made of 8ply. The static collapse tests performed and the collapse mode and energy absorption capability were analyzed according to interface number.

• Journal of Mechanical Science and Technology
• /
• 제15권2호
• /
• pp.180-191
• /
• 2001

The widely used spot welded sections of automobiles(hat and double hat shaped section members) absorb most of the energy in a front-end collision. The sections were tested with respect to axial static(10mm/min) and quasi-static(1000mm/min) loads. Based on these test results, specimens with various thicknesses, width ratios and spot weld pitches on the flange were tested at high impact velocity(7.19m/sec and 7.94m/sec) which simulates an actual car crash. Characteristics of collapse have been reviewed and structures for optimal energy absorbing capacity is suggested.

• Journal of Mechanical Science and Technology
• /
• 제17권4호
• /
• pp.501-510
• /
• 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
• /
• 제25권7호
• /
• pp.1131-1138
• /
• 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.

• 한국안전학회지
• /
• 제15권4호
• /
• pp.20-27
• /
• 2000

The hat shaped section members, spot welded strength resisting structures are the most energy absorbing ones of automobile components during the front-end collision. Under the static axial collapse load in velocity of 10mm/min and quasi-static collapse load in velocity of 1000mm/min, the collapse characteristics of the hat shaped section and double hat shaped section member have been analyzed by axial collapse tests with respect to the variations of spot weld pitches on the flanges. In addition, the quasi-static collapse simulations have been implemented in the same condition to the experiment's using FEM package, LS-DYNA3D. The simulated results have been verified in comparison with these from the quasi-static axial collapse tests. With the computational approaches the optimal energy absorbing structures can be suggested. Simulations are so helpful that the optimized data be supplied in designing vehicles in advance.

• 대한기계학회논문집A
• /
• 제25권1호
• /
• pp.98-105
• /
• 2001

The fundamental and widely used spot welded sections of automobiles (hat and double hat-shaped section members) absorb most of the energy in a front-end collision. The sections were tested on axial static(10mm/min) and quasi-static(1000mm/min) loads. Based on these test results, specimens with various thickness, shape and spot weld pitch on the flange have been tested with impact velocity(7.19m/sec) the same as a real life car clash. Characteristics of collapse have been reviewed and a structure of optimal energy absorbing capacity is suggested.

• International Journal of Automotive Technology
• /
• 제7권5호
• /
• pp.565-570
• /
• 2006

The development of a light-weight vehicle is in great demand for enhancement of fule efficiency and dynamic performance. The vehicle weight can be reduced effectively by using lightweight materials such as aluminum and magnesium. However, if such materials are used in vehicles, there are often instances when different materials such as aluminum and steel need to be joined to each other. The conventional joining method, namely resistance spot welding, cannot be used in joining different materials. Self-piercing rivet(SPR) and adhesive bonding, however, are good alternatives to resistance spot welding. This paper is concerned with the crushing test of double hat-shaped member made by resistance spot welding, SPR and adhesive bonding. Various parameters of crashworthiness are analyzed and evaluated. Based on these results, the applicability of SPR and adhesive bonding are proposed as an alternative to resistance spot welding.

• 한국정밀공학회지
• /
• 제20권10호
• /
• pp.177-182
• /
• 2003

The front-end side members of automobiles absorb most of the energy in a case of 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/min) was conducted by using UTM for form different types of members which have different cross section shapes; single hat, single cap, double cap, and double hat. The single hat shaped section member has the typical standard section, which the double hat shape section has a symmetry in the center to have more stiffness. As a result of the test, the energy absorbing characteristic was analyzed for different section shapes. It turned out that the change of section shape influence the absorbing energy, the mean collapse load and the maximum collapse load, and the relation between the change of section shape and the collapse mode.

• 한국자동차공학회논문집
• /
• 제13권4호
• /
• pp.129-134
• /
• 2005

There is a strong industrial demand for the development of light-weight vehicle to improve fuel efficiency and dynamic performance. The effective method of achieving the weight reduction is to use low-density materials such as aluminum and magnesium. In applying these materials to the vehicle, it is often required to join dissimilar materials such as aluminum and steel. However, conventional joining method, namely resistance spot welding cannot be used in joining dissimilar materials. Self·piercing rivet(SPR) and adhesive bonding is a good alternative to resistance spot welding. In this study, the impact test of double hat-shaped member made by resistance spot welding, SPR and adhesive bonding was performed. As a result, various parameters of crashworthiness were analyzed and evaluated. Also, the applicability of SPR and adhesive bonding as an alternative to resistance spot welding was suggested.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1549-1552
• /
• 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.