• 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).

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.17-20
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• 2002

Recently tube hydroforming technology has been one of the most important technology in automotive industry in the point of saving weight and high quality for collision accidents. In this paper, experimental studies for axial compression tests of hydroformed tubes are performed to investigate the collapse absorption characteristics. The collapse absorption abilities are discussed and compared for as-received, hydroformed, and press formed tubes.

• 한국자동차공학회논문집
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• 제1권3호
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• pp.118-126
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• 1993

Static and dynamic crushing behaviors of composite box tube show the difference with those of metal tube. This paper investigates the characteristics of static and dynamic crushing test which were conducted to characterize the energy absorption and collapse mode of composite box tubes. Sixteen kinds of tube specimens were fabricated from[0/90] woven Glass/Epoxy fabric and autoclave cured. Axial crushing tests were performed using Instron and Dynatup Impact Tester. It is shown that collapse mode and energy absorption capacity can vary according to the aspect ratio, length, loading rate, lay-up direction of fabric, and trigger geometry of the composite box tube.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.50-56
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• 2005

Aluminum member absorbs energy by stable plastic deformation under axial loading. While CFRP(Carbon Fiber Reinforced Plastics) member absorbs energy by unstable brittle failure but its specific strength and stiffness is higher than those of aluminum member. In this study, for complement of detects and synergy effect by combination with the advantages of each member, the axial collapse tests were performed for aluminum CFRP members which are composed of aluminum members wrapped with CFRP outside aluminum circular members. Based on the respective collapse characteristics of aluminum and CFRP members, crushing behavior and energy absorption characteristics were analyzed for aluminum CRRP members which have different CFRP fiber orientation angle and thickness Test results showed that aluminum CFRP members supplemented the unstable brittle failure of CFRP members due to ductile nature of inner aluminum members. It turned out that the CFRP fiber orientation angle and thickness influence energy absorption capability together with the collapse mode of the members.

• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1085-1098
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• 2014

Plastic mechanism analysis of structures subjected to large deformation has long been used in order to determine collapse mechanisms of steel structures, and the energy absorbed in plastic deformation during such collapses. In this paper the technique is applied to vehicle roof structures that undergo large plastic deformation as a result of rollover crashes. The components of such roof structures are typically steel spot-welded hat-type sections. Ten different deformation mechanisms are defined from investigations of real-world rollover crashes, and an analytical technique to determine the plastic collapse load and energy absorption of such mechanisms is determined. The procedure is presented in a generic manner, such that it may be applied to any vehicle structure undergoing a rollover induced collapse. The procedure is applied to an exemplar vehicle, in order to demonstrate its application in determining the energy absorbed in the deformation of the identified collapse mechanisms. The procedure will be useful to forensic crash reconstructionists, in order to accurately determine the initial travel velocity of a vehicle that has undergone a rollover and for which the post-crash vehicle deformation is known. It may also be used to perform analytical studies of the collapse resistance of vehicle roof structures for optimisation purposes, which is also demonstrated with an analysis of the effect of varying the geometric and material properties of the roof structure components of the exemplar vehicle.

• 한국공작기계학회논문집
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• 제15권6호
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• pp.114-120
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• 2006

Front-end side members of vehicles are structures with the greatest energy absorbing capability in a front-end collision of vehicles. This paper was undertaken to analyze the energy absorption characteristics of spot welded hat and double hat-shaped section members under the axial collapse. The experiments were performed with respect to the various collapse velocities. It was expected that para-closed sections would show collapse characteristics which be quite different from those of perfectly closed sections. The collapse velocities were selected as follows: the velocities in the hat-shaped section members were 0.00017m/sec, 0.017m/sec, 4.7m/sec, 6.5m/sec, 6.8m/sec, 7.2m/sec, and 7.3m/sec those in the double hat-shaped section members were 0.00017m/sec, 0.017m/sec, 6.5m/sec, 6.8m/sec, 7.2m/sec 7.3m/sec, and 7.9m/sec. In the program system presented in this study, an explicit finite element code, LS-DYNA3D, is adopted for simulating complicated collapse behavior of the hat and double hat-shaped section members under the same condition of the collapse test. The validity of simulation was confirmed by the comparison between the simulation result and the collapse experiment.

• Structural Engineering and Mechanics
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• 제54권6호
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• pp.1245-1266
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• 2015

In this research, the cylindrical absorber made of expanded metal sheets under impact loading has been examined. Expanded metal sheets due to their low weight, effective collapse mechanism has a high energy absorption capacity. Two types of absorbers with different cells angle were examined. First, the absorber with cell angle ${\alpha}=0$ and then the absorber with angle cell ${\alpha}=90$. Experimental Study is done by drop Hammer device and numerical investigation is done by finite element of ABAQUS software. The output of device is acceleration-time Diagram which is shown by Accelerometer that is located on the picky mass. Also the output of ABAQUS software is shown by force-displacement diagram. In this research, the numerical and experimental study of the collapse type, force-displacement diagrams and effective parameters has been investigated. Similarly, the comparison between numerical and experimental results has been observed that these results are matched well with each other. From the obtained results it was observed that the absorber with cell angle ${\alpha}=0$, have symmetric collapse and had high energy absorption capacity but the absorber with cell angle ${\alpha}=90$, had global buckling and the energy absorption value was not suitable.

• 한국정밀공학회지
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• 제18권11호
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• pp.34-41
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• 2001

This study is to investigate the energy absorption characteristics of CFRP(Carbon-Fiber Reinforced Plastics) tubes on static and dynamic tests. Axial static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine) and dynamic compression tests have been utilized using an vertical crushing testing machine. When such tubes are subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that could control the crushing process. The collapse characteristics and energy absorption have been examined for various tubes. Energy absorption of the tubes are increased as changes in the lay-up which may increase the modulus of tubes. The results have been varied significantly as a function of ply orientation and interlaminar number.

• 한국생산제조학회지
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• 제21권4호
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• pp.588-592
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• 2012

This study concentrates the effect of hybridisation on the collapse mode and energy absorption for composite cylinders. The static collapse behavior of laminated(Al/CFRP/GFRP) circular-cylindrical composite shell under quasi-static axial compressive load has been investigated experimentally. Eight different hybrids of laminated(Al/CFRP/GFRP) circular-cylindrical composite shell were fabricated by autoclave. Eight types of composites were tested, namely, Al/carbon fiber/epoxy, Al/glass fiber/epoxy, Al/carbon-carbon-glass/epoxy, Al/carbon-glass-carbon/epoxy, Al/carbon-glass-glass/epoxy, Al/glass-glass-carbon/epoxy, Al/glass-carbon-glass/epoxy and Al/glass-carbon-carbon/epoxy. Collpase modes were highly dominated by the effect of hybridisation. The results also showed that the hybrid member with material sequence of Al-glass-carbon-carbon/epoxy exhibited good energy absorption capability.

• 한국생산제조학회지
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• 제19권5호
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• pp.603-608
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• 2010

In this study, one type of circular shaped composite tube was used, combined with reinforcing foam and without foam. Furthermore, CFRP(Carbon Fiber Reinforced Plastic) circular member manufactured from CFRP prepreg sheet for lightweight design. CFRP is an anisotropic material which is the most widely adapted lightweight structural member. The crashworthy behavior of circular composite material tubes subjected to static axial compression under same conditions is reported in this paper. Test was executed in order to compare the results to the energy absorption and collapse shape. The collapse mode during the failure process were observed and analyzed. The behavior of polymeric foams to the tubes crashworthiness were also investigated. According to the experimental results, specimens filled with foam are higher total energy absorption than the other specimens not filled with the foam.