• 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.

• 한국자동차공학회논문집
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• 제18권2호
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• pp.104-113
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• 2010

Domestic insurance claims were statistically investigated to analyze the elderly driver's accident patterns and injury types in side impact crashes. Medical treatment records and accident vehicle damage photos have been surveyed for 5,419 cases. The results of our statistical analysis showed that the thorax injury risk of the elderly drive group is 8.8 and 4.0 times higher than that of the young and middle age group respectively. Diagnosis showed that most thorax injuries were caused by rib fracture. The head injury risk of the elderly female driver group seemed to be higher than that of the younger female driver group, however, statistical test has not been conducted because of the lack of number of samples for elderly female accident.

• 대한기계학회논문집
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• 제17권2호
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• pp.237-247
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• 1993

본 연구에서는 CFRP 적층재를 구조재료로 사용할 경우 우수한 인장강도를 갖 지만, 충격하중에 취약한 특성을 갖기 때문에 구조안정성에 관한 큰 문제의 하나로 충 격손상을 받은 적층판의 잔류 압축강도가 현저히 저하되는 것이 문제점으로 지적되어 왔다.특히, 충격손상에 의한 압축강도의 저하는 인장강도보다 압축강도에 중점을 두는 항공기의 강도설계에서 중요한 문제가 되므로, 저속충격에 의한 복합재료 구조체 의 충격파괴의 문제를 잘 이해하는 것이 요구된다. 지금까지의 연구에 의하면 CFRP 복합적층재의 손상은 주로 층간박리현상과 손상역의 크기변화를 실험적으로 고찰하였 다.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.924-932
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• 2004

In this study, the axial collapse tests were performed under either static (or quasi-static) or impact loads with several collapse velocities based on the expectation that para-closed sections of the front-end side members (spot welded hat and double hat shaped section members) would show quite different collapse characteristics from those for seamless section. The test results showed that both of the hat and double hat shaped section members failed in the stable sequential collapse mode in the static or quasi-static collapse tests, while the double hat shaped section members underwent the unstable collapse mode especially when the impact velocity is high. The mean collapse loads in the hat shaped section members increase with collapse velocity for all the cases of the static, quasi-static, and impact collapse tests. In the double hat shaped section members, however, the mean collapse loads decrease with increase in collapse velocity in the impact tests.

• 오토저널
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• 제15권5호
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• pp.15-21
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• 1993

본 연구에서는 자동차 차체의 경량화 방안으로서 섬유강화 복합재료를 이용한 충격흡ㅅ수 구조재인 Side Member(측면부재)의 응용을 위한 시뮬레이션용 Box Tube의 충돌에너지 흡수특성 및 거동에 대해서 기존 금속 측면부재와 비교하여 논의해 보고자 한다. 1. 금속 충돌흡수 부재의 붕괴거동. 2. 복합재료 충격흡수부재의 붕괴거동.

• 한국소음진동공학회논문집
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• 제16권10호
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• pp.1036-1043
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• 2006

Damping materials for reducing heavy-weight floor impact noise in reinforced concrete structures were tested in apartment buildings. The effect of damping materials and an impact isolator were compared with an on-site experiment conducted in a high-rise apartment building. The loss factor of damping material analyzed more than 2 times than rubber to $1.5{\sim}2.3$, could know that Damping layer has excellent attenuation performance in side of vibration reduction. The results showed that the resonance frequency increased but vibration acceleration level decreased when the damping materials were used. The heavy-weight impact sound levels of the structure decreased substantially at 63 Hz, whereas the sound levels of the structure with the impact isolator increased.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.295-300
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• 2002

To establish an optimum condition in the surface treatment and curing process will be an important parameters for the fabrication of multilayered hybrid composite materials, A17075/CFRP (CARALL : carbon fiber reinforce aluminum laminates). Effects of carbon fiber direction and thickness variation in tensile strength were investigated. And impact damage behavior of carbon fiber reinforce plastic (CFRP) and CARALL were investigated also, it was found that a partial stress increase in order of epoxy adhesive, A17075, CFRP. And the partial stress of CFRP carried out a great portion of applied stress. The impact damage resistance of CARALL was higher than that of CFRP. This is because both side Al sheet of CARALL absorb a great of impact damage.

• 소성∙가공
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• 제30권5호
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• pp.236-241
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• 2021

This study describes the cold stamping process design procedure to secure the formability and dimensional accuracy of the automotive structural component fabricated by 1.5GPa grade ultra-high strength steel sheet. The target product is selected as the front side rear lower member which is the most important energy absorption part in the frontal impact condition. To secure the product quality, an intermediate product shape is added while considering the low elongation and high strength characteristics of 1470Mart. The sequential optimization procedure of the intermediate product shape, the fine dimensional quality is then achieved without any crack or wrinkling. The cold stamping method with ultra-high strength steel sheets is validated by conducting the die tryout of the front side rear lower member.

• 한국소음진동공학회논문집
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• 제20권4호
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• pp.338-347
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• 2010

Heunginjimun designated as a Treasure No.1 is a two-story wooden structure with 5 bay and 2 bay in its front and side views, respectively. This paper presents an investigation on vibration characteristics of Heunginjimun through both ambient vibration and impact hammer tests. Ambient vibration test was performed to identify the natural frequency of Heunginjimun from the spectrum analysis of time history. Impact hammer test was undertaken to find the frequency of Heunginjimun which is affected by the surrounding traffics and to verify the reciprocal principle for the wooden structural system. Ambient vibration test results of Heunginjimun showed that the natural frequencies in two principal axes 1.5 Hz and 1.1 Hz, respectively. It was confirmed from impact hammer tests for a ground that the frequency of 4.2 Hz is caused by the traffics surrounding Heunginjimun. It was also observed that from the impact hammer test results between two locations in Heunginjimun that the transfer functions measured from two corresponding locations coincided well with each other. This result shows that the wooden structural system is globally linear, and the reciprocal principle is established.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.108-113
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• 2005

The damageability and repairability of similar platform type vehicles could be very concerned with design optimization. In all the vehicles crash tested, small size passenger vehicles were weakness in aspect of damageability and repairability. The most critical area appears to be repair cost considering that parts cost is the largest portion of total repair cost segments. Besides repair cost, attaching method of front sidemember and subframe are placed special importance for impact energy absorption and damageability and repairability. So in order to improve damageability and repairability of vehicle structure and body component of the monocoque type passenger vehicles, the end of front side member and front back beam should be designed with optimum level and to supply the end of front side member as a partial condition approx 300mm. The effectiveness of design concept on the 40% offset frontal impact characteristics of the passenger vehicle structure is investigated and summarized.