• 자동차안전학회지
• /
• 제16권2호
• /
• pp.60-66
• /
• 2024

Computer simulation significantly reduces the high costs associated with actual crash tests and is expanding due to its ability to analyze various test results quantitatively that are difficult to measure in real tests. Research on evaluation technologies is limited according to the finite element analysis, which aims to replace structural verification testing. In this study, considerations for virtual crash tests were derived, and the validity of the zero-energy mode (hourglass mode) was analyzed as part of the considerations for validating the results of vehicle crash simulations. The study reflects on the considerations for virtual crash tests and the variation in hourglass coefficient values affects the occurrence of the hourglass mode. As the hourglass coefficient changes, the maximum hourglass energy reaches over 5% of the maximum internal energy, necessitating a conservative review. A comprehensive study of the maximum hourglass energy is required, considering additional analysis results for various models and collision conditions.

• Composites Research
• /
• 제28권2호
• /
• pp.65-69
• /
• 2015

본 연구는 도로시설물에 적용될 수 있는 복합재료 지주구조에 대하여 실차 차량 충돌 시뮬레이션을 통한 동적 특성을 다룬다. 다양한 차량 충돌 속도에 대한 서로 다른 복합재료 물성의 영향을 LS-DYNA 유한요소 프로그램을 사용하여 분석하였다. 본 연구에서는 LS-DYNA 프로그램을 적용하여 기존의 강재 지주구조에 대한 유한 요소해석을 다양한 복합재료로 구성된 지주구조로 확장하여 적용하였다. 탑승자 안전성 평가를 기반으로 다양한 매개변수에 대한 수치해석 결과는 지주와 차량에서 발생하는 내부에너지를 비교 분석하여 규명하였다.

• 한국산학기술학회논문지
• /
• 제12권4호
• /
• pp.1552-1558
• /
• 2011

본 논문에서는 알루미늄 폼을 사용한 자동차 범퍼 빔을 설계하고 충돌해석을 수행하였다. 해석모델은 B형 단면 구조를 갖는 실제 크기의 범퍼 빔이다. 저속 정면충돌 시 알루미늄 범퍼 빔의 변형량 및 내부 에너지 거동을 예측할 수 있는 ANSYS AUTODYN을 이용하였다. 7075-T6 알루미늄 합금을 사용하여 철강 재질의 빔보다 55 %의 중량 감소를 얻을 수 있었으며 알루미늄 폼을 사용한 범퍼 빔의 변형량은 철강 빔과 비슷하지만 충돌에너지의 감소가 더 큰 것을 확인할 수 있었다. 또한, 알루미늄 폼의 완충보다는 50 % 충진 시 충돌에너지 흡수가 더 좋았다.

• 한국자동차공학회논문집
• /
• 제10권4호
• /
• pp.181-191
• /
• 2002

The homogenization method is applied to maximize crash energy absorption for a given volume. Optimization analysis off closed-hat type example problem is conducted with different impact velocities and thicknesses. The results show that the bending-type deformation for the original design is changed to the folding-type deformation for a new design with a hole, which is partly due to the increase of the crash energy absorption for the new design. Dynamic mean crushing loads of the original and new design are compared with those by the theoretical equation by Wierzbicki. It shows that the dynamic mean crushing loads of new designs are very close to those by Wierzbicki's equation.

• 한국자동차공학회논문집
• /
• 제12권5호
• /
• pp.94-100
• /
• 2004

In order to improve the frontal crash performance of an Aluminum Space Frame Vehicle, this presents a systematic optimal design process to maximize the crush energy absorption capacity of side-members while satisfying the maximum displacement constraint. In this study, five design types are studied for selecting a good collapse initiator. Then, for the selected collapse initiator type, 7 design variables are defined to represent cross section shape, thickness and bead interval. The systematic optimization processor, R-INOPL uses DOE, RSM and numerical optimization techniques. R-INOPL uses only 14 analyses to solve the 7 design variable optimization problem the final design can improve 103.9% of the internal energy and reduce 13.9% of the maximum displacement.

• 한국자동차공학회논문집
• /
• 제9권3호
• /
• pp.190-200
• /
• 2001

The homogenization method is applied to maximize crash energy absorption for a given volume. To obtain the best combination of optimizing factors by resizing and threshold algorithms for an example problem, the sensitivity analysis has been performed using design of experiments. The results show that very little interaction among optimizing factors is found. Optimization analysis of several combination of factors is conducted; and the orignal design and a new design with holes for an example problem are compared for crash energy absorption.

• 한국정밀공학회지
• /
• 제21권4호
• /
• pp.132-139
• /
• 2004

The open section members have been used as the members of vehicle such as automotives, airplanes and trains. When vehicles are crashed, these members have absorption of the energy and it is necessary for retainment of the survival space, and as the result, the prediction for the displacement of members in this case of the crash of vehicles is very important. The displacements of members in this case of the crash of automotives show combined aspect of both axial collapse and bending collapse. In the rollover accident when bending collapse happen, the collapse of each members is progressed by the plastic hinge which made from bending moment, and therefore the research for the behavior of members under bending moment after collapse is necessary to determine the internal energy which the members can absorb and the deformed shapes of the members on the step of design. In this paper, the characteristics of bending collapse at the members of the open cross-section were studied with experiment and numerical analysis. We made a comparative studied of the result of the experiment, and changed the axis according to the parallel-axis theorem.

• 한국자동차공학회논문집
• /
• 제10권3호
• /
• pp.111-122
• /
• 2002

European offset impact analysis of an electric vehicle was done using the robust design method. Section properties of some of the vehicle structure components which influence the european offset impact characteristics were chosen as the main factors fur the design. Eight factors were considered for the analysis: one with two level and seven with three level combinations comprising the L$\_$18/(2$^1$$\times$3$\^$7/) orthogonal array. It is shown that the sensitivities of the factors and the best combination of the factors can be obtained. One of the noteworthy results is that the design with the lower stiffness of the front components of engine room than the rear components can absorb more crash energy. Also it is shown that there exist interactions between some of factors considered.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집A
• /
• pp.224-229
• /
• 2000

This paper describe a (mite element computer simulation of a absorption system using full scale car crash test. The full scale test selected for this study is a 80kmh frontal, side and 25% offset impact of a 1993 Ford Taurus vehicle into a absorption system. This absorption system has external rubber and internal steel pannel. This simulation has completed for decision of these components energy absorption performance. Dynamical performance of this system and movement are obtained from this simulation. and then We can appreciate the safety of passenger from measure the vehicle C.G's acceleration.

• 천문학회지
• /
• 제36권3호
• /
• pp.111-121
• /
• 2003

In order to explore the cosmic ray acceleration at the cosmological shocks, we have performed numerical simulations of one-dimensional, plane-parallel, cosmic ray (CR) modified shocks with the newly developed CRASH (Cosmic Ray Amr SHock) numerical code. Based on the hypothesis that strong Alfven waves are self-generated by streaming CRs, the Bohm diffusion model for CRs is adopted. The code includes a plasma-physics-based 'injection' model that transfers a small proportion of the thermal proton flux through the shock into low energy CRs for acceleration there. We found that, for strong accretion shocks with Mach numbers greater than 10, CRs can absorb most of shock kinetic energy and the accretion shock speed is reduced up to $20\%$, compared to pure gas dynamic shocks. Although the amount of kinetic energy passed through accretion shocks is small, since they propagate into the low density intergalactic medium, they might possibly provide acceleration sites for ultra-high energy cosmic rays of $E\ll10^{18}eV$. For internal/merger shocks with Mach numbers less than 3, however, the energy transfer to CRs is only about $10-20\%$ and so nonlinear feedback due to the CR pressure is insignificant. Considering that intracluster medium (ICM) can be shocked repeatedly, however, the CRs generated by these weak shocks could be sufficient to explain the observed non-thermal signatures from clusters of galaxies.