• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.1-9
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• 2007

This study proposes a methodology to assess the traffic safety benefits of technical regulation for pedestrian leg. Traffic safety benefit is defined as the injury reduction in this study. Actual accident analysis and simulation experiments using LS-Dyna3d are conducted to establish statistical models for developing the methodology. The relationship between collision speed and parameters of the regulation is explored. An application example of the proposed methodology is also presented for more comprehensive understanding. It is believed that the proposed methodology would be greatly utilized in developing various technologies and policies to protect pedestrian.

• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.462-469
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• 1998

A package to transport high-level radioactive materials is required to withstand normal transport and hypothetical accident conditions pursuant to the IAEA and domestic regulations. The package should maintain the structural safety not to release radioactive material in any condition. The structural safety of the package has been evaluated by tests using proto-type or scaled-down models, however, the method by analysis is gradually utilized due to recent advancement of computers and computer codes. In this paper, to evaluate the structural safety of a radioisotope package of the KAERI, the three dimensional impact analyses under 9m free drop and 1m puncture were performed with an explicit finite-element code, the LS-DYNA3D code. The maximum stress intensity on each part was calculated and the structural safety of the package was evaluated in accordance with the regulations.

• Journal of Power System Engineering
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• v.14 no.5
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• pp.24-29
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• 2010

TFT-LCD module with thin, small and layered structure makes its shock analysis very difficult and complicated. As TFT-LCD becomes more thinner, it is more difficult to assure its required shock resistance. Recently, the drop/impact simulation using the commercial explicit dynamic analysis software such as LS-DYNA3D is actively applied to assess the shock characteristics of TFT-LCD. In this study, the effects of analysis parameters and design modifications in the drop/impact simulation are carefully studied. the reliability of the present analysis results can be assured through the experimental verification.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.351-358
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• 2001

In this study, for the investigation of effects of several parameters, such as fluid mesh boundary size, cylinder or block shape, dimensions of depth, breadth and length at free suface, and fluid mesh element size to the depth direction on a reliable shock response of finite element model under underwater explosion with consideration of the bulk cavitation analysis of a simplified surface ship was carried out using the LS-DYNA3D/USA code. The shock responses were not much affected by the fluid mesh parameters. The computational time was greatly dependent on the number of DAA boundary segments. It is desirable to reduce the DAA boundary segments in the fluid mesh model, and it is not necessary to cover the fluid mesh boundary to or beyond the bulk cavitation zone just for the concerns about an initial shock wave response. It is also the better way to prefer cylinder type of the fluid mesh model to the block one.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.293-298
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ, But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations. In the result it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.1-7
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• 2003

The front-end side members of vehicles(spot welded hat and double hat shaped section members) absorb most of the impact energy in a case of front-end collision. In this paper, specimens with various spot weld pitches have been tested with a high impact velocity of 7.19m/sec(impact energy of 1034J). The axial impact collapse simulation on the sections has been carried out to review the collapse characteristics of these sections, using an explicit finite element code, LS-DYNA3D. Comparing the results with experiments, the simulation has been verified; the energy absorbing capacity is analyzed and an analysis method is suggested to obtain exact collapse loads and deformation collapse modes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.766-771
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• 2001

The package used to transport radioactive materials, which is called by cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than one for test. the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors. the results depends on how users apply the codes and it can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop and the puncture condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique for the free drop impact test of the cask and found several vulnerable cases to errors. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.737-741
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• 2000

Portable communication devices such as laptop computers suffer impact-induced failure in their usage. Drop/impact performance of these products is one of important concerns of product design. Because of the small size of this kind of electronics products, it is very expensive, time-consuming and difficult to conduct drop tests to directly detect the failure mechanism and identify their drop behaviors. Finite element analysis provides a vital, powerful vehicle to solve the problems. The models are created with HYPERMESH, and the analysis is carried out with LS-DYNA3D. The analysis is focused on HDD impact behavior in acceleration peak values.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.461-466
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ. But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations In the result, it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.711-719
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• 2016

In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.