• 한국군사과학기술학회지
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• 제7권3호
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• pp.11-20
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• 2004

In this paper, the acceptance criteria(Striking Velocities) for the A12519 weldments have been developed. Dynamic impact simulation of A12519 plate was achieved by using LS-DYNA, and predict the projectile velocity and the crack length. Also, Ballistic impact tests of A12519 plate have been performed, and compared with analysis results. Critical velocities of A12519 plate were acquired respectively, and striking velocities of A12519 weldments were calculated. Present work data will be used by basic data in ballistic impact test for A12519 weldments.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.770-775
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• 2001

Steel bar breaking system is a component of a sled test system for automobile crashworthiness. It is a recent idea for the sled test. In a sled test, a crash pulse is given as a input made from a real test. The steel bar breaking system is designed to generate a certain crash pulse. Orthogonal arrays from design of experiments (DOE) are employed. The factors of the array are panel thickness and the number of steel bars, and the levels are candidate values of them. A simulation is utilized for the crash analysis. A commercial system called LS/DYNA3D is adopted. A test system is designed based on the results.

• 한국기계가공학회지
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• 제16권4호
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• pp.119-126
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• 2017

High-precision wire is one of the most important components of lead production. However, no studies have been performed on the dimensional tolerance of these wires, and their capabilities have been deduced through trial and error. Therefore, PIANO, a commercial PIDO tool, was used to systematically determine the optimal parameters for stress minimization. The values obtained from the optimum design were modeled and analyzed using LS-Dyna, a finite element analysis program. Maximum stress was reduced by about 10% compared to its initial values, and the wire now satisfies dimensional tolerance ($10{\mu}m$).

• 소성∙가공
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• 제8권3호
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• pp.221-221
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• 1999

Warm deep drawability in a square cup drawing was investigated using a newly developed high-strength steel sheet with retained austenite that was transformed into martensite during formation. For this investigation, six different temperatures between room temperature and 250℃, and five different drawing ratios ranging from 2.2 to 2.6 were considered. The results showed that the maximum drawing force and the drawing depth were affected by the change in temperature, and a more stable thickness strain distribution was observed at elevated temperatures. However, blue shortness occurred at over 200℃. FEM analysis using the LS-DYNA code was used to compare the experimental results with the numerical results for the thickness strain distribution.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.406-410
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• 2006

Topology optimization of improved passive shock isolator by controlling its force-deflection relation is proposed. And the final design which is optimized using topology optimization is obtained using shape optimization. The proposed methods are applied to a numerical example using two dimensional-axisymmetric condition. And the performance of finally optimized design is verified through transient analysis using LS-DYNA. The ballistic shock isolator model is developed as a result of topology optimization. The optimized design has more improved shock absorbing capability comparing to the linear shock isolator by about 20%.

• Structural Engineering and Mechanics
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• 제75권5호
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• pp.607-620
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• 2020

A numerical study is carried out to assess the dynamic response and damage level of one- and two-way reinforced concrete (RC) panels subjected to explosive loads by using finite element LS-DYNA software. The precision of the numerical models is validated with the previous experimental test. The calibrated models are used to conduct a series of parametric studies to evaluate the effects of panel wall dimensions, concrete strength, and steel reinforcement ratio on the blast-resistant capacity of the panel under various magnitudes of blast load. The results are used to develop pressure-impulse (P-I) diagrams corresponding to the damage levels defined according to UFC-3-340-02 manual. Empirical equations are proposed to easily construct the P-I diagrams of RC panels that can be efficiently used to assess its safety level against blast loads.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.99-106
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• 2001

NHTSA has been conducting biomechanical studies to reduce inujuries sustained sustained during automotive collision. Furthermore, NHTSA added the regulation to the FMVSS 201, limiting the equivalent HIC(Head Injury Criterion) value under 1000. In the presont work, a methodology was developed for the optimum design of the A-pillar trim with rib-structures. The design variables for the rib-strucrures were the transverse spacing, the longitudinal spacing, and the thickness. The required sets of the design varibles were decided based on the design of experiments. The head impact simulations were carried out using the LS-DYNA3D, and the HIC(d) values were computed using the resulrs of the head impact simulation. The objective function was constructed using the response surface methed (RSM). When the obtained optimum values were not inside the region of interest, the design proceduers were repeated by changing the region of interest. Finally, an A-pillar trim with rib-structures, which resulred in HIC(d) value under 850 for 15 mph head-trim impact, was developed.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.198-204
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• 2004

Dynamic fracture is investigated in plate applied by impacting bar. Numerical simulations of the experiments are made by using a finite element method(FEM) code, LS-DYNA. The eroding surface-to-surface contact allows between impacting bar and impacted plate. The occurrence of hourglass deformations in an analysis can invalidate results and hourglass energy is minimized to obtain the good accuracy of result. Total, internal and kinetic energies, von Mises plastic stress and X,Y,Z velocities of impacting bar are analyzed in this study.

• 한국자동차공학회논문집
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• 제15권4호
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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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• 제30권5호
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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.