• Journal of the KSME
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• v.35 no.8
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• pp.691-697
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• 1995

인체 머리부분의 충격력이 가했을 때 어떠한 상해가 발생할 것인가에 대하여 수치해석적인 접 근을 시도하였다. 복잡한 생체구조의 단순화, 비선형적인 재료 특성으로 인하여 해석 결과는 정 량적인 정확성보다 정성적인 경향성에 보다 큰 의미가 있다고 할 수 있으며, 앞으로 개선할 여 지가 많다고 할 수 있다. 또 의학적인 부분에 관한 기초지식이 필요하기 때문에 의학계의 조건 또는 의학계와의 공동 연구가 요망된다고 하겠다. 해석 결돠의 검증은 과거에는 주로 사체 및 동물 심험에 의하여 행해졌으나 현재에는 사체 실함이 금지되어 있고, 동물(원숭이, 개, 돼지 등 )을 이용한 실험도 동물 보호단체의 반발로 여의치 않은 형편이다. 현재는 교통사고 등에서의 사체 부검 및 사고 상황의 역추적에 의해 생체 실함을 대신할 데이터가 마련되고 있으나, 정확한 사고 상황을 파악하는 것 자체가 또한 어려운 작업이다. 그래서 각 나라에서 일부분씩 가지고 있는 생체에 대한 데이터를 모아 전세계적인 데이터 베이스를 만들어 공유하려는 작업이 진행 되고 있다. 이렇게 실험이 불가능하거나 어려운 상황하에서는 수치 시뮬레이션이 주요한 해석 수단이 될 수 있을 것이라 생각된다.

• Advances in aircraft and spacecraft science
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• v.2 no.4
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• pp.391-401
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• 2015

Crashworthiness design and certification have been and will continue to be the main concern in aviation safety. The effects of roll angles on fuselage section crashworthiness for typical civil transport category aircrafts were investigated. A fuselage section with waved-plates under cargo floor is suggested, and the finite element model of fuselage section is developed to simulate drop test subjected to 7 m/s impact velocity under conditions of 0-deg, 5-deg, 10-deg and 15-deg roll angles, respectively. A comparative analysis of failure modes, acceleration responses, and energy absorption of fuselage section under various conditions are given. The results show that the change of roll angles will significantly affect fuselage deformation, seat peak overloads, and energy absorption. The crashworthiness capability of aircraft can be effectively improved by choosing appropriate landing way.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.604-608
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• 2010

This paper proposed a new 2D multibody dynamic modeling technique to analyze overriding behavior taking place during train collision. This dynamic model is composed of nonlinear spring, damper and mass by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model of rollingstock, collision energy absorption capacity, acceleration of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we choose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3D finite element analysis, and established a 2D multibody dynamic model. This 2D dynamic model was suggested to describe the collision behavior of 3D Virtual Testing Model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.141-146
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• 1992

본 연구에서는 먼저 낙하 충격을 받는 전자 제품을 수학적인 모델링을 행하 므로서 낙하 충격시 제품이 받게되는 충격력을 정량화하였고, 전자 제품내 많은 부품들의 낙하충격에 대한 동특성해석의 일환으로 핵심 부품인 PCB(printed circuit board)를 해석하였다. PCB 해석을 위하여 유한요소법을 사용하였고, PCB에 작용하는 half-sine pulse의 속도 변화에 다른 가속도 응 답 및 최대 충격가속도, 주기의 변화에 다른 PCB의 가속도 응답을 해석하였 다. 제시된 해석 기법은 낙하충격에 대비한 적절한 electric component의 layout및 최적의 PCB 취부조건등의 결정을 가능케 함으로써, 설계단계에서 낙하 충격을 고려한 PCB설계가 될 수 있도록 그 활용 방안을 제시하였고 반복된 낙하충격 실험을 줄일 수 있으므로 경비 절감 및 개발 소요기간도 절감할 수 있다.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.464-468
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• 2008

In most of the passenger side airbag door in hard type IP today is designed with invisible tear-seam line. In order to design the tear-seam invisible, the tear-seam must be designed with required RWT (residual wall thickness) that is just thick enough to be broken by the PAB pressure on deployment and not by other surrounding impact forces. Hence, keeping the right optimum opening force is very important, and finding the right RWT became the key in designing the tear-seam. The study conducted in this paper describes the search for the optimum RWT around the tear-seam by using finite element method and the optimum RWT is suggested for milling type tear-seam having V-shape cross-section.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.302-306
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• 2006

In this study, we analyzed the influence of electrical pole by FEM(Finite Element Method) and developed protective system by designing and interpreting protective system for electrical pole when abnormal strength worked on messenger wire. Protective system did not shed messenger wire under wind pressure and discontent load but did assign a part to preventing rupture of electrical pole through automatically shed messenger wire over fixed strength. Structure of protective system analysis by FEM and prove property by measuring tensile strength for practical product.

• Proceedings of the Korean Reliability Society Conference
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• 2004.07a
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• pp.129-137
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• 2004

This paper presents an accelerated life test for burnout of tungsten filament of incandescent lamp. From failure analyses of field samples, it is shown that their root causes are local heating or hot sports in the filament caused by tungsten evaporation and wire sag. Finite element analysis is performed to evaluate the effect of vibration and impact for burnout, but any points of stress concentration or structural weakness are not found in the sample. To estimate the burnout life of lamp, an accelerated life test is planned by using quality function deployment and fractional factorial design, where voltage, vibration, and temperature are selected as accelerating variables. We assumed that Weibull lifetime distribution and a generalized linear model of life-stress relationship hold through goodness of fit test and test for common shape parameter of the distribution. Using accelerated life testing software, we estimated the common shape parameter of Weibull distribution, life-stress relationship, and accelerating factor.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.1064-1081
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• 2014

This paper presents a numerical analysis of slamming and whipping using a fully coupled hydroelastic model. The coupled model uses a 3-D Rankine panel method, a 1-D or 3-D finite element method, and a 2-D Generalized Wagner Model (GWM), which are strongly coupled in time domain. First, the GWM is validated against results of a free drop test of wedges. Second, the fully coupled method is validated against model test results for a 10,000 twenty-foot equivalent unit (TEU) containership. Slamming pressures and whipping responses to regular waves are compared. A spatial distribution of local slamming forces is measured using 14 force sensors in the model test, and it is compared with the integration of the pressure distribution by the computation. Furthermore, the pressure is decomposed into the added mass, impact, and hydrostatic components, in the computational results. The validity and characteristics of the numerical model are discussed.

• Korean Journal of Materials Research
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• v.27 no.1
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• pp.19-24
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• 2017

This paper is concerned with a test method that can be used to investigate the parameters of the Johnson-Cook constitutive model. These parameters are essential for accurately analyzing material behavior under impact loading conditions in numerical simulation. Ti-6Al-4V alloy (HCP crytal structure) was used as a specimen for the experiments. In the $10^{-3}-10^3/s$ strain rate range, three types of experimental methods (convention, compression and tension) were employed to compare the differences using MTS-810, SHPB and SHTB. Finite element analysis results when applying these parameters were displayed along with the experiment results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.3
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• pp.78-83
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• 2006

In this study, we analyzed the influence or electrical pole by FEM(Finite Element Method) and developed protective system by designing and interpreting protective system for electrical pole when abnormal strength worked on messenger wire. Protective system did not shed messenger wire under wind pressure and discontent load but did assign a part to preventing rupture of electrical pole through automatically shed messenger wire over fred strength. Structure of protective system analysis by FEM and prove property by measuring tensile strength for practical product.