• 한국자동차공학회논문집
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• 제8권3호
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• pp.190-197
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• 2000

A graphic vehicle modeling pre-processing program and a visualization post-processing program have been developed for AutoDyn7, which is a special program for vehicle dynamics. The Rapid-App for GUI(Graphic User Interface) builder and the Open Inventor for 3D graphic library have been employed to develop these programs in Silicon Graphics workstation. A Graphic User Interface program integrates vehicle modeling pre-processor, AutoDyn7 analysis processor, and visualization post-processor. In vehicle modeling pre-processor, vehicle hard point data for a suspension model are automatically converted into multibody vehicle system data. An interactive graphics capabilities provides suspension modeling aides to verify user input data interactively. In visualization post-processor, vehicle virtual test simulation results are animated with virtual testing environments.

• 한국자동차공학회논문집
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• 제9권6호
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• pp.152-159
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• 2001

In multibody dynamic analysis including contact and impact, there are two major analysis methods, i.e., piecewise analysis and continuous analysis. Modeling of contact phenomena is mainly classified with a Kelvin-Voigt model or a model of Hertz contact model. In this paper, a contact module fur AutoDyn7 program was developed and implemented. Both the Kelvin-Voigt model and a model of Hertz contact law were developed. The process of this module is composed of contact distinction and the contact force calculation. Two examples were verified and compared to the commercial program DADS.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1878-1884
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• 2000

In multibody dynamic analysis, one of the most important problems is to reduce computation times for real time simulation. In this paper, a symbolic computation method is implemented and tested for each dynamic analysis step. Applying symbolic formulations to the vehicle dynamics program AutoDyn7, the effectiveness of the symbolic computation method is verified.

• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.730-736
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• 2000

In this paper, several tire models (Magic formula, Carpet plot, VA tire, DADS tire and STI tire) are implemented and compared. Since the STI (System Technology Inc.) tire model in the AutoDyn7 program is in a good agreement to NADSdyna STI tire model and experiment, it is selected as a reference tire model for the comparison. To compare tire models, input parameters of each tire model are extracted from the STI tire model to preserve the same tire properties. Several simulations are carried out to compare performances of tire models, i. e., bump simulation, lane change simulation, and pulse steering simulation. The performances in vehicle maneuverability are also compared with the four parameter evaluation method.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.185-191
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• 2001

In many papers, the powertrain system generally has been madeled as one-dimensional torque model. One-dimensional powertrain model may calculate the torque correctly but it does not consider the non-rotational degrees-of-freedom of the powertrain components and the interaction of these degrees-of-freedom with the vehicle body frame and suspension. To consider the non-rotational degrees of freedom, the differential is modeled as a three-dimensional rigid body in this paper. A constant velocity joint is newly formulated and a relative constraint is also formulated to model the motion transfer due to gear ratio of the differential. Implementing the proposed powertrain system in the multibody model, more detail dynamic responses can be obtained. Obtained outputs such as reaction torques on the constant velocity joint and reaction forces on the rack can be useful data in the design of a powertrain.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.649-654
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• 2000

To analyze the effects of the front and rear roll stabilizer bar, five different models of roll stabilizer bar are simulated in this paper. It is shown that the stiffness change of the roll stabilizer bar is an effective way to alter the vehicle's roll gradient. Attaching an actuator at the roll stabilizer bar the vehicle's roll gradient can be controlled within error limits.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.186-193
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• 1999

In this paper, a full vehicle model is developed to analyze toe and camber changes due to rack height variation and compliance. The AutoDyn7 program developed in G7 project is used for the computer simulation. Steady state cornering test was done to find the understeer gradient. Imposing a pulse steer input, Frequency Response Function(FRF) of yaw rate and lateral accelerations were evaluated. To verify the stability, the rhombus using four parameters is employed. Steer characteristics were evaluated by changing the rack height and the bushing lateral stiffiness. which installed between the low control arm and the chassis.

• 한국안전학회지
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• 제31권3호
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• pp.8-15
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• 2016

The purpose of this study is to design a model with the structural stability so as not to lose the operational function due to structural plastic or fail of a sliding blast door by blast pressure to this aim, a numerical simulation was performed using full-size experiments and M&S (Modeling & Simulation) of the sliding blast door. The sliding blast door ($W3,000{\times}H2,500mm$) under the blast load is in the form of a sliding type 2-way metal grill, which was applied by a design blast pressure (reflected pressure $P_r$) of 17 bar. According to the experimental results of a real sliding blast door under blast load, the blast pressure reached the sliding blast door approximately 4.3 ms after the explosion and lasted about 4.0 ms thereafter. The maximum blast pressure($P_r$) was 347.7 psi (2,397.3 kPa), it is similar to the UFC 3-340-02 of Parameter(91 %). In addition, operation inspection that was conducted for the sliding blast door after real test showed a problem of losing the door opening function, which was because of the fail of the Reversal Bolt that was installed to prevent the shock due to rebound of the blast door from the blast pressure. According to the reproduction of the experiment through M&S by applying the blast pressure measurement value of the full-size experiments, the sliding blast door showed a similar result to the full-size experiment in that the reversal bolt part failed to lose the function. In addition, as the pressure is concentrated on the failed reversal bolt, the Principal Tensile Failure Stress was exceeded in only 1.25 ms after the explosion, and the reversal bolt completely failed after 5.4 ms. Based on the result of the failed reversal bolt through the full-size experiment and M&S, the shape and size of the bolts were changed to re-design the M&S and re-analyze the sliding blast door. According to the M&S re-analysis result when the reversal bolt was designed in a square of 25 mm ($625mm^2$), the maximum pressure that the reversal bolt receives showed 81% of the principal tensile failure stress of the material, in plastic stage before fail.

• 대한방사선기술학회지:방사선기술과학
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• 제8권2호
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• pp.47-63
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• 1985

암수 흰쥐에 Cobalt-60 gamma선(線)을 200R, 400R, 600R, 800R, 1,000R, 1,200R, 1,300R. 1,400R, 1,500R, 1,600R 조사군(照射群)으로 나누어 1 일(日), 3 일(日), 5 일(日), 7 일(日)후에 나타나는 혈구(血球)의 수적(數的) 변화(變化)와 acid alkaline phosphatase (ACP ALP), lactic acid dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase(GPT)등의 효소(酵素) 활성(活性)의 변화(變化)를 측정(側定)한 결과 다음과 같은 결론(結論)을 얻었다. 1. 적혈구(赤血球) 수(數)의 변화(變化)는 200R 조사군(照射群)에서 암수 모두 3일군(日群)에서 최저치(最低値)를 나타내고 5일군(日群)과 7일군(日群)에 이르면서 증가(增加)하는 경향(傾向)을 보였으며, 백혈구(白血球) 수(數)의 변화(變化)는 모든 조사군(照射群)에서 1일군(日群) 이후(以後) 급격히 감소(減少)하는 경향을 나타내었다. 그리고 혈소판(血小板)의 수적(數的) 변화(變化)는 대체로 암수 모두 조사후(照射後) 1일(日)과 3일(日)에는 큰 변화(變化)를 보이지 않지만 5일(日) 이후에 급격한 감소현상을 보였다. 2. ACP의 활성도(活性度)는 암수모두 조사후(照射後) 3일(日)에서부터 점진적으로 감소(減少)하였고, ALP의 활성도(活性度)는 조사후(照射後) 5일(日)부터 감소(減少)하였다. LDH활성도(活性度)는 암수 모두 3일(日), 5일(日)부터 감소(減少)하였다. GOT활성도(活性度)는 암수 모두 1일(日)에는 증가현상을 나타내었다가 3일(日)에서부터 감소(減少)하였다. 그리고 GPT활성도(活性度)는 숫컷은 대조군(對照群)에 비(比)하여 큰 변동을 볼 수는 없었다. 암컷에서는 600R, 800R, 1,000R에서 3일(日) 이후 증가(增加)된 경향(傾向)이다. 3. 1,200R 이상의 고선량(高線量) 조사(照射)에서는 4일(日)후 전부(全部) 치사(致死)하였으며 1,600R 조사(照射)에서는 3일후(日後) 전부(全部) 치사(致死)하여 고선량(高線量)의 조사(照射)에는 민감한 생체(生體) 반응(反應)을 나타내었다.