• 한국기계가공학회지
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• 제21권4호
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• pp.14-22
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• 2022

To reduce the weight of the car and ensure the safety of the driver while driving, the existing 440 MPa-class mounting bracket was treated at 590MPa to improve collision safety and secure the weight of the vehicle body. The following conclusions were drawn from the tensile test, forming analysis, and springback prediction. In the formability and springback analyses using FLD, it could be confirmed that bending was an essential process because the formability and flatness were much better when bending was added than when bending was not applied. Based on the research results, it was deduced that the mold design was necessary so that the molding was carried out at a strain rate of 20% or less for stable molding.

• 산업경영시스템학회지
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• 제41권4호
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• pp.213-219
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• 2018

Mechanical components are to be produced with accurate dimensions in order to function properly in assemblies of a machine. Once designs of mechanical components are created, designers examine the designs by adopting many known experimental methods. A primary test method includes stress and strain evaluation of structural parts. In addition, fatigue test and vibration analysis are an important test method for mechanical components. Real experiments at a laboratory are established when products are manufactured. Since design changes should be done before producing the designs in factories, rapid modifications for new designs are required in production industries. FEM simulation is a proper choice for a design evaluation with speed at a detail stage in design process. This research focuses modeling and mechanical simulation of a mechanical component in order to ensure structural safety. In this paper, a universal joint, being used in driving axels of vehicles, is studied as a target component. A design model is created and tested in some ways by using commercial software of FEM. The designed component is being twisted to transmit heavy power and thus, torsional stress should be under strengths of the component's material. The next is fatigue analysis to convince fatigue cycles to be within the endurance limit of the material. Another test is a vibration analysis for rotational components. This research draws final conclusions from these test analyses and recommends whether the designed model is under safety condition in terms of mechanical structure.

• Safety and Health at Work
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• 제14권3호
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• pp.340-346
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• 2023

Background: Truck driving is a highly sedentary occupation that places workers at risk for chronic health conditions, such as obesity and high blood pressure. The primary purpose of this study was to objectively describe truck drivers' typical physical activity (PA) patterns. Methods: We used ~7-10-day baseline PA actigraphy data samples from drivers in the Safety & Health Involvement For Truckers (SHIFT) study (n = 394). Driver PA patterns (e.g., average number of ≥10 minute Freedson bouts per week, time in bouts, and common days/times for PA) were summarized with descriptive analyses. We also compared objective accelerometer data to self-reports. Results: Drivers' weekly PA averaged 14.4 minutes (SD = 37.0), and most PA occurred between 5-6 pm on Tuesdays and Wednesdays. Drivers overestimated self-reported weekly exercise by over 60 min/week compared to accelerometer data. Conclusion: Our results suggest that objective PA assessment may be warranted over self-report when possible, and timing may be key in future PA intervention work with truck drivers.

• 자동차안전학회지
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• 제14권4호
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• pp.27-34
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• 2022

In the development of automated driving, interest in the interior parts of vehicle is to become more significant in terms of the occupant safety and comfort. This study proposed an optimal design of front seat according to the design requirements for frame stiffness and seat comfort. For the seat comfort, the appropriate foam thickness was obtained using the structural analysis under reclined occupant loadings. While the strength and stiffness analyses were performed to evaluate the seat frame structure. Topology optimization was carried out based on the simulation results and the derived optimal model and baseline seat design was updated. The conceptual seat design for the autonomous vehicle in this study showed that the model development process is appropriate for the design parameters in both frame stiffness and seat comfort.

• 대한교통학회지
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• 제27권5호
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• pp.63-74
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• 2009

본 연구에서는 실시간 주행환경에서 전방의 위험상황에 대해 운전자가 효과적으로 반응 할 수 있는 교통안전 경고정보 컨텐츠 도출을 위한 연구를 수행하였다. 차내 단말기를 통해 제공되는 경고정보 유형에 따른 운전자 반응특성을 분석하였다. 운전자 반응특성자료를 수집하기 위하여 DGPS를 장착한 실험차량을 이용하여 개별차량 주행궤적을 수집하여 속도 및 가감속도를 산출하였다. 차내 경고정보 유형은 사고위험성과 직접적인 연관이 있는 긴급영향권과 긴급영향권에 진입하는 차량에게 위험발생의 사전정보를 제공하기 위한 일반영향권으로 분류하였다. 컨텐츠는 시각적 정보인 Text, 이미지와 청각적 정보인 경고음, 그리고 음성 메시지를 고려하여 다양한 시나리오를 제작하여 현장실험에 활용하였다. 분석 결과 긴급영향권에서는 음성+이미지+text와 경고음+text로 구성된 경고정보를 제공하는 것이 가장 효과적인 것으로 분석되었으며, 일반영향권에서는 경고음+음성+이미지+text로 구성된 경고정보를 제공하는 것이 가장 효과적인 것으로 나타났다. 본 연구 결과는 향후 운전자의 반응특성을 고려한 보다 효과적인 실시간 경고정보를 설계하기 위한 유용한 정보로 활용 될 것으로 기대된다.

• 한국정밀공학회지
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• 제33권9호
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• pp.761-768
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• 2016

Weight bearing is effective during rehabilitation of gait, in the elderly and disabled people. Various training devices using weight bearing function were developed along with treadmill walking; however, no device has been developed in conjunction to walking on the ground. Here, we designed a rail type frame of a gait rehabilitation system for body-weight support (BWS) function, and analyzed its mechanical safety in the static weight bearing condition of a vertical axis. Computational simulations were performed to analyze structure of the driving parts, which are connected with a rail and driving rollers and the lower plate of the BWS. Structural analyses showed the drivers and BWS were safe, when simulated at 135kg weight under static conditions. Thus, this rail type rehabilitation system can be used for gait training of the elderly and disabled.

• 대한산업공학회지
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• 제26권4호
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• pp.354-362
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• 2000

Increasing amount of road tragic in 90's has drawn much attention in Korea due to its influence on safety problems. Various types of data analyses are done in order to analyze the relationship between the severity of road traffic accident and driving conditions based on traffic accident records. Accurate results of such accident data analysis can provide crucial information for road accident prevention policy. In this paper, we apply several data fusion, ensemble and clustering algorithms in an effort to increase the accuracy of individual classifiers for the accident severity. An empirical study results indicated that clustering works best for road traffic accident classification in Korea.

• 대한교통학회지
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• 제29권3호
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• pp.103-114
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• 2011

본 연구는 2000년 이후 대형교통사고 발생지점 112건의 자료를 이용, 다양한 교차 및 빈도분석을 통해 대형교통사고와 도로 기하구조의 관계를 규명하고, 이를 토대로 대형교통사고 심각도 모형을 구축하였으며, 주행안전성 향상을 위해 720회의 컴퓨터 모의실험으로 다음과 같은 결론을 얻을 수 있었다. 첫째, 교차 및 빈도분석의 결과 커브구간에서 43.7%, 종단경사 기타조건에서 60.7%, 곡선반경 0~24m 구간에서 57.2%, 편경사 0.1~2.0% 구간에서 83.9%, 편도2차로 도로에서 49.1%, 차종별로는 승용(33.0%), 화물(20.5%), 버스(14.3%) 순이었으며, 편경사 설치 유 무가 대형교통사고 발생에 가장 큰 영향을 주는 것으로 분석되었다. 둘째, 순서형 프로빗 모형(Ordered Probit Model)을 이용하여 다양한 도로조건에서의 피해 예측이 가능한 대형교통사고 심각도 모형을 개발하였으며, 개발된 모형을 기반으로 도로의 위험성을 사전에 예측하고, 대책 마련이 가능토록 기여 하였다. 셋째, 컴퓨터 모의실험(Simulation) 결과, 이미 대형교통사고가 발생한 장소에 편경사를 설치했을 경우 약 85% 이상의 지점들에서 대형교통사고가 발생하지 않는 개선효과가 있는 것으로 분석되었으며, 이 분석결과를 통해 도로의 구조 시설 기준에 관한 규칙(해설 및 지침)의 편경사 설치 예외규정을 더욱더 강화시킬 필요가 있다고 사료된다.

• 대한안전경영과학회지
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• 제14권4호
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• pp.93-105
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• 2012

The purpose of this study was to investigate drivers' postures in different car pedal systems and skilled levels under fatigue. Twenty four subjects participated in this experiment. For three-dimensional analyses, six cameras (Proreflex MCU-240, Qualisys) were used to acquire raw data. The parameters were calculated and analyzed with Visual-3D. In conclusion, ROAs of two leg-pedal system were less than one leg pedal system by pattern analysis. Through statistical tests, skilled levels have effects on ROAs(X, Y, Z) of ankle joint at breaking a pedal and ROAs(Y, Z) of ankle joint at accelerating a pedal. Also, car pedal systems have effects on ROAs(Y, Z) of ankle joint, and ROA(Z) of knee joint at accelerating a pedal. In addition, skilled levels and car pedal systems (cross effects) have an effect on ROA(Z) of ankle joint. These findings suggested that we should improve a present single pedal system.

• 한국융합학회논문지
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• 제9권8호
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• pp.155-160
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• 2018

자동차 시트는 주행시 운전자의 편의와 안전을 제공하는 하나의 부품이다. 최근 그 시트는 의자와 같은 용도 외에 외부의 충격이나 진동으로부터 운전자를 보호하고 편의를 주는 역할을 하고 있다. 자동차의 충돌 안전성 및 내구성과 같이 시트 프레임의 구조적인 기능에 대한 설계가 중요하다. 본 연구에서는 시트 프레임의 구조적인 안전성과 내구성을 높이기 위하여 시트 백 프레임 부분에 환봉을 1개씩 증가하여 시트를 설계하였다. 설계 및 해석 프로그램으로는 CATIA와 ANSYS를 사용하여 본 연구를 수행하였다. 구조해석과 진동해석을 통한 본 연구 결과로서는 Model 4가 타 모델 대비 더 뛰어난 내구성을 가지는 것을 알 수 있었다. 이 결과를 이용함으로서 구조적인 안전성과 내구성을 가진 자동차 시트 프레임 설계를 할 때에 유용한 자료가 될 것이라고 사료되며, 자동차 시트 프레임의 디자인을 융합기술에 접목하여 미적 감각을 나타낼 수 있다.