• 한국자동차공학회논문집
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• 제18권2호
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• pp.31-38
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• 2010

Bus manufacturers have tested and studied the dynamic collapse behavior of a bus body structure in rollover since UN ECE established ECE Regulation 66 to provide the requirement for the strength of bus structure. In spite of the costly cycles of practical tests, however, it is still a hard task to meet the rollover regulation by means of local reinforcements in the bus structure. Therefore it is necessary to develop a well designed strategy for the rollover strength implemented in the early stage of vehicle development. In this study, the suitable development method for each design stage from a component to complete body structure was considered to make a well-established development process of a bus body structure for rollover safety. For the efficient approach of the concept design stage, a numerical model based on the plastic hinge theory was used instead of detailed shell models. After setting up the concept design for the component size and geometry, the shell model was used to confirm and optimize the whole structure composition. The process developed in this study was practically used as an effective method to predict the rollover behavior of a new bus body structure.

• 한국자동차공학회논문집
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• 제11권2호
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• pp.126-133
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• 2003

The aerodynamic characteristics of automobiles have received substantial interest recently. Detailed knowledge of the vehicle aerodynamics is essential to improve fuel efficiency and enhance stability at high-speed cruising. In this study, a numerical simulation has been carried out for three-dimensional turbulent flows around a commercial bus body. Also, the effect of rear-spoiler attached at rear end of bus body was investigated. The Wavier-Stokes equation is solved with SIMPLE method in general curvilinear coordinates system. RNG $k-\varepsilon$ turbulence model with the MARS scheme was used for the evaluating aerodynamic forces, velocity and pressure distribution. The results showed details of the three-dimensional wake flow in the immediate rear of bus body and the effect of rear-spoiler on the wake structure. A maximum of 14% reduction in drag coefficient was achieved for a model with a rear-spoiler.

• 대한인간공학회지
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• 제36권2호
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• pp.69-86
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• 2017

Objective: The present study is intended to develop an improved bus seat armrest design by evaluating various bus armrest designs from ergonomic aspects. Background: An ergonomic armrest design which considers the sitting postures and body shapes of passengers can improve the convenience and comfort of a bus seat. Method: Subjective satisfaction of each of five design dimensions (length, width, height from seatpan, shape, and angle) was evaluated for seven bus seat armrest designs in various sizes and shapes by 58 participants (28 males and 33 females) using a 7-point scale (1: very dissatisfied, 4: neutral, and 7: very satisfied). Improved bus seat armrest designs adjustable in length and rotatable to the left or right (sliding and rotating armrest, SRA) with a concave, flat, or convex shape of the upper part were developed by considering the preferred design features and the body size and shape in sitting posture and needs of passengers and then compared with a conventional armrest. Results: A bus seat armrest with a wide width (40~50mm), a long length (360mm), a lower height (213mm), and a curved shape was found significantly preferred in terms of comfort. The proposed armrest designs (SRA-convex, SRA-flat, and SRA-concave) improved satisfaction by 46~62% for length suitability, 184~216% for width suitability, 205~214% for angle suitability, 138~181% for contact area suitability, and 49~64% for height suitability, 138~174% for comfort, and 93~111% for overall satisfaction. Conclusion: The preferred design features and passengers' needs of bus seat armrest were identified and the SRA designs were recommended for better usability. Application: The ergonomic design process of bus seat armrest employed in the present study can be applied to designing armrests in various vehicles for better convenience and comfort.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.28-35
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• 1997

Occupant injuries are always possible in a rollover accident, one of the major accidents in a bus. Thus the structure of body frame should have sufficient strength to protect passengers under accidental loads,. ECE(Economic Commission for Europe) regulation No.66 prescribes that residual space shall be preserved in the passenger compartment during and after the structure has been subjected to the prescribed rollover test. Rollover test on a bus section was completed according to the regulation. The coordinates of body section before and after rollover were measured, and it was checked that the structure still complied with the requirements of residual space. Direct measurement on a bus is difficult because of its large size. Thus photogrammetry by photographing and 3 dimensional digital modeling was introduced, and the coordinates of each point were measured through this method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.548-553
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• 2008

Low Floor buses have no steps to get on or get off the main cabin to provide the old and the handicapped with easy access. The car body for the low floor bus was designed to consider Korean physical standard, passenger capacity (standee, seated, handicapped), arrangement of vehicle components, and bus law or regulations. It was designed as an one body, without any reinforcement armature, which has light-weight sandwich constructions with glass epoxy skins, aluminum honeycomb cores and inner-frames. In this paper, torsion rigidity of the designed car body was evaluated and compared with that of a car body with reinforcement armatures in the cabin. Finite element method verified that the designed car body without reinforcement armatures could satisfy requirements of torsion rigidity.

• 한국공작기계학회논문집
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• 제13권1호
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• pp.88-93
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• 2004

In general, a fundamental structural design consideration for an automobile is the overall dynamic behavior in bending and torsion. Dynamic behavior of the automobile are mainly influenced by the structural stiffness of B.I.W.(body-in-white) and the physical property of trim components. In this paper, the modeling techniques for various trim components of middle-sized bus are presented, and the dynamic effects of the trim components on the vibration characteristics of the bus are investigated. The $1^{st}$ torsional frequency is decreased by attaching windshield and backlite to the B.I.W., but the $1^{st}$ vertical bending frequency and the $1^{st}$ lateral bending frequency are increased. The natural frequencies of the bus are decreased by attaching doors and windows. And also, the natural frequencies of the bus are large decreased by attaching seats, instrument panel etc. The study shows that the dynamic characteristics of the bus can be effectively predicted in the initial design stage.

• 한국직업건강간호학회지
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• 제7권2호
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• pp.130-135
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• 1998

To investigate the working characteristics of the workers by place of duty, a study was carried out among 591 male workers aged 20-55 employed in an automobile industry in Korea. Workers participated to this study were divided into low back pain(LBP) and control group, according to the self-reports by written questionnaires. Work factors and complaint rates of low back pain were compared to the work places. The results were as follows ; 1) The complaint rates of low back pain were 49.2%(292 men) as a whole, 58.6%(34 men) in Production Control Department I, 50.2%(120 men) in Stamping Tool Department, 46.9%(138 men) in Bus Department. 2) Lifting and earring work of individual workers were directly associated with low back pain. Frequency of lifting and carring work is higher in the Final Body Section(Production Dept. I) and Body I Section(Bus Dept.). 3) LBP group were more frequently involved in working in awkward position(Quality Control Section of Stamping Tool Dept.), bending(Body I Section of Bus Dept.) and twisting posture(Sash Section and Body I Section of Bus Dept.). 4 )Workers exposed to vibration during working shows the higher complaint rate of low back pain.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.1-6
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• 1998

A leaf spring plays an important role in a passenger bus. Since characteristic of a leaf spring has a hysteresis behaviour, modeling technique for a leaf spring is an important issue for passenger bus analysis. In this paper, modeling technique for a leaf spring is presented. First, non-linear FEM model of a leaf spring is constructed then it is used to make an approximated model to be used in dynamic analysis. The modeling procedure is ex-plained in step by step approach. Then, this model is applied to dynamic analysis of a mini-bus with flexible body and non-linear dynamic force element. The results are compared with test data.

• 제어로봇시스템학회논문지
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• 제16권6호
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• pp.524-531
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• 2010

The automobile networks consist of the communication bus systems which become independent and heterogeneous each other. Most often, the CAN buses are implemented in a car in order to connect all the electronic control units in various ways. Thus, some gateways are necessary for exchanging the useful information between electronic control units on the buses. The automobile body networks group is divided into two kinds on a large scale, namely the low-speed bus and the high-speed bus. To interchange messages between the two, a CAN signal gateway is designed and implemented in a miniature scale. A network analyzer (called "Vehicle spy") and an oscilloscope monitor network situation to confirm the due operation of CAN signal gateway. The efficiency of the designed gateway is evaluated. The more message thread increased, the more efficiency decreased.

• 대한인간공학회지
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• 제30권5호
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• pp.659-669
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• 2011

Objective: The aim of this study is to suggest a package layout guideline for low-floor bus by interview with passengers and observations of their behavior. Background: Increasing attention has been introduced the low-floor bus to be more suitable for use by transportation handicapped. Complex issues are involved in providing comfortable services to all people. We are going to suggest package layout guidelines for more comfortable and suitable travel to all people. Method: The two times of survey and video observation sessions were conducted on low-floor buses in Seoul; (1) a finding of potential issues in the first session, (2) a confirming of issues from the last session. Results: The three of major issues were founded in this study; (1) difficulties in supporting body when standing, (2) difficulties in sitting on front wheel pan seat, (3) difficulties in passing through the aisle. Conclusion: There were clear differences between public and transportation handicapped in using some tools which are used for support body such as roof hand rails, side hand rails, and hand rail rings. Some of design problems were founded to improve from the perspective of ergonomics and universal design. Such differences and design guidelines have to be considered in bus design as well as commercial vehicle. Application: The proposed design guidelines can be used to development of low-floor bus and other public transportations.