• Title/Summary/Keyword: Contact patch

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Vehicle Vibration Study by Tire Flat Spot (타이어 플랫 스팟에 의한 차량진동 연구)

  • Park, Ju-Pyo;Choi, Jung-Hyun;Lee, Sang-Ju
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1395-1400
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    • 2007
  • Tire flat spot is a deformation which occurs around the contact patch during long-period parking and does hardly recovered even after driving. The deformation makes a tire self-excited and ride comfort gets worse. In this study, it is shown that the flat spot can be evaluated by measuring change in radial run out or force. Its effects on vibration at vehicle floor and steering wheel are also revealed. Finally it is shown that the flat spot is likely to occur if the inflation pressure is low and the tire is suppressed by a heavy load at a high temperature.

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A Study on Measurement of Heartrate and Respiration during Sleep using Doppler Radar: Preliminary Study (도플러 레이더를 이용한 수면 중의 심박 및 호흡 측정: 예비연구)

  • Lim, Yong Gyu
    • Journal of Biomedical Engineering Research
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    • v.38 no.5
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    • pp.264-270
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    • 2017
  • A Doppler radar sensor was applied to detect respirations and heartbeats of persons who were lying on a bed. This study is preliminary study aiming at non-contact and non-intrusive respiration and heart rate monitoring during sleep in daily life. For the experiments, 10GHz Doppler radar with patch-type antenna was used and installed on the upper right and the distance between the body and the antenna was 1 m. The results show that each signal of respiration and heartbeat is observed in each frequency band however the frequency band and the waveform vary according to the subjects and the posture. The results show that the heartbeats can be detected with the peak detection in some frequency band. This study shows the feasibility of applying the Doppler radar to detection of heartbeat and respiration during sleep and further studies about heartbeat detection algorithm are required.

The Study on the Characteristics of Groove Wandering and Noise Caused by the Design Parameter of Longitudinal Groove on the Tire's Pattern (타이어 패턴의 종그루브 인자에 따른 그루브 원더링 및 소음 특성 연구)

  • Han, Jin-Hyuk;Hwang, Sung-Wook;Kang, Yong-Gu;Han, Min-Hyeon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.5
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    • pp.110-116
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    • 2011
  • Water on a road surface can lower the coefficient of friction of vehicle tires and it involves lots of risks. One way to prevent water from staying is to cut many "rain grooves" into the edges of the pavement parallel. Such grooves, however, can exert unwanted side forces, particularly on passenger tires, which cause "Groove Wander" making the drivers uncomfortable. The "Groove Wander" is somewhat related to vehicle geometry, but is more strongly related to interaction between road grooves and tire tread's longitudinal grooves. This thesis tries to examine principles to estimate "Groove Wandering" effect focusing on the design of longitudinal groove. Additionally, it studied how to reduce pipe resonance longitudinal grooves form in the contact patch.

Analysis about the new wheel changes of the rolling stocks after using the loop in Seoul Metro 2.3 lines (서울 메트로 2.3호선 루프선 사용 전후의 전동차 차륜교환분석)

  • Kim, Dong-Min;Ahn, Jong-Kon
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.35-50
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    • 2007
  • A contact patch between the wheel and the rail supports the train body and a traction power comes from it when rolling stocks run on the railroad. Friction force between the wheel and rail makes the train move on the rail. Whenever the train runs on the rail, the wheels and rails wear down by frictions inevitably. So it must be shaped by the lathe or changed for the safety train operation and the comfortable ride. Until now, many measures were carried out in order to prevent a wear and tear of the wheels. For example loop line railway in Kun Ja depot and Ji Chuk depot. This document reports the wheel changing data taken by maintenances department for the period before and after 1996 in the 1.2.3.4 lines in Seoul metro.

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Four Homalotine Species New to Korea (Coleoptera: Staphylinidae: Aleocharinae)

  • Kim, Yoon-Ho;Ahn, Kee-Jeong
    • Animal Systematics, Evolution and Diversity
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    • v.30 no.3
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    • pp.191-195
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    • 2014
  • Four homalotine species-Anomognathus armatus (Sharp), Heterota onorum Maruyama, Neosilusa ceylonica (Kraatz), and Silusa lanuginosa Sharp-and three genera-Anomognathus Solier, Neosilusa Cameron, Silusa Erichson-are identified for the first time in Korea. The tribe Homalotini can be distinguished from other related tribes by the combination of the following characters: tarsal formula 4-4-5; mandible with patch or rows of denticles in ventral molar region; base of medial setae of prementum very close together, setal insertions in contact in many, setae displaced one behind the other in some; medial pseudopore field of prementum very narrow in many. Habitus photographs, diagnoses, and illustrations of male genitalia of these four species are provided.

PREDICTION OF SOUND RADIATION FROM TIRE TREADBAND VIBRATION

  • Kim, B.S.
    • International Journal of Automotive Technology
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    • v.2 no.1
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    • pp.33-38
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    • 2001
  • The noise generated from a treadband mechanism of a tire has been the subject of this research. In particular, the treadband has been treated as an infinite tensioned beam resting on an elastic foundation which includes damping. The main objective is here to predict the sound power generated from a system mentioned above by locating harmonic point forces representing the excitation of treadband at the contact patch. It is possible to predict the sound power radiated from this structure by wavenumber transformation techniques. To find out the minimum radiated sound power, All parameters were varied. Thus this model can be used as a tire design guide for selecting parameters which produce the minimum noise radiation.

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A Study on the Establishment of Management Methods about Occupational Dermatoses (직업성 피부질환에 대한 현황 파악 및 관리 대책 수립을 위한 연구)

  • Lim, Hyun-Sul;Cheong, Hae-Kwan;Choi, Byung-Soon;Kim, Ji-Yong;Sung, Yeol-Oh;Kim, Yang-Ho
    • Journal of Preventive Medicine and Public Health
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    • v.29 no.3 s.54
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    • pp.617-637
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    • 1996
  • Occupational dermatosis is one of the most prevalent occupational disorders. However, the extent of the occupational dermatoses including incidences and prevalencies of each disease entity, and etiologic materials are not yet welt stated in Korea. Authors reviewed the literatures on the statistic data and reports on the occupational dermatoses, and surveyed on the occupational dermatoses in two factories, and surveyed the physicians responsible to the occupational dermatoses with formed questionnaire. The results are as follows; 1. Among medical journals published since 1964, there were 31 articles on the occupational dermatoses. Of 31 articles, 18 were case reports and all others were review articles. Of 18 case reports, 9 were epidemiologic survey. The Workers' Periodic Health Examinations revealed that prevalence of the occupational dermatoses was highest(4.36 per 10,000 workers) in 1974, but number of the cases reported were decreased sharply since 1978 with some tendency to increase since 1981. There were 2,240 reported cases of occupational dermatoses between 1966 and 1992, which is 1.90% of all the reported occupational diseases. Skin infection and injuries due to chemicals were most frequent and there were 6 cases of skin cancer. 2. In an epidemiological survey on the dermatoses among 995 workers in a metal product manufacturing factory and 225 workers in a coal chemical factory, there were 794 with dermatomycosis, 296 workers with acne, 130 workers with scar, 123 workers with deformity of toe nails. Scars, photosensitivity dermatitis, deformity of finger and toe nails, and acne were more prevalent in the metal product manufacturing factory(p<0.05). In the metal prouct manufacturing factory, workers treating organic solvents and oils had more dermatoses than those without treating the materials(p<0.05). On the skin patch performed on 16 workers in the metal product manufacturing factory, there were 8 cases of irritation dermatitis and 5 cases of contact dermatitis. Prevalence of contact dermatitis in the metal product manufacturing factory was 1.3%. 3. On the questionnaire survey, 34 dermatologists, 29 doctors of preventive medicine, and 22 family physician replied. The proportion of occupational etiology among all dermatoses assumed by the physicians were below 9%, and the most important occupational dermatosis in Korea was contact dermatitis. Main etiologic materials related to the occupational dermatosis were organic solvent, acid and alkali, and metals. The reason for the scarcity of report of occupational dermatoses were difficulty in diagnosis and physician's ignorance of the occupational etiology. They replied that to prevent the occupational dermatoses in the workplace, the use of protective devices was most important, and development of diagnostic criteria on the occupational dermatoses is urgent. Above results shows us that there is many workers with occupational dermatoses, but they are mostly unreported. Measures to prevent and manage the occupational dermatoses are not satisfactory at present. Hence, authors suggest measures for the precise diagnosis, report and prevention of the occupational dermatoses. a. Dermatologist, preventive physician, and industrial hygienist should work as a team to examine the high risk group and establish the preventive measures. b. Disease entities, diagnostic criteria of occupational dermatoses should be listed, criteria for the compensation and job fitting at recruitment should be established, and manual for the proper treatment and effective prevention of each occupational dermatosis should be developed. c. Patch test antigens against each occupational category should be developed and it should be available to any physicians responsible. d. To facilitate the diagnosis of occupational dermatoses by the doctors responsible for the Workersr Periodic Health Examination, development of standardized questionnaire, education on the techniques of the patch test, and cooperation with the dermatologist in diagnosis of occupational dermatoses is essential.

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A Study on the tire structure-borne sound (타이어 구조 진동음에 관한 연구)

  • Chi, Chang-Heon
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.2
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    • pp.80-91
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    • 1995
  • A theoretical models has been prepared which describes the noise generated by tire/road interaction for the tire structure-borne sound analysis. The model begin with a set of thin shell equations describing the motion of the belt of a radial ply tire, as drived by Bohm('mechanisms of the belted tire', Igeniur-Archiv, XXXV, 1966). Structural quantities required for these equations are derived from material properties of the tire. The rolling shape of a tire is computed from the steady-state limit of these equations. Vibrational response of the tire is treated by the full dependent shell equations. The force input at the tire/road interface is calculated on the basis of tread geometry and distribution of contact patch pressure. Radiation of noise is calculated by a simpson integral. Using the programs, the effect on noise of various tire design variations is computed and discussed. Trends which lead to quiet tire design are identified.

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A General Description of Tool Surface Based on Finite Element Mesh and Its Application to 3-D Sheet Forming Processes (유한요소격자에 기초한 일반적인 금형면 묘사와 3차원 박판성형공정에의 응용)

  • Yun, Jeong-Hwan;Kim, Jong-Bong;Yang, Dong-Yeol;Kim, Seok-Gwan;Yu, Dong-Jin;Lee, Jae-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.550-559
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    • 2000
  • One of the most important factor to be considered for the analysis of sheet metal forming processes is the tool surface description for arbitrarily- shaped sheet metal parts. In the present study , finite element approach is used to describe the arbitrarily shaped tool surface. In finite element mesh approach, tool surfaces ar, described by finite elements. The finite elements mesh description of the tool surface, which is originally described by CAD data, needs much time and time-consuming graphic operation. The method, however, has been widely used to describe a complex tool surface. In the present study, the contact searching algorithm for the finite element mesh approach is developed based on cell strategy method and sheet surface normal scheme. For the verification purpose, a clover cup drawing, Baden-Baden oilpan problem and a trunk floor drawing were investigated. The computational results based on the finite element approach were compared with the results of available parametric patch approach and experiments.

Modeling of Debonding Detection Using Microstrip Patch Antenna (마이크로스트립 패치 안테나를 이용한 박리 탐사 모델링)

  • Rhim Hong-Chul;Lee Hyo-Seok;Woo Sang-Kyun;Song Young-Chul
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.35-39
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    • 2006
  • With a growing concern about the state of infrastructure worldwide, the demand for the development of reliable nondestructive testing techniques (NDT) is ever increasing. Among possible NDT techniques. microwave method is proven to be effective in fast and non-contact inspection of concrete structures and inclusions inside concrete. It is also found that the microwave method has a potential in detecting the delamination between fiber reinforced polymer (FRP) plate and concrete. On the other hand, ultrasonic method can be another way to find the delamination. In this paper, the research work needed for the development of a reliable microwave method and ultrasonic method is studied in actual measurements of concrete specimens reinforced with FRP. Concrete specimens are made with FRP and artificial delamination inside. A microwave measurement system with horn antennas with high center frequency and broad frequency bandwidth are used to image inside concrete specimens for the detection of debonding. between concrete and FRP. Also, the equipment of ultrasonic method which is commercialized are used at the same condition. Both of the results are analyzed in comparison of each other. Microwave and ultrasonic methods have been used for the detection of debonding between concrete and fiber-reinforced plastic (FRP).

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