• Title/Summary/Keyword: 정차진동

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Equivalent Discomfort Curve on Idle Vibration Frequency of Passenger Vehicle (승용차량의 정차진동 주파수에 대한 불편함의 등감각곡선)

  • Jeon, Gyeoung-Jin;Lee, Jae-Young;Ahn, Se-Jin;Jeong, Weui-Bong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.6
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    • pp.535-541
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    • 2012
  • The three-down one-up method which is commonly used in the field of psychophysics is employed in this study that is to reveal how much magnitude of vibration makes discomfort in passenger vehicle on idle condition. Thirteen taxi drivers were invited for subject of the experiment where they evaluated the controlled vibrations on rigid seat in terms of idle vibration on passenger vehicle at frequency range from 15 Hz to 40 Hz. As the result, vibration of 100~105 dB is marginal range to make discomfort on passenger seat. Frequency dependency of the discomfort was found at the frequency range, which is the higher frequency the lower discomfort with the same magnitude of vibration. The frequency dependency found here was compared with ISO 2631-1 that is more sensitive at the frequency range.

The Study of Correlation between Objective Human Response and Subjective Discomfort Evaluation of Idle Vibration on Passenger Vehicle (승용차량 정차시 발생하는 진동에 대한 객관적 인체반응특성과 주관적 불편함평가의 상관성에 관한 연구)

  • Lee, Jae-Young;Jeon, Gyeoun-Jin;Ahn, Se-Jin;Jeong, Weui-Bong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.455-460
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    • 2012
  • Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.

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The Study of Correlation between Objective Human Response and Subjective Discomfort Evaluation of Idle Vibration on Passenger Vehicle (승용차량 정차시 발생하는 진동에 대한 객관적 인체반응특성과 주관적 불편함평가의 상관성에 관한 연구)

  • Lee, Jae-Young;Jeon, Gyeoung-Jin;Ahn, Se-Jin;Jeong, Weui-Bong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.5
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    • pp.422-428
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    • 2012
  • Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.

Evaluation of idle vibration beated by cooling fan imbalance (팬 작동에 따른 비팅성 아이들 진동 평가)

  • Park, Jinhan;Ahn, Sejin;Jeong, Weuibong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.247-249
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    • 2014
  • The beating phenomenon occurs because of various causes, when idle vibration was happened. In this study, the beating phenomenon was divided into several parameters and controlled by the parameter. It was hypothesized that the beating parameter is related to discomfort of idle vibration. The three-down one-up method was performed for evaluating discomfort of controlled vibrations, which is widely used in the field of psychophysics. As a result in pilot test, a subject responds beating vibration more discomfort than normal idle vibration. In the future, the study will be implemented to know how much the parameters of beating signal affect to the discomfort at idle vibration in passenger vehicle.

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Evaluation of Ride Comfort of the Passenger Vehicle Seat on idle vibration by Virtual Seat Method (Virtual Seat Method를 이용한 승용차량 시트의 정차시 진동에 대한 승차감 평가)

  • Lee, Jae-young;Ahn, Se-jin;Jeong, Wei-bong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.780-787
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    • 2013
  • Virtual Seat Method (VSM) is used in this study for a combined evaluation method (objective & subjective) to determine comfort value of passenger vehicle seat in terms of idle vibration. In the study, a process for applying VSM divided into two stages is established. Two kinds of seat mounting passenger vehicle and six subjects are employed to compare the comfort value obtained by VSM method and by SEAT value. As a conclusion, the results by the two methods were well consistent so that VSM is verified as a method to measure ride comfort of seat in terms of idle vibration at passenger vehicle.

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Human Response to Idle Vibration of Passenger Vehicle Related to Seating Posture (승용차량의 아이들 진동을 고려한 착석자세에 따른 인체의 반응특성 분석)

  • Jeon, Gyeoung-Jin;Kim, Min-Seok;Ahn, Se-Jin;Jeong, Weui-Bong;Yoo, Wan-Suk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.12
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    • pp.1121-1127
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    • 2010
  • Human characteristic responding to idle vibration on passenger vehicle was studied to find if affected by seating posture of passenger. When twelve male subjects are exposed to moderate vertical vibration of 0.224 $m/s^2$ r.m.s. at frequency range from 3 Hz to 40 Hz, it was found that seating posture significantly affects to biodynamical characteristics, apparent mass and apparent eccentric mass, at most range of idle vibration frequency(20~40 Hz). The supported thigh contact on rigid seat showed bigger values in the two biodynamical characteristics than the average thigh contact. The bigger apparent mass and apparent eccentric mass in the seating posture of the supported thigh contact can be assumed more strengthened muscle at the frequency range.

Evaluation of Ride Comfort of the Passenger Vehicle Seat on Idle Vibration by Virtual Seat Method (Virtual Seat Method를 이용한 승용차량 시트의 정차시 진동에 대한 승차감 평가)

  • Lee, Jae-Young;Ahn, Se-Jin;Jeong, Wei-Bong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.7
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    • pp.631-639
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    • 2013
  • Virtual seat method(VSM) which is an evaluation method combined objective and subjective process is used in this study in order to determine seat comfort index of idle vibration of passenger vehicle. The VSM is implemented by two steps which are for objective index in the first step and for subjective estimation in the second step. In the study, two seats mounted on passenger vehicle was compared in terms of dynamic seat comfort by six subjects employed for the VSM method as well as SEAT value which is a conventional objective method. It is concluded that the dynamic comfort index by the VSM is more reliable than the SEAT value thanks to adding subjective evaluation on top of the objective result.

Study of Apparent Mass and Apparent Eccentric Mass to Vertical Whole-body Vibration by Using Strain-gage Type Six-axis Force Plate (6축 힘측정판을 이용한 수직방향 전신진동에 대한 겉보기질량 및 겉보기편심질량에 대한 고찰)

  • Jeon, Gyeoung-Jin;Kim, Min-Seok;Ahn, Se-Jin;Jeong, Weui-Bong;Yoo, Wan-Suk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.10
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    • pp.897-904
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    • 2011
  • When whole-body is exposed to vertical vibration, asymmetry shape of human body affects the response on the translational(fore-aft, lateral, vertical) and rotational(roll, pitch, yaw) motion. While the translational motion has been studied with various titles, it has been rare to study the rotational motion of human body exposed to vertical excitation because of lack of experimental equipment. This study was performed by using a 6-axis force plate installing strain gage type sensors for the rotational response. Sixteen male subjects were exposed to vertical vibration on rigid seat in order to investigate apparent mass of three translational motion and apparent eccentric mass of three rotational motion. Random signal was generated to make excitation vibration which was on an effective frequency range of 3~40 Hz, and magnitude of 0.224 m/$s^2$ r.m.s. The frequency range and magnitude used was selected for the vibration of passenger vehicle on idling condition. As the result, cross-axis apparent masses of fore-and-aft and lateral direction were not significant showing 20 % and 3 % of vertical apparent mass relatively. And apparent eccentric mass of pitch motion was dominant when compared to that of roll and yaw motion, which is reasoned by asymmetry direction of human body sitting on a seat.

Analysis of Unstable Vibration Modes due to KTX Brake Disc/Pad Interaction (KTX 제동디스크-패드의 상호작용에 의한 불안정 진동모드 해석)

  • Goo, Byeong Choon
    • Journal of the Korean Society for Railway
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    • v.16 no.4
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    • pp.253-261
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    • 2013
  • According to the measured results of KTX brake squeal noise in this study, high level brake noise occurred in a wide frequency range, 100~18,000Hz. To identify the sources of the brake squeal noise, unstable vibration modes due to brake disc/pad interaction were analyzed under various conditions by the finite element method. Complex eigenvalues for a brake unit with a disc and four pads were obtained. It was found that the real parts of the complex eigenvalues, that is, unstable vibration modes, were closely related to friction coefficients, pressure on the brake cylinders, elastic moduli of the components, and other conditions.