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Huang Y, Li J. Discomfort estimation for vertical whole-body vibration in the aircraft cabin considering the duration and static sitting comfort. ERGONOMICS 2024; 67:327-338. [PMID: 37262307 DOI: 10.1080/00140139.2023.2221420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/20/2023] [Indexed: 06/03/2023]
Abstract
This paper investigated the discomfort caused by vertical whole-body vibration (WBV) over 20 minutes using data recorded at the front, middle, and rear seats of the passenger cabin in civil aviation during a cruising flight. Twenty-four subjects experienced each stimulus at 0.5 ms-2 r.m.s. and judged discomfort at various moments (i.e. 1/6, 5, 10, 15, and 20 min) using a category-ratio method. The difference in discomfort due to high-frequency vibration components vanished after 10 min. Based on Stevens' power law, a method is developed to estimate long-term vertical WBV discomfort by considering the static discomfort and an interaction coefficient between vibration and static discomfort as parameters. The proposed estimation method showed high accuracy with determination coefficients (R2) higher than 0.97 and good linearity with values of growth rates 0.95, 1, and 0.95 for the vertical WBV discomfort at the front, middle, and rear seat positions in the aircraft cabin.Practitioner summary: An estimation method for the discomfort caused by vertical WBV considering the duration and static sitting discomfort is developed. This method can provide accurate discomfort estimating for long-term vibration exposure, e.g. in civil aviation during a cruising flight, by introducing an 'interaction term' between static and dynamic discomfort.
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Affiliation(s)
- Yu Huang
- School of Mechanical Engineering, Institute of Vibration, Shock and Noise, Shanghai Jiao Tong University, Shanghai, China
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, China
| | - Jingdong Li
- School of Mechanical Engineering, Institute of Vibration, Shock and Noise, Shanghai Jiao Tong University, Shanghai, China
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Zhou J, Wu Z, Fan C, Yu T, Yi S, Li Y, Peng Y. Evaluation and prediction method of railway passenger long-term vibration comfort under complex operating conditions. ERGONOMICS 2023; 66:1999-2011. [PMID: 36734359 DOI: 10.1080/00140139.2023.2176552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Vibration contributes large increases in railway passenger discomfort during long-term sitting. Discomfort caused by vibration may differ in different operation conditions. This paper conducted field measurements to investigate the interrelationships between the three. Participants completed a 240-min train journey with their whole-body vibration, subjective comfort ratings and train operating parameters being recorded. A large correlation was observed between the estimated vibration dose value and subjective comfort. The relationship that vibration magnitude significantly increases with increasing the train speed and tunnel density was also found and quantified. A vibration exposure limit of 2.08 m/s1.75 corresponding to the boundary between subjective ratings of comfortable and discomfortable was obtained. Based on the exposure limit and the quantified relationship, a vibration comfort prediction method that can calculate the passenger's maximum tolerance time under a given operation condition was proposed and may help in determining the optimal operating speed and tunnels distribution to alleviate vibration discomfort. Practitioner summary: Similar to the guide to effect of vibration on health in current standard, a vibration exposure limit regarding comfort was provided for reference when assessing long-term vibration comfort. Meanwhile, a prediction method was proposed for determining the best train operating speed and tunnels distribution, thereby alleviating railway passengers' vibration discomfort.
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Affiliation(s)
- Jiahao Zhou
- Key Laboratory of Traffic Safety on Track of Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha, China
- Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha, China
| | - Zhifa Wu
- Key Laboratory of Traffic Safety on Track of Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha, China
- Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha, China
| | - Chaojie Fan
- Key Laboratory of Traffic Safety on Track of Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha, China
- Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha, China
| | - Tianjian Yu
- School of Traffic and Transportation Engineering, Central South University, Changsha, China
| | - Shengen Yi
- Research Laboratory of Hepatobiliary Diseases General Surgical Department, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yunchao Li
- The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yong Peng
- Key Laboratory of Traffic Safety on Track of Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha, China
- Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha, China
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Simões MRL, Assunção AÁ, Medeiros AMD. [Musculoskeletal pain among bus drivers and fare collectors in the Metropolitan Region of Belo Horizonte, Brazil]. CIENCIA & SAUDE COLETIVA 2018; 23:1363-1374. [PMID: 29768593 DOI: 10.1590/1413-81232018235.13542016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/24/2016] [Indexed: 11/22/2022] Open
Abstract
Musculoskeletal pain among professionals in the transport sector has been linked to working conditions. The scope of this study was to assess the prevalence of cervical musculoskeletal pain and its relation to pain in other areas (arms, hands and shoulders). The association between neck pain, related to pain in other areas or otherwise, was checked against occupational factors. A cross-sectional, descriptive and analytical study was conducted with 799 bus drivers and 708 fare collectors of the Metropolitan Region of Belo Horizonte, Brazil. The outcome was characterized according to the positive answer to the question about musculoskeletal pain in the anatomical areas studied. The prevalence of neck pain in the sample was highest at 16.3%, followed by pain in the shoulders 15.4%, arms 13.3% and hands 6.3%. The factors associated with musculoskeletal pain in the sample were being female, complaints of disability, perception of threat to safety, vibration, excessive or unbearable noise and sitting in an uncomfortable posture. The results provide clues to transformation of the workplace, thereby contributing to the enhancement of occupational health.
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Affiliation(s)
| | - Ada Ávila Assunção
- Faculdade de Medicina, Universidade Federal de Minas Gerais. Belo Horizonte MG Brasil
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Rodseth J, Washabaugh EP, Al Haddad A, Kartje P, Tate DG, Krishnan C. A novel low-cost solution for driving assessment in individuals with and without disabilities. APPLIED ERGONOMICS 2017; 65:335-344. [PMID: 28802454 PMCID: PMC5568672 DOI: 10.1016/j.apergo.2017.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/16/2017] [Accepted: 07/17/2017] [Indexed: 05/29/2023]
Abstract
Brake reaction time is a key component to studying driving performance and evaluating fitness to drive. Although commercial simulators can measure brake reaction time, their cost remains a major barrier to clinical access. Therefore, we developed open-source software written in C-sharp (C#) for measuring driving related reaction times, which includes a subject-controlled vehicle with straight-line dynamics and several testing scenarios. The software measures both simple and cognitive load based reaction times and can use any human interface device compliant steering wheel and pedals. Measures from the software were validated against a commercial simulator and tested for reproducibility. Further, experiments were performed using hand controls in both able-bodied and spinal cord injured patients to determine clinical feasibility for disabled populations. The software demonstrated high validity when measuring brake reaction times, showed excellent test-retest reliability, and was sensitive enough to determine significant brake reaction time differences between able-bodied and spinal cord injured subjects. These results indicate that the proposed simulator is a simple and feasible low-cost solution to perform brake reaction time tests and evaluate fitness to drive.
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Affiliation(s)
- Jakob Rodseth
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Edward P Washabaugh
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Ali Al Haddad
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Paula Kartje
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Denise G Tate
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Chandramouli Krishnan
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA; School of Kinesiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
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Mansfield N, Sammonds G, Nguyen L. Driver discomfort in vehicle seats - Effect of changing road conditions and seat foam composition. APPLIED ERGONOMICS 2015; 50:153-159. [PMID: 25959330 DOI: 10.1016/j.apergo.2015.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 03/03/2015] [Accepted: 03/10/2015] [Indexed: 06/04/2023]
Abstract
Discomfort in vehicle seats is a multi-factorial problem with contributions occurring from effects of sitting duration, seat design, and the dynamic environment to which the occupant is exposed. This paper reports laboratory studies investigating the extent to which reports of discomfort are affected by vibration commencing or ceasing, and whether methods of assessment are sensitive enough to detect small changes in foam composition. Study 1 measured discomfort ratings for two conditions of 60 min each, comprising 30 min of vibration exposure followed by 30 min of static sitting in a car seat, and vice-versa. Study 2 measured discomfort ratings for three conditions over a period of 40 min each, whilst participants were sitting in one of two car seat compositions, and either exposed to vibration or not. In both studies participants operated a driving simulator. It is shown that exposure to vibration increases the rate of discomfort onset in comparison to periods of static sitting. When vibration stopped, there was an acute improvement in comfort but discomfort did not drop to the levels reported by those who had been unexposed. When vibration started after 30 min of static sitting, there was an acute increase in discomfort but not to the levels reported by those who had been exposed to 30 min of vibration. After 40 min of continuous exposure it was possible to detect significant differences in overall discomfort between the two seat compositions, although trends could be observed in less time.
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Affiliation(s)
- Neil Mansfield
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, LE11 3TU, UK.
| | - George Sammonds
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, LE11 3TU, UK
| | - Linh Nguyen
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, LE11 3TU, UK
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