Whole-Body Vibration in Locomotive Cabs

2011 ◽  
Author(s):  
Amanda M. DiFiore ◽  
Abdullatif K. Zaouk ◽  
Neil J. Mansfield ◽  
S. K. John Punwani
Keyword(s):  
Whole Body Vibration ◽  
Whole Body ◽  
Ride Quality ◽  
Shock Duration ◽  
Mechanical Shock ◽  
Body Vibration ◽  
Rail Vehicles ◽  
Mechanical Shocks ◽  
Iso 2631 ◽  
The Impact

Locomotives produce vibrations and mechanical shocks from irregularities in the track, structural dynamics, the engines, the trucks, and train slack movement (Mansfield, 2005). The different directions of the irregularities give rise to car-body vibrations in multiple axes including the following: • Longitudinal, or along the length of the train (x); • Lateral, or the side-to-side direction of the train (y); • Vertical (z). Some reports suggest that acceleration at the seat pan is greater than that at the floor, indicating that the seat may amplify the vibration (Johanning, et al., 2006; Mansfield, 2005; Oborne & Clarke, 1974; Transport, 1980). The magnitude of vertical vibration in rail vehicles is reportedly well below many other types of vehicles (Dupuis & Zerlett, 1986; Griffin, 1990; Johanning, 1998). However, some research reports that rail vehicles experience far more lateral vibratory motion than cars and trucks (Lundstrom & Lindberg, 1983). Many factors influence the impact of shock felt by the engineer including train speed, consist, engineer control skills, anticipation of the shock, motion amplitude, shock duration, and body posture. Shock events and vibration affect ride quality; however, shocks are less controllable by locomotive design. Common sources of mechanical shock are coupling and slack run-ins and run-outs (Multer, et al., 1998). While there are investigations of whole-body vibration (WBV) in locomotive cabs reported in the literature, there have been no studies to date that have examined long-haul continuous vibrations (> 16 hr). The authors describe a long-haul WBV study collected on a 2007 GE ES44DC locomotive. It is the first in a series of studies sponsored by the Federal Railroad Administration (FRA) to examine WBV and shock in locomotive cabs. The researchers recorded vibration data using 2 triaxial accelerometers on the engineers’ seat: a seat pad accelerometer placed on the seat cushion and a frame accelerometer attached to the seat frame at the base. Data collection occurred over 550 track miles for 16hr 44min. ISO 2631-1 defines methods for the measurement of periodic, random and transient WBV. The focus of ISO 2631-5 is to evaluate the exposure of a seated person to multiple mechanical shocks from seat pad measurements. The research team collected and analyzed vibrations in accordance with ISO 2631-1 and ISO 2631-5. The results from the study as well as future planned long-haul studies will provide a benchmark set of WBV metrics that define the vibration environment of present-day locomotive operations.

Long-Haul Whole-Body Vibration Assessment of Locomotive Cabs

2012 ◽  
Author(s):  
Amanda DiFiore ◽  
Abdullatif Zaouk ◽  
Samiullah Durrani ◽  
Neil Mansfield ◽  
John Punwani
Keyword(s):  
Structural Dynamics ◽  
Whole Body Vibration ◽  
Occupational Risk ◽  
International Standards ◽  
Whole Body ◽  
Ride Quality ◽  
Body Vibration ◽  
Rail Vehicles ◽  
Mechanical Shocks ◽  
Iso 2631

Locomotives produce vibrations and mechanical shocks from irregularities in the track, structural dynamics, the engines, the trucks, and train slack movement (Mansfield, 2005). The different directions of the irregularities give rise to car-body vibrations in multiple axes including the following: • longitudinal, or along the length of the train (x); • lateral, or the side-to-side direction of the train (y); • vertical (z). The structural dynamics of rail vehicles give rise to several resonances in the 0.5–20Hz frequency range (Andersson, et al., 2005). Resonances are frequencies in the locomotive that cause larger amplitude oscillations. At these frequencies, even small-amplitude input vibration can produce large output oscillations. Further exacerbating the vibration environment, coupling of the axes of movement occurs: Motions in one direction contribute to motion in a different direction. The magnitude of vertical vibration in rail vehicles is reportedly well below many other types of vehicles (Dupuis & Zerlett, 1986; Griffin, 1990; Johanning, 1998). However, a lack of data from long-haul freight operations prevents an adequate characterization of the vibration environment of locomotive cabs. The authors describe results from 2 long-haul whole-body vibration (WBV) studies collected on a 2009 GE ES44C4 locomotive and a 2008 EMD SD70ACe. These WBV studies sponsored by the Federal Railroad Administration (FRA) examined WBV and shock in locomotives over 123 hours and 2274 track miles. The researchers recorded vibration data using 2 triaxial accelerometers on the engineers’ seat: a seat pad accelerometer placed on the seat cushion and a frame accelerometer attached to the seat frame at the base. The research team collected and analyzed vibrations in accordance with ISO 2631-1 and ISO 2631-5. ISO 2631-1 defines methods for the measurement of periodic, random and transient WBV. The focus of ISO 2631-5 is to evaluate the exposure of a seated person to multiple mechanical shocks from seat pad measurements. Exposure to excessive vibration is associated with an increased occupational risk of fatigue-related musculoskeletal injury and disruption of the vestibular system. While this is not an established causal relationship, it is possible that vibration approaching the ISO 2631-1 health caution guidance zones may lead to an increased occupational risk. The results from these rides show that the frequency-weighted ISO 2631 metrics are below the established health guidance caution zones of the WBV ISO 2631 standards. The goals of these studies are to: • collect data in accordance with international standards so results can be compared with similar findings in the literature for shorter duration rides as well as vibration studies in other transportation modes, • to characterize vibration and shock in a representative sample of locomotive operations to be able to generalize the results across the industry, and • collect benchmark data for future locomotive cab ride-quality standards.

scholarly journals Occupational Vibration in Urban Bus and Influence on Driver’s Lower Limbs

2018 ◽  
Vol 4 (1) ◽  
pp. 56-66
Author(s):  
M. Cvetkovic ◽  
J. Santos Baptista ◽  
M. A. Pires Vaz
Keyword(s):  
Whole Body Vibration ◽  
Working Environment ◽  
Lower Limbs ◽  
Whole Body ◽  
Body Vibration ◽  
Prisma Statement ◽  
Physical Changes ◽  
Iso 2631 ◽  
The Impact ◽  
Whole Body Vibrations

The whole-body vibration occurs in many occupational activities, promoting discomfort in the working environment and inducing a variety of psycho – physical changes where consequences as a permanent dysfunction of certain parts of the organism may occur. The main goal of this short systematic review is finding the articles with the most reliable results relating whole-body vibrations to buses and, to compare them with the results of drivers’ lower limbs musculoskeletal disease which occurs as a consequence of many year exposure. PRISMA Statement Methodology was used and thereby 27 Scientific Journals and 25 Index - Database were searched through where 3996 works were found, of which 24 were included in this paper. As a leading standard for analysis of the whole-body vibration the ISO 2631 – 1 is used, while in some papers as an additional standard the ISO 2631-5 is also used for the sake of better understanding the vibrations. Furthermore, the European Directive 2002/44 / EC is included where a daily action exposure to the whole-body vibrations is exactly deter-mined. All the results presented in the paper were compared with the aforesaid standards. After having searched the databases, papers that deal with research of the impact of the vibration on the driver’s lower limbs did not contain any information’s on the described problem.

Development of a multiaxis active seat mount to mitigate helicopter aircrew whole-body vibration exposure

2019 ◽  
Vol 30 (17) ◽  
pp. 2544-2555
Author(s):  
Yong Chen ◽  
Shao Zhang ◽  
Jiaxin Chang ◽  
Amin Fereidooni ◽  
Viresh Wickramasinghe
Keyword(s):  
Health Effect ◽  
Whole Body Vibration ◽  
Whole Body ◽  
Ride Quality ◽  
Vibration Exposure ◽  
Least Mean Square ◽  
Body Vibration ◽  
Floor Vibration ◽  
Seat Frame ◽  
The Impact

This article presents the development and evaluation of a proof-of-concept multiaxis and actively controlled helicopter seat mount for aircrew whole-body vibration reduction. The multiaxis seat mount is designed to be installed between the helicopter seat floor and the seat supporting structure to minimize the impact on crashworthiness requirements of the helicopter seat. The design involves multiple miniature force actuators to counteract the vibrations of the seat frame and occupant transmitted from the helicopter floor in three orthogonal directions. The actuators are controlled by an adaptive feedforward filtered-x least mean square algorithm to cancel the helicopter floor vibration input. The prototype active seat mount design was tested in various configurations with a shaker table providing representative Bell-412 helicopter vibration inputs. Test results demonstrated that the vibrations of the seat frame and mannequin occupant body were suppressed simultaneously, and the major N/rev harmonic peaks of the occupant’s whole-body vibration were reduced by more than 20 dB. This demonstrated that the multiaxis active seat mount design can mitigate the whole-body vibration exposure of the helicopter aircrew to improve their ride quality and reduce adverse health effect.

A Methodology for the Test Design and Evaluation of Human Whole-Body Vibration in Ground Vehicle Systems

1989 ◽  
Vol 33 (18) ◽  
pp. 1192-1196
Author(s):  
Ellen C. Haas
Keyword(s):  
Whole Body Vibration ◽  
International Standards ◽  
Whole Body ◽  
Test Design ◽  
Exposure Limits ◽  
Ground Vehicle ◽  
Body Vibration ◽  
Exposure Limit ◽  
Vehicle Systems ◽  
Iso 2631

To date, testing and evaluation of whole-body vibration in ground vehicle systems have not always fully utilized appropriate experimental design methodology, applicable statistical tests, or relevant criteria. A test design and evaluation methodology was developed to eliminate these oversights. This methodology uses inferential statistics, questionnaires, and a comparison of vibration data with representative mission scenarios. The methodology was employed in the evaluation of two alternative tracked ground vehicle designs. The independent variables were track type, terrain, vehicle speed, and crew position. The dependent variables were International Standards Organization (ISO) 2631 whole-body vibration exposure limit times at the lateral, transverse, and vertical axes. Two different multivariate analyses of variance (MANOVAs) performed on the exposure limit data indicated that all main effects, as well as several interactions, were significant (p < .01). A comparison of exposure limits to a representative mission scenario indicated that both track types would exceed ISO 2631 exposure, comfort, and fatigue limits during expected travel over cross-country terrain. Crew questionnaires also indicated crew discomfort when exposed to this type of terrain. The experiment demonstrated that the procedure was useful in helping to determine the extent that vehicle vibration permits the performance of the vehicle mission, within limits dictated by safety, efficiency, and comfort.

Quantifying The Impact That Coxswain Behaviour Has on Whole Body Vibration - Simulator Trial

2021 ◽  
Vol 163 (A3) ◽  
Author(s):  
T J Newman
Keyword(s):  
Phase 1 ◽  
Whole Body Vibration ◽  
Whole Body ◽  
Motion Platform ◽  
Body Vibration ◽  
Sea Trial ◽  
Data Driven Approach ◽  
Exposure Levels ◽  
Transit Speed ◽  
The Impact

A common risk to personnel is from Whole Body Vibration (WBV) and shock when transiting at speed in heavy seas, and much research has been done by maritime organisations to reduce this risk and the associated health impacts. It is well known that coxswain ‘driving style’ can radically affect exposure levels for a given sea state and sustained transit speed. A data-driven approach to define what makes a good coxswain from a WBV perspective is currently being developed by the Naval Design Partnering team (NDP). In phase 1, a systematic coxswain behaviour tracking methodology has been developed and demonstrated using a motion platform-based fast craft simulator at MARIN. The performance of several experienced volunteer coxswains from MOD, RNLI and KNRM has been evaluated based on a set pattern of tests. The advantages of using the simulator, over a sea trial, have been demonstrated: it is more repeatable, more controllable, accurate and more accessible. The potential disadvantages of the approach are also discussed with reference to feedback gathered from coxswains. Analysis has shown effective throttle control is much more important than steering to reduce WBV. Several interesting trends in WBV reduction potential have been shown which it is thought, with further validation, could aid mission planning, mission execution and provide data for training autonomous feedback/control algorithms. Further work is required before the findings of this study can be fully exploited. These subsequent phases, which include sea trials, aim to provide validation and further evidence to support the initial findings.

scholarly journals Whole Body Vibration Analysis of Baby Hammock

2018 ◽  
Vol 217 ◽  
pp. 01005
Author(s):  
Ying Hao Ko ◽  
Chia Sin Geh
Keyword(s):  
High Speed ◽  
Whole Body Vibration ◽  
Whole Body ◽  
Asian Countries ◽  
Body Vibration ◽  
Limit Value ◽  
Exposure Limit ◽  
Rocking Motion ◽  
Action Value ◽  
Iso 2631

Studies have been carried on the effect of rocking on a baby and concluded that baby sleeps easier while being rocked. In Malaysia, as in many Southeast Asian Countries, it is common to put babies to sleep in a baby hammock. the vertical rocking motion generated by baby hammock has exposed babies to whole-body vibration (WBV). It has been shown by ISO2631 (1997) that WBV may lead the discomfort and adverse effect on health. Standards have been set by ISO 2631 (1997) concerning the WBV for people in a recumbent position and consider weighted vibrations of more than 2 m/s2 to be extremely uncomfortable. However, standards concerning the allowable amount vibrations a baby in a baby hammock can safety endure are currently lacking. WBV analysis of the baby hammock with the weight ranged from 3kg to 14kg is conducted. For each measurement, four conditions are considered: manual rocking, auto rocking with low, medium and high speed. In this study, average root-mean-square values for the acceleration were found to be at a maximum of 2.46 m/s2, and to be above the extremely uncomfortable level. This study develops a baseline exposure time for the baby hammock before it reaches the safety values of exposure action value (EAV) and exposure limit value (ELV) set by ISO 2631(1997).

scholarly journals Assessment of whole-body vibration exposure of mining truck drivers

2020 ◽  
Vol 120 (9) ◽  
Author(s):  
B. Erdem ◽  
T. Dogan ◽  
Z. Duran
Keyword(s):  
Health Effect ◽  
Whole Body Vibration ◽  
Correlation Coefficients ◽  
Dominant Frequency ◽  
Truck Drivers ◽  
Whole Body ◽  
Vibration Acceleration ◽  
Body Vibration ◽  
Dump Trucks ◽  
Iso 2631

SYNOPSIS Whole-body vibration (WBV) exposure measurements taken from 105 truck drivers employed in 19 mines and other workplaces were evaluated with the criteria prescribed in EU 2002/44/EC directive, BS 6841 (1987), ISO 2631-1 (1997). and ISO 2631-5 (2004) standards. The highest vibration acceleration was measured on the vertical Z-axis. The highest WBV exposure occurred in the RETURN, HAUL, and SPOT phases while the lowest exposure took place in the LOAD and WAIT phases. Crest factors on all axes were generally greater than nine, yet strong correlation coefficients were achieved in VDV-eVDV analyses. Driver seats generally dampened the vibration along the Z-axis but exacerbated it along X and Y axes. The dominant frequency for the X and Y-axes rose up to 40 Hz while it ranged between 1 Hz and 2.5 Hz along the Z-axis. While the probability of an adverse health effect was higher with BS 6841 (1987) and ISO 2631-1 (1997) standards, it was low according to EU 2002/44/EC and ISO 2631-5 (2004). The 91 t, 100 t, and 170 t capacity trucks produced lower vibration magnitudes. Drivers were exposed to approximately equivalent levels of WBV acceleration and dose in contractor-type trucks and mining trucks. Rear-dump trucks exposed their drivers to a slightly higher level of vibration than bottom-dump trucks. Underground trucks exposed their drivers to a significantly higher level of vibration than mining trucks. Both driver age and driver experience were inversely proportional to vibration acceleration and dose. Conversely, there was a positive relationship between the truck service years and the WBV acceleration and dose to which drivers were exposed to. Loads of blocky material exposed drivers to higher vibration acceleration and dose levels than non-blocky material. Keywords: whole-body vibration, mining truck, A(8), BS 6841, EU 2002/EC/44, ISO 2631-1, ISO 2631-5, VDV(8).

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