On Using the ISO Standard To Evaluate the Ride Quality of Broad-Band Vibration Spectra in Transportation Vehicles

1976 ◽  
Vol 98 (4) ◽  
pp. 440-443 ◽  
Author(s):  
Craig C. Smith
Keyword(s):  
Broad Band ◽  
International Standards ◽  
Whole Body ◽  
Ride Quality ◽  
Iso Standard ◽  
Vibration Data ◽  
Power Spectral ◽  
Country Road ◽  
International Standards Organization ◽  
Iso 2631

The International Standards Organization “Guide for the Evaluation of Human Exposure to Whole-Body Vibrations”, ISO 2631, is converted to a form usable for direct comparison with vibration data represented in power spectral density form. Comparisons are made between the ISO standard, the Urban Tracked Air Cushion Vehicle (UTACV) specification, and measured vibrations at the floorboard and seat of an automobile over smooth and rough roads. The data indicate that the ISO standard is less restrictive than the UTACV specification, and generally not restrictive enough to indicate the roughness of an automobile ride on a rough country road.

scholarly journals International Standards Organization-Compatible Index for Pavement Roughness

1998 ◽  
Vol 1643 (1) ◽  
pp. 110-115 ◽  
Author(s):  
A. T. Papagiannakis ◽  
B. Raveendran
Keyword(s):  
Unit Length ◽  
International Standards ◽  
Whole Body ◽  
User Cost ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Reference Vehicle ◽  
Roughness Index ◽  
Pavement Damage ◽  
International Standards Organization

The development of a new pavement roughness index, which is compatible to the current International Standards Organization (ISO) standard on “exposure to whole-body vibration” is described. The index was intended to be the independent variable in the future development of relationships between user cost (i.e., vehicle depreciation, repairs, discomfort and so on) and pavement roughness; hence it was named RIDE (Roughness Index for Driving Expenditure). RIDE is based on the sprung mass acceleration response of a reference vehicle to the pavement profile. It is calculated in the frequency domain by multiplying the power spectral density (PSD) of the pavement profile by the square of the transfer function of the sprung mass acceleration of the reference vehicle. The resulting sprung mass acceleration PSD is integrated over frequency to yield the root-mean-square of the sprung mass acceleration per unit length of pavement traveled. The sprung mass acceleration is shown to be the main contributor of dynamic axle loads in heavy trucks, which relate to vehicle and cargo damage and also to pavement damage.

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.

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.

A comparative study of transmissibility factors of traditional and pneumatic dumper seats using one-third octave band analysis

2020 ◽  
Vol 51 (10) ◽  
pp. 167-175
Author(s):  
Bibhuti B Mandal ◽  
Ashis Bhattacharjee ◽  
Shivkumar Prajapati ◽  
Syed Aftab Hussain
Keyword(s):  
Control Measures ◽  
Whole Body ◽  
Octave Band ◽  
Vibration Signals ◽  
Vibration Data ◽  
Rigid Frame ◽  
Vibration Transmissibility ◽  
Opencast Mines ◽  
Significant Attenuation ◽  
Iso 2631

Severity of exposure to whole-body vibration of vehicle drivers depends on multiple factors including type of vehicle suspension or quality of seats. The study presents analysis of seat vibrations of two different types of dumpers in opencast mines. Since health guidance provided in ISO 2631-1997 are only indicative, seat effective amplitude transmissibility factors along with one-third octave-band analysis of vibration signals have been considered as more effective information for control measures. Vibration characteristics of conventional seats ( n = 3) with rigid frame and those with pneumatic suspensions ( n = 3) have been compared during their use in mines. A(8) values ranged from 0.66 to 1.41 m/s2. All the six operators had shown moderate to higher health risk but this may vary since both intensity and durations of exposure frequently change during the operators’ employment. Vibration signals from a mono-axial accelerometer (z′) placed on the cabin floor was captured in addition to three channel vibration data (x, y and z) of a seat pad accelerometer placed on the vehicle seat. Transmissibility analysis of vibration signals from cabin floor to seat surface showed that the three pneumatic seats resonated in the range of 1.6–2.5 Hz in the z axis. There was significant attenuation of vibration energy ranging from 37% to 63% at 4 Hz which is important in the context of spinal injuries. The seat effective amplitude transmissibility values (%) in the resonating frequencies ranged from 119% to 173%. Interestingly, the conventional seats resonated at 4–5 Hz and the corresponding seat effective amplitude transmissibility (%) values were varying from 128% to 163%. This resonance at 4 Hz is in sharp contrast with the behaviour of pneumatic seats. It is recommended that vibration transmissibility should be considered as a major design parameter for mining vehicle seats.

scholarly journals The Prediction of Passenger Riding Comfort From Acceleration Data

1978 ◽  
Vol 100 (1) ◽  
pp. 34-41 ◽  
Author(s):  
C. C. Smith ◽  
D. Y. McGehee ◽  
A. J. Healey
Keyword(s):  
Subjective Evaluation ◽  
Evaluation Criteria ◽  
International Standards ◽  
Ride Quality ◽  
Vibration Spectra ◽  
Passenger Seat ◽  
Absorbed Power ◽  
Air Cushion ◽  
Frequency Weighting ◽  
International Standards Organization

Various methods for evaluating ride quality in automobiles are investigated by means of a field study involving two different automobiles, seventy-eight different passengers, and eighteen different raodway sections. Passenger rating panels were used to obtain subjective evaluation of the various rides, and measured vibration spectra were examined on the basis of various frequency weighting techniques to determine their ability to predict the subjective ratings. Included in the evaluation criteria considered are weighting functions derived from the ISO (International Standards Organization) Standard, the UTACV (Urban Tracked Air Cushion Vehicle) Specification, and the Absorbed Power method of Lee and Pradko. Excellent correlation was found to exist between the subjective ride ratings and simple root mean square acceleration measurements at either the vehicle floorboard or the passenger/seat interface. Equations are presented to predict the subjective ride rating from measured vibration spectra.

scholarly journals Development, validation, and pilot MRI safety study of a high-resolution, open source, whole body pediatric numerical simulation model

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0241682
Author(s):  
Hongbae Jeong ◽  
Georgios Ntolkeras ◽  
Michel Alhilani ◽  
Seyed Reza Atefi ◽  
Lilla Zöllei ◽  
...  
Keyword(s):  
Brain Structures ◽  
International Standards ◽  
Whole Body ◽  
Synthetic Image ◽  
Mri Safety ◽  
Older Children ◽  
Implantable Medical Device ◽  
Tissue Compartments ◽  
International Standards Organization ◽  
Age Range

Numerical body models of children are used for designing medical devices, including but not limited to optical imaging, ultrasound, CT, EEG/MEG, and MRI. These models are used in many clinical and neuroscience research applications, such as radiation safety dosimetric studies and source localization. Although several such adult models have been reported, there are few reports of full-body pediatric models, and those described have several limitations. Some, for example, are either morphed from older children or do not have detailed segmentations. Here, we introduce a 29-month-old male whole-body native numerical model, “MARTIN”, that includes 28 head and 86 body tissue compartments, segmented directly from the high spatial resolution MRI and CT images. An advanced auto-segmentation tool was used for the deep-brain structures, whereas 3D Slicer was used to segment the non-brain structures and to refine the segmentation for all of the tissue compartments. Our MARTIN model was developed and validated using three separate approaches, through an iterative process, as follows. First, the calculated volumes, weights, and dimensions of selected structures were adjusted and confirmed to be within 6% of the literature values for the 2-3-year-old age-range. Second, all structural segmentations were adjusted and confirmed by two experienced, sub-specialty certified neuro-radiologists, also through an interactive process. Third, an additional validation was performed with a Bloch simulator to create synthetic MR image from our MARTIN model and compare the image contrast of the resulting synthetic image with that of the original MRI data; this resulted in a “structural resemblance” index of 0.97. Finally, we used our model to perform pilot MRI safety simulations of an Active Implantable Medical Device (AIMD) using a commercially available software platform (Sim4Life), incorporating the latest International Standards Organization guidelines. This model will be made available on the Athinoula A. Martinos Center for Biomedical Imaging website.

Evaluating Passenger Railway Ride Quality Over Long Distances Using Smartphones

2020 ◽  
Author(s):  
Ngoan Tien Do ◽  
Parisa Haji Abdulrazagh ◽  
Mustafa Gül ◽  
Michael T. Hendry ◽  
Alireza Roghani ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Low Cost ◽  
Ride Quality ◽  
Level Crossing ◽  
Future Plan ◽  
Vibration Data ◽  
The Future ◽  
Smartphone Sensors ◽  
Iso 2631

Abstract This paper presents a smartphone-based ride quality assessment conducted on a VIA Rail route in the province of Ontario Canada. The vibration data were collected by different smartphones placed in different locations on the train. The levels of ride quality were subsequently quantified by the two commonly used indices recommended in the ISO 2631:1-1997, and BS EN 12299:2009 standards. The results show that using smartphones for ride quality yields reasonable assessment in a low-cost and convenient manner and identify that the major poor ride quality values are recorded at stiffness transitions such as bridges, level crossing and switches. Limitations of smartphone sensors, and the future plan for improvement of the use of smartphones for evaluation of ride quality has also been discussed.

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.

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