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 A study of vibration exposure and work practices of Loader and Dozer operators in opencast mines

2012 ◽  
Vol 2 (2) ◽  
pp. 3-7 ◽  
Author(s):  
Bibhuti Bhusan Mandal ◽  
Krishnendu Sarkar ◽  
Veena Manwar
Keyword(s):  
Health Risk ◽  
Occupational Safety ◽  
Vertical Direction ◽  
Control Measures ◽  
Whole Body ◽  
Reverse Direction ◽  
Work Practices ◽  
Continuous Change ◽  
Background Exposure ◽  
Opencast Mines

Background: Exposure to whole body vibration (WBV) at work and development of musculoskeletal disorders are well linked. Vehicle vibrations are usually perceived to occur in vertical direction and are likely to cause lumbar disorders in operators. Vibration characteristics of the machines need to be studied and compared with work practices which may indicate nature of health risk to operators. This may help in developing specific action plans to control vibration related health risk. Objective: The objectives of the study were, to measure and analyze vibration magnitudes, observe work practices of Loaders and Dozers, evaluate health risk to their operators and to formulate recommendations for control measures. Methods and Material: Frequency weighted Root Mean Square values of acceleration data was collected as per guidelines in ISO 2631-1:1997 using human vibration analyzers. WBV exposure of 40 (Forty) Loader and Dozer operators in eight opencast mines were evaluated to assess health risk using vibration magnitude and corresponding daily exposure durations. Results and Conclusion: The dominant axis of vibration in dozers was found to be X (front to back) in 80% of the equipments. This is different from transporting equipment like Dumpers which have Z axis as dominant axis of vibration. A continuous change of movement in forward and reverse direction and rash driving were found to be contributory factors for increased vibration intensity along X- axis. It was observed that 27(68%) of them showed moderate whereas 12(30%) equipment showed high health risk. It is suggested that vibration control measures should be designed and adopted based not only on the intensity but also on the dominant axis typical to the equipment and work practices.DOI: http://dx.doi.org/10.3126/ijosh.v2i2.6144 International Journal of Occupational Safety and Health, Vol 2. No 2 (2012) 3-7 

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 Evaluation of Bus Vibration Comfort Based on Passenger Crowdsourcing Mode

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Hong Zhao ◽  
Li-Lu Guo ◽  
Xiang-Yan Zeng
Keyword(s):  
Evaluation System ◽  
Experimental System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Vibration Signals ◽  
Vibration Data ◽  
Low Pass ◽  
Space Coordinate ◽  
Iso 2631

Vibration comfort is an important factor affecting the quality of service (QoS) of bus. In order to make people involved in supervising bus’s vibration comfort and improve passengers’ riding experience, a novel mode of passenger crowdsourcing is introduced. In this paper, comfort degree of bus vibration is calculated from bus’s vibration signals collected by passengers’ smartphones and sent through WiFi to the Boa web server which shows the vibration comfort on the LCD deployed in bus and maybe trigger alarm lamp when the vibration is beyond the threshold. Three challenges here have been overcome: firstly, space coordinate transformation algorithm is used to solve the constant drift of signals collected; secondly, a low-pass filter is designed to isolate gravity from signals real-timely via limited computing resources; thirdly, an embedded evaluation system is developed according to the calculation procedure specified by criterion ISO 2631-1997. Meanwhile, the model proposed is tested in a practical running environment, the vibration data in whole travel are recorded and analyzed offline. The results show that comfort degree of vibration obtained from the experimental system is identical with the truth, and this mode is proved to be effective.

scholarly journals Effect of Wheelchair Frame Material on Users’ Mechanical Work and Transmitted Vibration

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Félix Chénier ◽  
Rachid Aissaoui
Keyword(s):  
Current Knowledge ◽  
Whole Body Vibration ◽  
Mechanical Work ◽  
Whole Body ◽  
Shoulder Injury ◽  
Body Vibration ◽  
Significant Difference ◽  
Current Belief ◽  
Vibration Transmissibility ◽  
Iso 2631

Wheelchair propulsion exposes the user to a high risk of shoulder injury and to whole-body vibration that exceeds recommendations of ISO 2631-1:1997. Reducing the mechanical work required to travel a given distance (WN-WPM, weight-normalized work-per-meter) can help reduce the risk of shoulder injury, while reducing the vibration transmissibility (VT) of the wheelchair frame can reduce whole-body vibration. New materials such as titanium and carbon are used in today’s wheelchairs and are advertised to improve both parameters, but current knowledge on this matter is limited. In this study, WN-WPM and VT were measured simultaneously and compared between six folding wheelchairs (1 titanium, 1 carbon, and 4 aluminium). Ten able-bodied users propelled the six wheelchairs on three ground surfaces. Although no significant difference of WN-WPM was found between wheelchairsP<0.1, significant differences of VT were foundP<0.05. The carbon wheelchair had the lowest VT. Contrarily to current belief, the titanium wheelchair VT was similar to aluminium wheelchairs. A negative correlation between VT and WN-WPM was found, which means that reducing VT may be at the expense of increasing WN-WPM. Based on our results, use of carbon in wheelchair construction seems promising to reduce VT without increasing WN-WPM.

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.

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).

scholarly journals SHIP-MR and Radiology: 12 Years of Whole-Body Magnetic Resonance Imaging in a Single Center

Healthcare ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
Norbert Hosten ◽  
Robin Bülow ◽  
Henry Völzke ◽  
Martin Domin ◽  
Carsten Oliver Schmidt ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Population Based ◽  
Scientific Output ◽  
Control Measures ◽  
Whole Body ◽  
Body Parts ◽  
Scientific Publications ◽  
Scientific Outputs ◽  
Northeastern Germany ◽  
The Brain

The Study of Health in Pomerania (SHIP), a population-based study from a rural state in northeastern Germany with a relatively poor life expectancy, supplemented its comprehensive examination program in 2008 with whole-body MR imaging at 1.5 T (SHIP-MR). We reviewed more than 100 publications that used the SHIP-MR data and analyzed which sequences already produced fruitful scientific outputs and which manuscripts have been referenced frequently. Upon reviewing the publications about imaging sequences, those that used T1-weighted structured imaging of the brain and a gradient-echo sequence for R2* mapping obtained the highest scientific output; regarding specific body parts examined, most scientific publications focused on MR sequences involving the brain and the (upper) abdomen. We conclude that population-based MR imaging in cohort studies should define more precise goals when allocating imaging time. In addition, quality control measures might include recording the number and impact of published work, preferably on a bi-annual basis and starting 2 years after initiation of the study. Structured teaching courses may enhance the desired output in areas that appear underrepresented.

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.

scholarly journals Evaluation of Health Risk Level of Hand-Arm and Whole-Body Vibrations on the Technical Operators and Equipment in a Tobacco-Producing Company in Nigeria

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Oluseyi Adewale Orelaja ◽  
Xingsong Wang ◽  
Dauda Sh. Ibrahim ◽  
Umer Sharif
Keyword(s):  
Whole Body ◽  
Risk Level ◽  
Time Frequency ◽  
Daily Exposure ◽  
Limit Value ◽  
Exposure Limit ◽  
High Acceleration ◽  
External Forces ◽  
Secondary Manufacturing ◽  
Iso 2631

Vibration is experienced when a body is subjected to either internal or external forces which cause oscillation, with most operators of industrial equipment often exposed to high dosage, higher than the stipulated values. In this research, Digital Real-Time Frequency Analyzer (RSA 5106A) was used, while the results obtained were evaluated and compared with the health guidelines of the ISO 2631-1 : 1997 and ISO 2631-5 : 2004 standards, as described in the Health Guidance Caution Zone for a daily exposure action value (EAV) of 0.47 m/s2 and a daily exposure limit value (ELV) of 0.93 m/s. High acceleration was mostly seen on the z-axis in all the results obtained, whereas many were not within the HGCZ (Arms <0.47, and >0.93 m/s2). Comparing (VDV <8.5 m/s1.75 and >17 m/s1.75) with the ISO standard, the accelerations on all x- and y-axes were slightly within the HGCZ, with just a little below 0.47 m/s2 limit. The results obtained clearly showed that urgent action is needed virtually on all the equipment in both the Secondary Manufacturing Department (SMD) and Primary Manufacturing Department (PMD) to minimize vibration exposure on the technical operators.

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