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Exploring how anthropometric, vehicle and workplace factors influence whole-body vibration exposures during on-farm use of a quad bike
The primary aim of this study is to determine whether a combination of body height, terrain and vehicle mechanical factors confound for the effect of body mass on WBV exposure while using a quad bike under normal rural working conditions. A seat pad mounted triaxial accelerometer and data logger recorded full work day vibration and shock data from 130 New Zealand rural workers. Personal, vehicle and workplace characteristics were gathered using a modified version of the Whole Body Vibration Health Surveillance Questionnaire. Whole-body vibrations were analysed in accordance with the ISO 2631-1...
The presence of a backrest changes the biodynamic response of the seated body and should be taken into account
This study investigated the apparent mass and cross-axis apparent mass of the human body exposed to random vibration (0.2 to 20 Hz) in all 15 possible combinations of four magnitudes (0, 0.25, 0.5 and 1.0 ms–2 r.m.s.) of fore-and-aft vibration and the same four magnitudes of vertical vibration. The human body has a nonlinear response to wholebody vibration: a softening response as the magnitude of vibration increases. The nonlinearity is apparent when the body is excited at varying magnitudes of single-axis vibration and when the body is excited by a fixed magnitude of vibration in one axis...
An approach to the control system design of seat suspension systems for the active vibration attenuation
This paper presents an approach to the control system design of seat suspension systems for the active vibration attenuation. The paper presents the studies of the active vibration control strategy based on the reverse dynamics of force actuator and the primary controller. The multi-criteria optimization procedure is utilized in order to calculate the primary controller settings which subsequently define the vibro-isolation characteristics of active suspensions. As an example of the proposed control system design, the seat with a pneumatic suspension is investigated and its vibro-isolation properties...
Whole body- vibration (WBV) levels remained just above ISO 2631-1 after being optimized for load-haul-dump (LHD) vehicles
Operators of load-haul-dump (LHD) vehicles are commonly exposed to wholebody- vibration (WBV) levels above ISO 2631-1 and EU Directive 2002/44/EC guidelines. Vibration exposure was lowest when the LHD was driven at the lowest speed, forward, over smooth terrain, with ride control on and the bucket loaded (0.20 m/s 2 ). The A(8) decreased from 0.84 m/s 2 when driving with ride control off, over mixed terrain using all gears, to 0.53 m/s 2 when driving with ride control on and an optimized seat. The estimated daily exposure decreased but remained just above the ISO 2631-1 and EU Directive 2002/44...
Workload is elevated with whole-body vibration, without getting affected by backrest angle.
This study investigated the effects of reclined backrest angles on cognitive and psycho-motor tasks during exposure to vertical whole-body vibration. Apart from 22.5° seat backrest angle for the tracking task, backrest angle did not adversely affect the performance during vibration. However, participants required increased effort to maintain performance during vibration relative to the stationary condition. These results suggest that undertaking tasks in an environment with vibration could increase workload and risk earlier onset of fatigue. Source: The influence of seat backrest angle on human...
Damper with optimised progressive damping characteristic is better at shock mitigation than suspended commercial seat as presently available
A single degree-of-freedom simulation model of a seat equipped with a non-linear fore-and-aft suspension system was developed. The performance of a typical fore-and-aft suspension system was analysed using typical vibration and shock acceleration signals measured in loaders while travelling on off-road terrain and while driving the bucket into a heap of soil. The simulations are of use to seat manufacturers in developing improved fore-and-aft seat suspension for wheel loaders. Source: Study of simultaneous shock and vibration control by a fore-and-aft suspension system of a driver’s seat...
Study recommandations to greatly reduce the transmission of vertical vibration to the operator.
Vibratory soil compactors are articulated vehicles designed to achieve efficient compaction of the soil and road base-layers through a vibratory drum/roller integrating an unbalanced rotating mass. The low frequency whole-body vibration are directly transmitted to the operator through the driver seat, which in the vast majority of the vehicles employed in Québec is limited to a polyurethane foam cushion. The results of this study suggest that the seat and the cabin mounts amplify the low frequency vibration for all the vehicles considered but this amplification is limited for the 13-ton...
A predictive discomfort measure of seated subjects is proposed to assess discomfort in complicated environments and to develop reliable biodynamic models.
A predictive discomfort measure considering the combined neck and trunk is introduced in this work and compared with the seat-to-head transmissibility and subjective reported discomfort due to fore-aft whole-body vibration of seated subjects under two sitting postures. The proposed discomfort quantifies whole-body musculoskeletal discomfort considering body posture, closeness of the joints to their limits, and severity of the angular acceleration at the joints. The proposed predictive discomfort captured the trend of the subjective reported discomfort and showed good potential to capture the effect...
Whole-Body Vibration - Building Awareness in Safety, Health & Environment
Issues in the U.S. include inadequate professional awareness and knowledge of WBV, limited exposure assessment data and lack of mandatory standards. Whether transmitted during standing or sitting, whole-body vibration (WBV) is a hazardous exposure that is common in many occupational settings. It can lead to low-back pain and lost time in occupational environments. Yet, as often as it may occur, a recent survey revealed that issues surrounding WBV are not known to many SH&E professionals. However, implementing practices such as seat redesign and exposure assessments can address this knowledge...
Développement d’un prototype de siège pour opérateur de métro dans un contexte où l’espace est très restreint
Cette étude porte sur le développement d'un prototype de siège d'opérateur de métro permettant d'atténuer les vibrations et d'améliorer le confort, tout en convenant à l'espace très restreint de la loge de conduite. Le siège actuellement utilisé (strapontin) et conçu il y a une trentaine d'années, s'avère insatisfaisant : il est de confection rudimentaire et amplifie les vibrations. Cette étude fait suite à l'analyse ergonomique et vibratoire du poste d'opérateur...

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