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Master of Science




Dickey, James P.


Professional drivers are at a high risk of WBV injury as they are exposed to vibration constantly throughout a working day. Recently a company has attempted to mitigate the risk by developing an active suspension seat aimed at reducing WBV exposure for long haul truck drivers. The purpose of this thesis was to compare the new active suspension technology to the current industry standard passive suspension seat. Seats were tested with Random vibration exposures and exposures simulating Canadian long-haul trucks. Seats were evaluated by A(8) daily vibration exposure and peak transmissibility metrics. The results determined that the active suspension is significantly more effective in attenuating z axis vibration at the frequencies that are most impactful on human health. However, both seats A(8) daily vibration exposures were below the ISO 2631-1 HCGZ caution limit. This suggests that there is no difference in health risks between seats.

Summary for Lay Audience

Whole body vibration (WBV) is a term describing any vibration that is transmitted to the human body from supporting surfaces. The average individual can be exposed to WBV regularly throughout their day such as when driving a car. Chronic WBV exposure has been linked to negative health effects such as digestive disorders, sciatica, prostate cancer, low back pain, and musculoskeletal disorders. Professional drivers are exposed to WBV throughout their workday and because of this have documented higher occurrences of low back pain compared to professionals that are exposed to less WBV.

One solution for limiting WBV for professional drivers has been the implementation of suspension seats. Every long-haul truck has a suspension seat equipped in order to attenuate (reduce) the vibration exposure for the operator. It is common for these suspension seats to have dampers in the form of an air spring. These types of seats are called passive seats. Recently, there has been a development of a new suspension seat technology regarded as being more effective at reducing WBV exposure. This active seat suspension technology includes an actuator that works with an air spring to reduce vibration. The purpose of this research was to compare active and passive suspension seats in order to determine what technology is more effective at reducing WBV. We tested these seats with random vibration exposures and vibration exposures that simulated long-haul trucks on Canadian roads. We determined that the active suspension seat was better at reducing the vibration in the z axis (vertical axis) compared to the older style passive suspension seat. When we stimulated a Canadian truck driver’s full work day exposure level of WBV, both seats attenuated the exposures to the point where health risks were reduced. Therefore, although the active suspension seat was better at reducing WBV. Ultimately, the current industry standard seat is sufficient for attenuating vibration on Canadian roads.

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Biomechanics Commons