Whole-Body Vibration Testing
At a glance
Vehicles are operated in various conditions and their occupants experience vibrations transmitted through the seat and floor. Millbrook measures and assesses the vibrations and noise against Health and Safety Executive (HSE) guidance for whole-body vibration, hand-arm vibration and workplace noise.
Whole Body Vibration Measurement
An operator of all-terrain vehicles required the measurement of vibrations and noise experienced by the occupants during normal usage. This was to determine if any action was required to limit occupant exposure to whole-body vibration, hand-arm vibration and work place noise.
The operator needed to understand if the vehicles met legal obligations to their employees and to identify any changes required to improve working conditions. They also wanted to identify any changes required to improve operational efficiency of the machinery.
Millbrook performed whole-body vibration testing, hand-arm vibration measurement and workplace noise assessment using precision microphones and tri-axial accelerometers. The levels of occupant exposure to noise and vibration were measured against definitions provided by the HSE. Millbrook tested 13 different vehicles for the vehicle operator.
Whole-Body Vibration Test Procedure
Millbrook’s proving ground in the UK offers a variety of purpose-built test track surfaces used to generate different inputs into the vehicle with a high degree of repeatability. This allowed Millbrook to take measurements which are representative and comparable across multiple vehicles.
A variety of on- and off-road test surfaces were defined by Millbrook as part of the test procedure. These were driven over at different vehicle speeds to replicate normal vehicle usage. Measurements for noise and vibration were also taken at occupant locations to calculate exposure levels. Where appropriate, Anthropomorphic Test Dummies (ATDs) were used to ensure that the measurements were representative of in service conditions.
The number of channels required differed depending on the vehicle, with up to 191 channels recorded simultaneously at a sampling rate of 50kHz. During data collection, vehicles were driven following clearly defined test instructions by suitably qualified drivers, ensuring repeatability.
The whole-body vibration, hand-arm vibration and workplace noise levels derived from the data analysis were used to calculate the exposure times using the HSE guidelines. Using Millbrook’s reports, the customer was able to make changes to the vehicles to ensure they met HSE guidelines.