A well-designed seat for drivers and passengers in vehicles such as cars, trains, buses, aircraft or marine craft is essential for the safety, health and comfort of the occupant. This is no less so for operators of plant and heavy machinery such as tractors and earth-moving equipment or military transport vehicles where off-road travel over rough and uneven terrain causes harsh vibration.
Whole body vibration (WBV) transmitted through a seat can cause discomfort or numbness, particularly in the lower back and spine. With prolonged, frequent and repeated exposures, lower back pain and other musculoskeletal disorders may result, particularly in professional drivers, and particularly if the seat does not support good posture. Vibration, particularly shocks or jolts, may also aggravate pre-existing injuries.
Low-frequency vibration may induce motion sickness. Other effects may include fatigue, stress and lack of concentration. In extreme cases, vibration can affect performance and make the reading of displays or the use of controls difficult. Even when vibration is low, it can be inconvenient, for example, when typing a text message or a website URL into a mobile phone in a moving bus.
Under some conditions and at some frequencies a poorly designed seat, rather than isolating the sitter, can actually amplify vibration.
Testing allows manufacturers to
- quantify how well a seat isolates or transmits vibration to the sitter.
- assess ride comfort
- optimise design and refine seat suspension, padding and materials for a specific type of vehicle and use
- protect operators of heavy machinery and professional drivers from long-term health risks and ensure compliance with safety standards or regulations.
Watch a short video of vibration testing of a suspension seat (2 min 14 s)
Vibration testing
We carry out laboratory and field tests of the vibration transmissibility of seats for vehicle and seat manufacturers. In our Vibration Test Laboratory, we use the ISVR Six-Axis Motion Simulator or the 1 metre single-axis electro-hydraulic simulator pictured above, depending on the requirement. Test procedures are in accordance with national and international standards or can be tailored to customer requirements. Tests can be undertaken with human subjects or an anthropodynamic dummy, depending on the requirements of the particular standard or test procedure used.
Tests are carried out in accordance with the following standards:
- ISO 10326-1:2016 Mechanical vibration — Laboratory method for evaluating vehicle seat vibration. Part 1: Basic requirements. (Applies to any type of seat used in vehicles and mobile off-road machinery.)
- ISO 10326-2:2022 Mechanical vibration — Laboratory method for evaluating vehicle seat vibration. Part 2: Application to railway vehicles. (This covers seats designed for passengers or crew.)
- ISO 7096:2020 Earth-moving machinery — Laboratory evaluation of operator seat vibration.
- ISO 5007:2003 Agricultural wheeled tractors — Operator’s seat — Laboratory measurement of transmitted vibration.
- EN 13490:2001+A1 Mechanical vibration — Industrial trucks — Laboratory evaluation and specification of operator seat vibration.
We have equipment capable of performing indenter measurements of seats and seat components to obtain:
- Quasi-static force-deflection characteristics
- Dynamic stiffness characteristics
Contact us
ISVR Consulting is an Enterprise Unit linked to the Institute of Sound and Vibration Research at the University of Southampton. We work with a wide range of industrial and commercial clients, public bodies, and government agencies in the UK and Europe.
ISVR Consulting carries out tests on behalf of clients and has a wide range of specialist acoustical instrumentation and audio test equipment available . Our staff normally conduct the tests, but you can also hire the chamber to carry out your own testing with your own instrumentation, with our expertise on hand should you need it.
ISVR Consulting has produced a downloadable guide to test facilities in pdf format. This gives additional information on cable ports, single- and three-phase electrical supplies, workshop facilities, air supplies, access and dimensions, etc. The guide is intended to assist clients wishing to test large pieces of equipment.
Get in touch to find out more about our facilities and how we might be able to work with you.
Tel: +44 (0) 2380 592162 email: consulting@isvr.co.uk web: https://isvr.co.uk
Address: ISVR Consulting, Building 15 (M27), University of Southampton, University Road, Southampton, SO17 1BJ.
Location: https://what3words.com/focus.shovels.affair
There are detailed directions to our location on our ‘Contact Us‘ page.
