Bicycle helmet vibrations and relation to helmet dislodgement during normal road use
Bicycle safety helmets suffer accelerations up to 30 m/s**2 under normal riding conditions. The direction of these accelerations appears to be fairly random. During more major shocks, accelerations of 100 m/s**2 can be encountered. In assessing the forces involved on the helmet, the worst case would consider the head in a forward horizontal position with gravitational acceleration aiding vibrational acceleration. Thus 9.8 M/s**2 can be added to the values obtained. For the worst case, using 40 m/s**2 and 450 to 600 g as the typical range of helmet mass, the forces involved in moving the helmet under normal road vibrations are thus up to about 18 to 24 n. These are therefore the minimum forces to be considered in any test to ascertain the likelihood of forward helmet dislodgement to obscure the vision. From the results for the more major shocks, it appears that 65 n should be set as the minimum force to be considered for a forward rotation test involving helmet removal. At this stage measurements have been made only by a single rider using a single helmet model. It is recommended that this work be extended to cover a greater variety of riders and helmets. It is also recommended that the instantaneous vibrational waveforms be studied to separate action and reaction.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/644061219
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Authors:
- Mathieson, J G
- Coin, C D
- Conference:
- Publication Date: 1987
Language
- English
Media Info
- Pagination: 577-8
- Monograph Title: Bicycle roughness issues, and the effective use of designated cycle facilities
Subject/Index Terms
- TRT Terms: Cyclists; Helmets; Speed; Vibration
- ATRI Terms: Cyclist; Helmet; Speed; Vibration
- Subject Areas: Pedestrians and Bicyclists; Safety and Human Factors;
Filing Info
- Accession Number: 01428876
- Record Type: Publication
- Source Agency: ARRB
- ISBN: 644061219
- Files: ATRI
- Created Date: Aug 24 2012 3:03PM