THE FATIGUE APPROACH TO VIBRATION AND HEALTH: IS IT A PRACTICAL AND VIABLE WAY OF PREDICTING THE EFFECTS ON PEOPLE?
✍ Scribed by J. Sandover
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 243 KB
- Volume
- 215
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
The fatigue approach assumes that the vertebral end-plates are the weak link in the spine subjected to shock and vibration, and fail as a result of material fatigue. The theory assumes that end-plate damage leads to degeneration and pain in the lumbar spine. There is evidence for both the damage predicted and the fatigue mode of failure so that the approach may provide a basis for predictive methods for use in epidemiology and standards. An available data set from a variety of heavy vehicles in practical situations was used for predictions of spinal stress and fatigue life. Although there was some disparity between the predictive methods used, the more developed methods indicated fatigue lives that appeared reasonable, taking into account the vehicles tested and our knowledge of spinal degeneration. It is argued that the modelling and fatigue approaches combined offer a basis for estimating the effects of vibration and shock on health. Although the human variables are such that the approach, as yet, only offers rough estimates, it offers a good basis for understanding. The approach indicates that peak values are important and large peaks dominate risk. The method indicates that long term r.m.s. methods probably under-estimate the risk of injury. The BS 6841 Wb and ISO 2631 Wk weightings have shortcomings when used where peak values are important. A simple model may be more appropriate. The principle can be applied to continuous vibration as well high acceleration events so that one method can be applied universally to continuous vibrations, high acceleration events and mixtures of these. An endurance limit can be hypothesised and, if this limit is sufficiently high, then the need for many measurements can be reduced.