The significance of using anthropometric parameters and postures of European drivers as a database for finite-element models when calculating spinal forces during whole-body vibration exposure

Modelling the response of the human body to occupational whole-body vibration provides the possibility of predicting the forces acting on the disc and/or endplates of lumbar vertebrae. Due to the complex structure of the human body, complex dynamic models based on human anatomy are required to adequately reflect the dynamic properties of the body. Based on experimental results the influence of posture and stature on the biodynamic behaviour of human subjects is described. To reflect the biodynamic response of different occupational groups of workers exposed to whole-body vibration, an existing model was adapted to five typical different postures and 10 representative statures registered of European drivers of heavy machines. The resulting 50 models were tested with white noise signals in three directions as input to the four interfaces buttock, back, feet, and hands. The results of the static and dynamic shares of the predicted spinal forces at six spinal levels show strong influences of the factors stature and posture. Calculated risk factors to estimate a probability of injuries reflect the influence of these factors. Based on these findings one frequency weighting curve for the assessment of vibration exposure is not sufficient to meet the variability of risks caused by different statures and postures. Relevance to industry The results of the predicted spinal stress and possible health risk can be a basis to improve and to extend the range of measures of prevention, cab and seat design, or vibration isolation of seats. The measures should fit the wide range of spinal stress experienced by different percentile groups and different postures. (c) 2007 Elsevier B.V. All rights reserved.