The benefit of modal analysis for whole body vibration models

Whole body vibrations are usually characterized in terms of transfer functions, such as impedance or apparent mass. Data measurements from subjects are averaged and analyzed with respect to certain attributes (anthropometry, posture etc.). Averaging includes the risk of identifying unnatural vibration characteristics. The use of a modal description as an alternative method is presented and its contribution to biodynamic modeling is discussed. From experimental data, modal parameters are identified which can easily be used to set up a mathematical model. This model will provide the vibration behavior relating to the input data. Phenomenological models, such as hardware vibration dummies, are based on this approach and a selection will be introduced. Finite element models, which employ an anatomical approach, aim to simulate the vibration response of the human body. They supply mechanical parameters within the body which are relevant to effects on the health and comfort sensations of humans. Modal analysis of the computed results can make simulation and experimental data comparable and supports the validation process of software models.