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Publication AbstractsModels of the Apparent Mass of the Seated Human Body Exposed to Horizontal Whole-Body VibrationN. J. Mansfield, Ph.D., B.Eng., and R. Lundström, Ph.D., M.Sc.Aviat Space Environ Med 1999; 70:1166-72 AbstractBackground: Many environments contain vibration with simultaneous vertical and horizontal components. Mathematical lumped parameter models of the mechanical impedance of the seated human body have previously been defined for exposure to vertical vibration. This paper proposes models for the response of the seated body when exposed to horizontal vibration. Methods: Four target functions were derived from previously reported measurements of the apparent masses of seated subjects exposed to fore-and-aft and lateral vibration at both 0.5 and 1.0 ms-2 r.m.s. Parameters were optimized for six different three degree-of-freedom models to fit the modulus of the model responses to the four target functions. Results: The modulus and phase of the apparent masses optimized for all combinations of vibration magnitude and direction were close to the responses previously measured and reported in the literature. Fitted parameters for all models with elements in series showed at least one element with a parameter that tended to zero. Conclusions: Models with three parallel single degree-of-freedom systems with a rigid support generally gave the closest representation of the apparent mass of the seated body exposed to horizontal vibration. More experimental data on the effect of gender, posture and magnitude of vibration on the apparent masses of seated subjects would be useful to enable these models to be improved.Keywords: modelling, whole-body vibration, horizontal, apparent mass. Information on subscribing, and on obtaining copies of an article or of an entire issue. Table of Contents for Volume 70, Number 12 of the ASME journal.
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