Human-structure interaction experiments to determine the dynamic properties of the standing human body in vertical vibration

This paper presents an experimental investigation to identify the fundamental vertical dynamic parameters (natural frequency, damping ratio and body mass ratio) of the standing human body on a vibrating single degree-of-freedom (SDOF) structure. The human whole-body model was previously derived based on the theory of human-structure interaction. Two groups of people participated in the experiment. The groups consisted of 18 and 38 people and measurements were taken for two different settings of the test rig and at two vibration levels. These experiments consistently showed two resonance frequencies of the highly damped human-structure system. The study demonstrated that the experiments were repeatable; and the dynamic parameters of the standing subjects were independent of the test rig setup and the gender of the subjects. It was also observed that the vibration magnitude had a significant effect on the natural frequency but not on the damping ratio. The mean fundamental natural frequency and damping ratio of the standing human body were approximately 6.6 Hz and 22% in vertical vibrations. This is the first time that the dynamic properties of the standing human body have been determined based on the theory of human-structure interaction.