An attempt to estimate natural frequencies of parts of the child's body

Abstract

Recently, particular attention has been increasingly often paid by researchers to the children that are transported in safety seats as such children should be treated with no less care than "normal" passengers would, especially in the case of long-distance travels. The issue of the influence of vibrations on adult's bodies has been relatively well described, which is reflected in numerous normative acts [S1 to S13]. For children, however, the studies on these issues are still at an early stage. We may state, therefore, that the evaluation of ride comfort with respect to small children whose anthropological characteristics differ from those of adults is still an open question [1]. In this paper, the issue of natural frequencies of parts of the human body has been raised and attention has been drawn to the lack of data about natural frequencies of parts of the child.s body. A method has been proposed that would make it possible to estimate the frequencies of free vibration of organs and parts of the child's body, based on data collected from adults. A computational method to estimate the natural frequencies of parts of the body has been presented. Results of experimental road tests carried out with the use of dummies representing an adult (HYBRID II) and a child, made at PIMOT, have been included.