Investigation on the natural frequencies of human organs and body parts

The presence of mechanical oscillatory movements, referred to as vibrations, is clearly and unequivocally found in human activities and in all kinds of technological processes, but this physical phenomenon produces effects that can have negative repercussions on humans and the environment. Numerous studies since the 1960s report that whole-body vibrations (WBV) and hand-arm vibrations (HAV) lead to various diseases, and this has increased interest in studying their causes and assessing the impact of vibrations on health. Today, mechanical vibrations are the fifth most commonly compensated occupational disease in Italy, and for this reason ISO 2631-1 (1997) and ISO 5349-1 (2001) were drafted to provide guidelines on how to correctly measure and interpret WBV and HAV exposure in relation to human health and comfort. Even today, there are countless studies focusing on WBV and HAV in order to further understand the dynamic response of the body and the effect that vibrations may have on it. Based on these considerations, this thesis work focuses on two main aims: -Reviewing the scientific literature in order to reconstruct the resonance frequencies of the human body updated to 2024, summarising the studies of interest. -To realise an MDOF (multi-degree of freedom) model in order to study the dynamic response of the body, in particular with a focus on the resonance frequencies of the head, as the ISO 2631-1 and ISO 5349-1 standards highlight pathologies related to the lumbar spine and neurological and digital circulatory disorders and osteoarticular lesions in the upper limbs, respectively.