Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Dr. Thomas Jenkyn

Abstract

With the mortality, disability and socioeconomic costs associated with head injury, head impact biomechanics is important to developing injury criterions and safety tolerances. However, the current state of knowledge is contradictory and vague. This thesis will contribute to research done on the vibrational response of the head to impact by discussing two studies. The first will describe the design, implementation and validation of a head impactor setup specific for the study of the frequency response of the skull. An impactor capable of producing sub-5ms duration, sub-fracture impacts was successfully designed. The apparatus was validated by comparing the results of a protocol to the results published in established literature and a repeatability study was done to prove the repeatability and reproducibility of the impactor. The second part discusses the effects of various factors on the frequency response of the head. Strain gauge data was transformed to the frequency domain and frequency peaks were extracted. Resonant frequencies were then identified by a cluster analysis. ANOVA tests were used to determine the significance of factors on changes to the frequency response. Individual specimen differences were found to have a significant effect on the vibrational response observed, whereas the impact location was found to effect the frequency power ratios only, and not the resonant frequency values found. The presence of fracture was also found to have an effect on the overall vibrational response, however the impact energy was not found to have a significant effect.


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