Affiliations: Department of Mechanical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
Correspondence:
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Corresponding author: Yunhua Luo, Department of Mechanical Engineering, E2-327 Engineering and Information Technology Complex (EITC), 75A Chancellors Circle, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada. Tel.: (204) 474-6899; Fax: (204) 275-7507; E-mail: Yunhua.Luo@umanitoba.ca.
Abstract: Understanding how a helmet protects the head, especially the soft brain tissues, is the prerequisite for improving helmet design. Intracranial pressure and stresses/strains in the brain tissues are the direct indicators of traumatic brain injury and they can be used to measure helmet performance. In this study, the effects of helmet design parameters such as the helmet shell stiffness, liner compliance and thickness on the brain injury indicators were investigated by virtual impact tests. A finite element head model (FEHM) was first constructed from medical images; a personally-fitted helmet made of composite material and foam was virtually prototyped using geometric information extracted from the FEHM; a helmet-head finite element model was then assembled. Virtual impact tests were conducted using the resulting helmet-head model. The obtained results suggested that, if the helmet shell already has adequate strength to resist excessive deformation and fracture, further increasing shell stiffness and strength would not considerably reduce intracranial pressure and brain strains; to reach the maximum protection with the available materials, the key is to effectively use the second stage in the stress-strain history of the liner foam material.
Keywords: Closed-head injury, sport helmet, image-based finite element model, composite materials, liner foam, virtual impact test
