Head Model for Protection - Computational Biomechanics of the Musculoskeletal System - page 245

19 Head Model for Protection
Lizhen Wang, Peng Xu, Xiaoyu Liu, Zhongjun Mo,
Ming Zhang, and Yubo Fan
ContentS
Summary ........................................................................................................................................ 245
19.1 Introduction .......................................................................................................................... 245
19.2 Development of a Finite Element Model of Human and Woodpecker Heads ......................246
19.2.1 Human and Woodpecker Head Anatomy .................................................................246
19.2.2 Geometry of the Model ............................................................................................ 247
19.2.3 Material Properties ................................................................................................... 248
19.2.4 Model Validation and Boundary Condition ............................................................. 248
19.3 Stress Distribution of the Skull and the Strain Rate of the Brain ........................................ 250
19.3.1 Stress Distribution of the Skull at the Selected Points ............................................. 250
19.3.2 Strain Rate of the Brain at the Selected Points ......................................................... 250
19.4 Summary and Applications of the Models ........................................................................... 251
Acknowledgments .......................................................................................................................... 253
References ...................................................................................................................................... 253
Summary
Head injury is a leading cause of morbidity and death in both industrialized and developing coun-
tries. It is estimated that brain injuries account for 15% of the burden of fatalities and disabilities,
and represent the leading cause of death in young adults. Brain injury may be caused by an impact
or a sudden change in the linear and/or angular velocity of the head. However, the woodpecker does
not experience any head injury at the high speed of 6-7 m/s with a deceleration of 1000 g when it
drums a tree trunk. It is still not known how woodpeckers protect their brain from impact injury. In
order to investigate this, finite element (FE) models of human and woodpecker heads were estab-
lished to study the dynamic intracranial responses based on micro-CT and CT images, respectively.
The mechanical properties in the woodpecker's head were investigated using a mechanical testing
system. It was shown that the macro/micro morphology of the cranial bone and beak can be recog-
nized as a major contributor to nonimpact injuries. This biomechanical analysis makes it possible
to visualize events during woodpecker pecking and may inspire new approaches to prevention and
treatment of human head injury.
19.1 IntroduCtIon
Head injury remains an acute problem in road transport safety, especially for pedestrians and
motorcyclists around the world (McIntosh, 2005; Martin et al., 2008). Considering the competitive
team sports at the 2004 Olympic Games, it was shown that 24% of all the injuries reported were head
injuries (Junge et al., 2006). According to the European Brain Injury Consortium (EBIC) survey, 51%
of head injuries were from car accidents or sports related to falling (Finfer and Cohen, 2001; Yang
et al., 2006). Holbourn (1943) was the first to cite angular acceleration as an important mechanism
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