Mechanisms of tensile failure of cerebrospinal fluid in blast traumatic brain injury
Author(s)
Yu, Xiancheng
Azor, Adriana
Sharp, David J
Mazdak, Ghajari
Type
Journal Article
Abstract
Mechanisms of blast-induced Traumatic Brain Injury (BTBI), particularly those linked to the primary pressure wave, are still not fully understood. One possible BTBI mechanism is cavitation in the cerebrospinal fluid (CSF) caused by CSF tensile failure, which is likely to increase strain and strain rate in the brain tissue near the CSF. Blast loading of the head can generate rarefaction (expansion) waves and rapid head motion, which both can produce tensile forces in the CSF. However, it is not clear which of these mechanisms is more likely to cause CSF tensile failure. In this study, we used a high-fidelity 3-dimensional computational model of the human head to test whether the CSF tensile failure increases brain deformation near the brain/CSF boundary and to determine the key failure mechanisms. We exposed the head model to a frontal blast wave and predicted strain and strain rate distribution in the cortex. We found that CSF tensile failure significantly increased strain and strain rate in the cortex. We then studied whether the rapid head motion or the rarefaction wave causes strain and strain rate concentration in cortex. We isolated these two effects by conducting simulations with pure head motion loading (i.e. prescribing the skull velocity but eliminating the pressure wave) and pure blast wave loading (i.e. eliminating head motion by fixing the skull base). Our results showed that the strain increase in the cortex was mainly caused by head motion. In contrast, strain rate increase was caused by both rapid head motion and rarefaction waves, but head motion had a stronger effect on elevating strain rate. Our results show that rapid motion of the head produced by blast wave is the key mechanism for CSF tensile failure and subsequent concentration of strain and strain rate in cortex. This finding suggests that mitigation of rapid head motion caused by blast loading needs to be addressed in the design of protective equipment in order to prevent the tensile failure of CSF.
Date Issued
2020-07
Date Acceptance
2020-04-12
Citation
Extreme Mechanics Letters, 2020, 38, pp.1-9
ISSN
2352-4316
Publisher
Elsevier BV
Start Page
1
End Page
9
Journal / Book Title
Extreme Mechanics Letters
Volume
38
Copyright Statement
© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
The Royal British Legion
National Institute for Health Research
UK DRI Ltd
Identifier
https://www.sciencedirect.com/science/article/pii/S2352431620300845?via%3Dihub
Grant Number
BMPF_P60304
NIHR-RP-011-048
'CR & T IMP'
Subjects
Science & Technology
Technology
Engineering, Mechanical
Materials Science, Multidisciplinary
Mechanics
Engineering
Materials Science
Blast injury
Traumatic brain injury
CSF tensile failure
Computational modelling
POSSIBLE DAMAGE MECHANISM
CAVITATION
SYSTEM
MODEL
Publication Status
Published
Article Number
100739
Date Publish Online
2020-04-18