Pressure and shear responses in brain injury models

wbldb

Bradshaw, D. R. S.^1,2; Morfey, C. L.¹

Pressure and shear responses in brain injury models

Proceedings of the 17th International Technical Conference on the Enhanced Safety of Vehicles (ESV)

Affiliations

¹ISVR, University of Southampton, UK

²First Technology, USA
Abstract

Finite element (FE) models of the brain are regularly used to investigate brain injury mechanisms. Validation of these models against cadaver impacts is usually restricted to intracranial pressure data. However, the low shear modulus of neural tissue means that injurious strains result from shear deformations. We show that brain injury models that are validated for pressure alone can give a wide range of shear responses to the same impact.

Holbourn’s arguments on the harmlessness of pressure are extended by introducing separate wave equations for pressure and shear, derived from the Helmholtz vector decomposition. Two idealised models of traumatic brain injury are used to show that there is no one-to-one relation between pressure and shear in head impacts lasting a few milliseconds. The first is an analytical model of wave propagation in the brain under the action of local skull bending. The second is a strain-validated FE representation of the coronal plane of the human head under rotational acceleration.

As there is no one-to-one relation between dilatation and distortion in typical head impacts, it is not acceptable to validate FE models for pressure and then use them to predict injury.
Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/Esv/esv17/Proceed/00197.pdf

Cited Works (10)

Year	Entry
1977	Nahum AM, Smith R, Ward CC. Intracranial pressure dynamics during head impact. In: Proceedings of the 21st Stapp Car Crash Conference. October 19-21, 1977; New Orleans, LA. Warrendale, PA: Society of Automotive Engineers:339-366. SAE 770922.
1943	Holbourn AHS. Mechanics of head injuries. Lancet. October 9, 1943;242(6267):438-441.
1990	Meaney DF, Thibault LE. Physical model studies of cortical brain deformation in response to high strain rate inertial loading. In: Proceedings of the 1990 International IRCOBI Conference on the Biomechanics of Impact. September 12-14, 1990; Lyon, France.215-224.
1999	Bain AC, Meaney DF. Thresholds for mechanical injury to the in vivo white matter. In: Proceedings of the 43rd Stapp Car Crash Conference. October 25-27, 1999; San Diego, CA. Warrendale, PA: Society of Automotive Engineers:295-302. SAE 99SC19.
2001	Bradshaw DRS, Ivarsson J, Morfey CL, Viano DC. Simulation of acute subdural hematoma and diffuse axonal injury in coronal head impact. J Biomech. January 2001;34(1):85-94.
1945	Holbourn AHS. The mechanics of brain injuries. Br Med Bull. January 1945;3(6):147-149.
1976	McElhaney JH, Roberts VL, Hilyard JF. Handbook of Human Tolerance. Tokyo, Japan: Japan Automobile Research Institute (JARI) Inc; 1976.
2000	Ivarsson J, Viano DC, Lövsund P, Aldman B. Strain relief from the cerebral ventricles during head impact: experimental studies on natural protection of the brain. J Biomech. February 2000;33(2):181-189.
1990	Margulies SS, Thibault LE, Gennarelli TA. Physical model simulations of brain injury in the primate. J Biomech. 1990;23(8):823-836.
1992	Trosseille X, Tarriére C, Lavaste F, Guillon F, Domont A. Development of a F.E.M. of the human head according to a specific test protocol. In: Proceedings of the 36th Stapp Car Crash Conference. November 2-4, 1992; Seattle, WA. Warrendale, PA: Society of Automotive Engineers:235-253. SAE 922527.

Cited By (18)

Year	Entry
2013	Sahoo D, Deck C, Willinger R. Medical imaging data implementation into human FE head modelling and validation. In: Proceedings of the 2013 International IRCOBI Conference on the Biomechanics of Injury. September 11-13, 2013; Gothenburg, Sweden.563-575.
2014	Ren L, Baumgartner D, Davidsson J, Yang J, Willinger R. Effect of the inhomogeneous brain mechanical characteristic on dynamic responses of head under trauma. In: Proceedings of the 2014 International IRCOBI Conference on the Biomechanics of Injury. September 10-12, 2014; Berlin, Germany.93-105.
2002	Kleiven S, Hardy WN. Correlation of an FE model of the human head with local brain motion: consequences for injury prediction. Stapp Car Crash J. 2002;46:123-144. SAE 2002-22-0007.
2007	Kleiven S. Predictors for traumatic brain injuries evaluated through accident reconstructions. Stapp Car Crash J. 2007;51:81-114. SAE 2007-22-0003.
2010	Chafi MS, Karami G, Ziejewski M. Biomechanical assessment of brain dynamic responses due to blast pressure waves. Ann Biomed Eng. February 2010;38(2):490-504.
2006	Kleiven S. Evaluation of head injury criteria using a finite element model validated against experiments on localized brain motion, intracerebral acceleration, and intracranial pressure. Int J Crashworthiness. 2006;11(1):65-79.
2009	Ho J, Kleiven S. Can sulci protect the brain from traumatic injury? J Biomech. September 18, 2009;42(13):2074-2080.
2012	Post A, Hoshizaki B, Gilchrist MD. Finite element analysis of the effect of loading curve shape on brain injury predictors. J Biomech. February 23, 2012;45(4):679-683.
2012	Post A, Hoshizaki TB. Mechanisms of brain impact injuries and their prediction: a review. Trauma. October 2012;14(4):327-349.
2002	Ivarsson J. Physical Modeling of Brain and Head Kinematics [PhD thesis]. Götenburg, Sweden: Chalmers University of Technology; 2002.
2018	Tierney G. A Biomechanical Assessment of Direct and Inertial Head Loading in Rugby Union [PhD thesis]. Dublin, Ireland: Trinity College Dublin; 2018.
2014	Patton DA. The Biomechanical Determinants of Sports-Related Concussion: Finite Element Simulations of Unhelmeted Head Impacts to Evaluate Kinematic and Tissue-Level Predictors of Injury and Investigate the Design Implications for Soft-Shell Headgear [PhD thesis]. University of New South Wales; March 2014.
2013	Post A. The Influence of Dynamic Response Characteristics on Traumatic Brain Injury [PhD thesis]. University of Ottawa; 2013.
2014	Rousseau P. Analysis of Concussion Metrics of Real-World Concussive and Non-Injurious Elbow and Shoulder to Head Collisions in Ice Hockey [PhD thesis]. University of Ottawa; 2014.
2016	Kendall M. Comparison and Characterization of Different Concussive Brain Injury Events [PhD thesis]. University of Ottawa; 2016.
2019	Cournoyer J. Head Impact Severity Associated With Loss of Consciousness and Impact Seizures in Sport-Related Concussions [PhD thesis]. University of Ottawa; 2019.
2022	Murphy A. Comparing Equestrian Helmets With and Without Rotational Technology Using an Equestrian Concussive Specific Helmet Test Protocol [Master's thesis]. University of Ottawa; 2022.
2023	Lyu D. Investigation of Biomechanical Thresholds of Mild to Severe Brain Injury Using an Anisotropic Visco-Hyperelastic Finite Element Head Model: Model Development and Simulation of Impact Injury and Blast Injury [PhD thesis]. Detroit, MI: Wayne State University; August 2023.