Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Finite Element Modeling of the Human Head
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.ORCID iD: 0000-0003-0125-0784
2002 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The main objectives of the present thesis were to define the dimension of head injuries in Sweden over a longer period and to present a Finite Element (FE) model of the human head which can be used for preventive strategies in the future. The annual incidence of head injuries in Sweden between 1987 and 2000 was defined at over 22 000, cases most of which were mild head injuries. In contrast to traffic accidents, head injuriy due to fall was the most important etiology. Of special interest was that the number of hematoma cases has increased.

A detailed and parameterized FE model of the human head was developed and used to evaluate the effects of head size, brain size and impact directions. The maximal effective stresses in the brain increased more than a fourfold, from 3.6 kPa for the smallest head size to 16.3 kPa for the largest head size using the same acceleration impulse. The size dependence of the intracranial stresses associated with injury is not predicted by the Head Injury Criterion (HIC). Simulations with various brain sizes indicated that the increased risk of Subdural Hematoma (SDH) in elderly people may to a part be explained by the reduced brain size resulting in a larger relative motion between the skull and the brain with distension of bridging veins. The consequences of this increased relative motion due to brain atrophy cannot be predicted by existing injury criteria.

From studies of the influence of impact directions to the human head, the highest shear strain in the brain stem is found for a Superior-Inferior (SI) translational impulse, and in the corpus callosum for a lateral rotational impulse when imposing acceleration pulses corresponding to the same impact power. It was concluded that HIC is unable to predict consequences of a pure rotational impulse, while the Head Impact Power (HIP) criterion needs individual scaling coefficients for the different terms to account for differences in intracranial response due to a variation in load direction. It is also suggested that a further evaluation of synergic effects of the directional terms of the HIP is necessary to include combined terms and to improve the injuryprediction.

Comparison of the model with experiments on localized motion of the brain shows that the magnitude and characteristics of the deformation are highly sensitive to the shear properties of the brain tissue. The results suggest that significantly lower values of these properties of the human brain than utilized in most 3D FE models today must be used to be able to predict the localised brain response of an impact to the human head. There is a symmetry in the motion of the superior and inferior markers for both the model and the experiments following a sagittal and a coronal impact. This can possibly be explained by the nearly incompressible properties of brain tissue. Larger relative motion between the skull and the brain is more apparent for an occipital impact than for a frontal one in both experiments and FE model. This correlates with clinical findings. Moreover, smaller relative motion between the skull and the brain is more apparent for a lateral impact than for a frontal one for both experiments and FE model. This is thought to be due to the supporting structure of the falx cerebri.

Such a parametrized and detailed 3D model of the human head has not, to the best knowledge of the author, previously been developed. This 3D model is thought to be of significant value for looking into the effects of geometrical variations of the human head.

Place, publisher, year, edition, pages
Stockholm: KTH , 2002. , ix, 49 p.
Series
Report. Department of Aeronautics, 2002-9
Keyword [en]
Finite element method (FEM), Human head, brain, head injury, epidemiology, statistics, simulations.
Identifiers
URN: urn:nbn:se:kth:diva-3347OAI: oai:DiVA.org:kth-3347DiVA: diva2:9137
Public defence
2002-05-29, 00:00 (English)
Note
QC 20100428 NR 20140805Available from: 2002-05-22 Created: 2002-05-22 Last updated: 2010-04-28Bibliographically approved
List of papers
1. Influence of Impact Direction on the Human Head in Prediction of Subdural Hematoma
Open this publication in new window or tab >>Influence of Impact Direction on the Human Head in Prediction of Subdural Hematoma
2003 (English)In: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 20, no 4, 365-379 p.Article in journal (Refereed) Published
Abstract [en]

The objective of the present study was to analyze the effect of different loading directions following impact, and to evaluate existing global head injury criteria. Detailed and parameterized models of the adult human head were created by using the Finite Element Method (FEM). Loads corresponding to the same impact power were imposed in different directions. Furthermore, the Head Injury Criterion (HIC) and the recently proposed Head Impact Power (HIP) criterion were evaluated with respect to the relative motion between the skull and the brain, as well as the strain in the bridging veins. It was found that the influence of impact direction had a substantial effect on the intracranial response. The largest relative skull-brain motion and strain in the bridging veins occurred with the anterior-posterior (AP) and posterior-anterior (PA) rotational impulses. HIC was unable to predict consequences of a pure rotational impulse while HIP needed individual scaling coefficients for the different terms to account for difference in load direction. When using the proposed scaling procedure, a better prediction of subdural hematoma (SDH) was obtained. It is thus suggested that an evaluation of the synergistic terms is necessary to further improve the injury prediction. These variations should be considered when developing new head injury criteria.

Keyword
finite element method (FEM), head impact power (HIP), head injury, head injury criterion (HIC)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-12477 (URN)10.1089/089771503765172327 (DOI)000182609900006 ()
Note
QC 20100428Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2017-12-12Bibliographically approved
2. Correlation of an FE Model of the Human Head with Local Brain Motion: Consequences for Injury Prediction
Open this publication in new window or tab >>Correlation of an FE Model of the Human Head with Local Brain Motion: Consequences for Injury Prediction
2002 (English)In: Stapp Car Crash journal, ISSN 1532-8546, Vol. 46, 123-144 p.Article in journal (Refereed) Published
Abstract [en]

A parameterized, or scalable, finite element (FE) model of the human head was developed and validated against the available cadaver experiment data for three impact directions (frontal, occipital and lateral). The brain material properties were modeled using a hyperelastic and viscoelastic constitutive law. The interface between the skull and the brain was modeled in three different ways ranging from purely tied (no-slip) to sliding (free-slip). Two sliding contact definitions were compared with the tied condition. Also, three different stiffness parameters, encompassing the range of published brain tissue properties, were tested. The model using the tied contact definition correlated well with the experimental results for the coup and contrecoup pressures in a frontal impact while the sliding interface models did not. Relative motion between the skull and the brain in lowseverity impacts appears to be relatively insensitive to the contact definitions. It is shown that a range of shear stiffness properties for the brain can be used to model the pressure experiments, while relative motion is a more complex measure that is highly sensitive to the brain tissue properties. Smaller relative motion between the brain and skull results from lateral impact than from a frontal or occipital blow for both the experiments and FE simulations. The material properties of brain tissue are important to the characteristics of relative brain-skull motion. The results suggest that significantly lower values of the shear properties of the human brain than currently used in most three-dimensional (3D) FE models today are needed to predict the localized brain response of an impact to the human head.

Keyword
Finite element (FE) analysis, human head, brain displacement, intracranial pressure, brain material properties
National Category
Medical and Health Sciences Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-12478 (URN)17096222 (PubMedID)
Note
QC 20100428Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2011-02-11Bibliographically approved
3. The epidemiology of head injuries in Sweden from 1987 to 2000
Open this publication in new window or tab >>The epidemiology of head injuries in Sweden from 1987 to 2000
2003 (English)In: Injury control and safety promotion, ISSN 1566-0974, E-ISSN 1744-4985, Vol. 10, no 3, 173-180 p.Article in journal (Refereed) Published
Abstract [en]

The purpose of the present study was to evaluate the variability in the annual head injury incidence rate in Sweden from 1987 to 2000. It was hypothesized that the annual incidence rate would decrease over time due to a variety of primary preventive strategies that have been introduced in Swedish society. We used the Hospital Discharge Register at the National Board for Health and Welfare and head injury codes 800-804, and 850-854 from ICD9 system and S2.0-S2.9, and S6.0-S6.9 codes from ICD-10 system. We evaluated the patterns of age, gender, external cause of injury (E-code), type of injury, length of hospital stay, and trends over time. Head injuries due to transportation collision were reduced over the 14-year period analysis. Falls persisted as the dominant cause of head injury. Overall, men had 2.1 times the incidence of head injury compared to women. There was a decline in younger ages experiencing a head injury over this interval, while the number of head injuries among elderly people increased over time. Concussion was about three times more frequent than fractures. Hematoma and diffuse or focal contusions had a much lower incidence rate than concussion. Concussions and fractures decreased over time. Diffuse or focal injuries showed a steady rate of occurrence over the study interval while hematoma increased. Although length of hospital stay varied widely from zero to more than 50 days, 73.6% of hospital days were confined to two days or less. The incidence rate is stable over this time frame. While head injuries attributable to transportation accidents decreased, falls made up an increasing proportion of head injuries. Since we observed an increase in head injuries among elderly, primary prevention strategies may need to be targeted at this age group, and at preventing falls.

Keyword
adolescent, adult, aged, article, falling, female, head injury, human; incidence, length of stay, male, middle aged, statistics, Sweden, traffic accident
National Category
Engineering and Technology Medical and Health Sciences
Identifiers
urn:nbn:se:kth:diva-12473 (URN)12861916 (PubMedID)
Note
QC 20100429Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2017-12-12Bibliographically approved
4. Consequences of head size following trauma to the human head
Open this publication in new window or tab >>Consequences of head size following trauma to the human head
2002 (English)In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 35, no 2, 153-160 p.Article in journal (Refereed) Published
Abstract [en]

The objective of the present study was to evaluate whether variation of human head size results in different outcome regarding intracranial responses following a direct impact. Finite Element models representing different head sizes and with various element mesh densities were created. Frontal impacts towards padded surfaces as well as inertial loads were analyzed. The variation in intracranial stresses and intracranial pressures for different sizes of the geometry and for various element meshes were investigated. A significant correlation was found between experiment and simulation with regard to intracranial pressure characteristics. The maximal effective stresses in the brain increased more than a fourfold, from 3.6 kPa for the smallest head size to 16.3 kPa for the largest head size using the same acceleration impulse. When simulating a frontal impact towards a padding, the head injury criterion (HIC) value varies from the highest level of 2433 at a head mass of 2.34 kg to the lowest level of 1376 at a head mass of 5.98 kg, contradicting the increase in maximal intracranial stresses with head size. The conclusion is that the size dependence of the intracranial stresses associated with injury, is not predicted by the HIC. It is suggested that variations in head size should be considered when developing new head injury criteria.

Keyword
Human head, Impact, Finite element analysis, Parametrization
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-12474 (URN)10.1016/S0021-9290(01)00202-0 (DOI)000173610100001 ()
Note
QC 20100428Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2017-12-12Bibliographically approved
5. Consequences of Reduced Brain Volume Following Impact in Prediction of Subdural Hematoma Evaluated with Numerical Techniques
Open this publication in new window or tab >>Consequences of Reduced Brain Volume Following Impact in Prediction of Subdural Hematoma Evaluated with Numerical Techniques
2002 (English)In: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 3, no 4, 303-310 p.Article in journal (Refereed) Published
Abstract [en]

Detailed and parameterized models of the adult human head were created using the finite element method. Different sizes of the brain and the subdural space were generated, and the models were impacted toward padded surfaces in the frontal, temporal, and occipital direction. The present results show for the first time that, by reducing the brain size and thereby increasing the volume in the subdural space in the finite element model, a significant increase in relative motion was found between the skull and brain which correlated with the reduction of brain size.

Keyword
Atrophy; Brain; Finite Element Method; Head Impact Power; Head Injury Criterion; Subdural Hematoma
National Category
Engineering and Technology Medical and Health Sciences
Identifiers
urn:nbn:se:kth:diva-12479 (URN)10.1080/15389580214633 (DOI)
Note
QC 20100428Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2017-12-12Bibliographically approved

Open Access in DiVA

fulltext(2849 kB)8094 downloads
File information
File name FULLTEXT01.pdfFile size 2849 kBChecksum MD5
9c53763aecd88b208c772502caf6607f09e399b275b483520b413cfb229efccd3fdf2a53
Type fulltextMimetype application/pdf

Authority records BETA

Kleiven, Svein

Search in DiVA

By author/editor
Kleiven, Svein
By organisation
Aeronautical and Vehicle Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 8094 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 3828 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf