Generation of geometry of closed human head and discretisation for finite element analysis
01 May 1995-Medical & Biological Engineering & Computing (Med Biol Eng Comput)-Vol. 33, Iss: 3, pp 349-353
TL;DR: The experiment used four acid dyes, three basic dyes and two solvents, ethanol and toluene to create spots that cured under pressure, preventing bubbles appearing in the spots as a result of the contraction of the rubber during cure.
Abstract: The experiment used four acid dyes, three basic dyes and two solvents, ethanol and toluene. The procedure was to stir a very small quantity 1 mm 3) o f powdered dye into 2 ml of the selected solvent and then to mix this with 2 ml o f D e 3140. The mixture was deposited as 'spots,' about 1.5 cm in diameter, on to clean microscope slides, which were then cured in moist air in a pressure chamber at 2 bar. Curing under pressure prevents bubbles appearing in the spots as a result of the contraction of the rubber during cure. The spot colours noted were those seen after 24 h; in most cases, however, the colour developed within a few minutes and was stable therafter, 48 h were allowed for cure.
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TL;DR: The results indicate that, despite the fundamental differences between these six model formulations, the comparisons with the experimentally measured pressures and relative displacements were largely consistent and in good agreement and may prove useful for those attempting to model real life accident scenarios.
Abstract: In order to create a useful computational tool that will aid in the understanding and perhaps prevention of head injury, it is important to know the quantitative influence of the constitutive properties, geometry and model formulations of the intracranial contents upon the mechanics of a head impact event. The University College Dublin Brain Trauma Model (UCDBTM) [1] has been refined and validated against a series of cadaver tests and the influence of different model formulations has been investigated. In total six different model configurations were constructed: (i) the baseline model, (ii) a refined baseline model which explicitly differentiates between grey and white neural tissue, (iii) a model with three elements through the thickness of the cerebrospinal fluid (CSF) layer, (iv) a model simulating a sliding boundary, (v) a projection mesh model (which also distinguishes between neural tissue) and (vi) a morphed model. These models have been compared against cadaver tests of Trosseille [2] an...
216 citations
01 Jan 2000
TL;DR: In this paper, the authors defined the dimension of head injuries in Sweden over a longer period and presented a finite element (FE) model of the human head which can be used to diagnose head injuries.
Abstract: 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 ...
108 citations
TL;DR: In this article, the current status related to motorcycle helmet crash studies from biomechanics and computational point of view is reviewed, and the importance of motorcycle helmet performance on statistical background was reviewed.
52 citations
TL;DR: Three-dimensional finite-element analysis is carried out to investigate the influence of the partitioning membranes of the brain and the neck in head injury analysis through free-vibration analysis and transient analysis.
Abstract: A head injury model consisting of the skull, the CSF, the brain and its partitioning membranes and the neck region is simulated by considering its near actual geometry. Three-dimensional finite-element analysis is carried out to investigate the influence of the partitioning membranes of the brain and the neck in head injury analysis through free-vibration analysis and transient analysis. In free-vibration analysis, the first five modal frequencies are calculated, and in transient analysis intracranial pressure and maximum shear stress in the brain are determined for a given occipital impact load.
45 citations
TL;DR: Shear strain theory appears to better account for the clinical findings in head injury when the head is subjected to an indirect impact, and predictions of cavitation theory that a pressure gradient develops in the brain during indirect impact are supported.
Abstract: The mechanism of brain contusion has been investigated using a series of three-dimensional (3D) finite element analyses. A head injury model was used to simulate forward and backward rotation around the upper cervical vertebra. Intracranial pressure and shear stress responses were calculated and compared. The results obtained with this model support the predictions of cavitation theory that a pressure gradient develops in the brain during indirect impact. Contrecoup pressure-time histories in the parasagittal plane demonstrated that an indirect impact induced a smaller intracranial pressure (-53.7 kPa for backward rotation, and -65.5 kPa for forward rotation) than that caused by a direct impact. In addition, negative pressures induced by indirect impact to the head were not high enough to form cavitation bubbles, which can damage the brain tissue. Simulations predicted that a decrease in skull deformation had a large effect in reducing the intracranial pressure. However, the areas of high shear stress concentration were consistent with those of clinical observations. The findings of this study suggest that shear strain theory appears to better account for the clinical findings in head injury when the head is subjected to an indirect impact.
43 citations