Development and validation of a biofidelic head form model to assess blast-induced traumatic brain injury

Author(s):  
Devon Downes ◽  
Amal Bouamoul ◽  
Simon Ouellet ◽  
Manouchehr Nejad Ensan

Traumatic Blast Injury (TBI) associated with the human head is caused by exposure to a blast loading, resulting in decreased level of consciousness, skull fracture, lesions, or death. This paper presents the simulation of blast loading of a human head form from a free-field blast with the end goal of providing insight into how TBI develops in the human head. The developed numerical model contains all the major components of the human head, the skull, and brain, including the tentorium, cerebral falx, and gray and white matter. A nonlinear finite element analysis was employed to perform the simulation using the Arbitrary Lagrangian–Eulerian finite element method. The simulation captures the propagation of the blast wave through the air, its interaction with the skull, and its transition into the brain matter. The model quantifies the pressure histories of the blast wave from the explosive source to the overpressure on the skull and the intracranial pressure. This paper discusses the technical approach used to model the head, the outcome from the analysis, and the implication of the results on brain injury.

Author(s):  
Sunil Sutar ◽  
Shailesh Ganpule

Abstract Blast induced traumatic brain injury (bTBI) research is crucial in asymmetric warfare. The finite element analysis is an attractive option to simulate the blast wave interaction with the head. The popular blast simulation methods are ConWep based pure Lagrangian, Arbitrary-Lagrangian-Eulerian, and Coupling method. This study examines the accuracy and efficiency of ConWep and Coupling methods in predicting the biomechanical response of the head. The simplified cylindrical, spherical surrogates and biofidelic human head models are subjected to field-relevant blast loads using these methods. The reflected overpressures at the surface and pressures inside the brain from the head models are qualitatively and quantitatively evaluated against the available experiments. Both methods capture the overall trends of experiments. Our results suggest that the accuracy of the ConWep method is mainly governed by the radius of curvature of the surrogate head. For the relatively smaller radius of curvature, such as cylindrical or spherical head surrogate, ConWep does not accurately capture decay of reflected blast overpressures and brain pressures. For the larger radius of curvature, such as the biofidelic human head, the predictions from ConWep match reasonably well with the experiment. For all the head surrogates considered, the reflected overpressure-time histories predicted by the Coupling method match reasonably well with the experiment. Coupling method uniquely captures the shadowing and union of shock waves governed by the geometry driven flow dynamics around the head. Overall, these findings will assist the bTBI modeling community to judiciously select an objective-driven modeling methodology.


Author(s):  
G. Krishnaveni ◽  
D. Dominic Xavier ◽  
R. Sarathkumar ◽  
G. Kavitha ◽  
M. Senbagan

Because of increase in threat from militant groups and during war exposure to blast wave from improvised explosive devices, Traumatic Brain Injury (TBI), a signature injury is on rise worldwide. During blast, the biological system is exposed to a sudden blast over pressure which is several times higher than the ambient pressure causing the damage in the brain. The severity of TBI due to air blast may vary from brief change in mental status or consciousness (termed as mild) to extended period of unconsciousness or memory loss after injuries (termed as severe). The blast wave induced impact on head propagates as shock wave with the broad spectrum of frequencies and stress concentrations in the brain. The primary blast TBI is directly induced by pressure differentials across the skull/fluid/soft tissue interfaces and is further reinforced by the reflected stress waves within the cranial cavity, leading to stress concentrations in certain regions of the brain. In this paper, an attempt has been made to study the behaviour of a human brain model subjected to blast wave based on finite element model using LSDYNA code. The parts of a typical human head such as skull, scalp, CSF, brain are modelled using finite element with properties assumed based on available literature. The model is subjected to blast from frontal lobe, occipital lobe, temporal lobe of the brain. The interaction of the blast wave with the head and subsequent transformation of various forms of shock energy internally have been demonstrated in the human head model. The brain internal pressure levels and the shear stress distribution in the various lobes of the brain such as frontal, parietal, temporal and occipital are determined and presented.


Author(s):  
Kaveh Laksari ◽  
Mehdi Shafieian ◽  
Cristina Parenti ◽  
Kurosh Darvish

The aim of this study is to present two dimensional models of human head undergoing linear acceleration and impact using finite element analysis and validating the results with dynamic impact experiments. The experimental model consisted of a cylindrical gel as brain surrogate material undergoing 55G deceleration with slip boundary condition. Two FE models were developed and compared namely, Lagrangian and Arbitrary Lagrangian Eulerian (ALE). Parameters such as the logarithmic strain and void generated in the posterior region of the head were used to validate the results.


2011 ◽  
Vol 467-469 ◽  
pp. 339-344
Author(s):  
Na Li ◽  
Jian Xin Liu

Head and neck injuries are the most frequent severe injury resulting from traffic accidents. Neck injury mechanisms are difficult to study experimentally due to the variety of impact conditions involved, as well as ethical issues, such as the use of human cadavers and animals. Finite element analysis is a comprehensive computer aided mathematical method through which human head and neck impact tolerance can be investigated. Detailed cervical spine models are necessary to better understand cervical spine response to loading, improve our understanding of injury mechanisms, and specifically for predicting occupant response and injury in auto crash scenarios. The focus of this study was to develop a C1–C2 finite element model with optimized mechanical parameter. The most advanced material data available were then incorporated using appropriate nonlinear constitutive models to provide accurate predictions of response at physiological levels of loading. This optimization method was the first utilized in biomechanics understanding, the C1–C2 model forms the basis for the development of a full cervical spine model. Future studies will focus on tissue-level injury prediction and dynamic response.


2011 ◽  
Vol 2-3 ◽  
pp. 140-143
Author(s):  
Qing Feng Yang ◽  
Peng Wang ◽  
Yu Hong Wang ◽  
Kai Zhang

The resonance frequency of the cymbal transducer ranges from 2kHz to 40kHz and its effective electromechanical coupling factor is around 20%. Finite element analysis has been performed to ascertain how the transducer’s makeup affect the transducer’s performance parameters. Two-dimensional axisymmetric model of the cymbal transducer was founded by finite element software-ANSYS, the application of the element type was discussed and the FEM models were built up under the far field condition. Eight groups of cymbal transducers of resonance frequency around 3kHz with different structural dimensions were designed. It was better for choosing the cymbal transducer of the 8mm cavity coping diameter, 20.8mm cavity bottom diameter and 26.8mm piezoelectric ceramic wafer diameter than others for reducing distortion degree of the signal and improving communication turnover in the researched cymbal transducers. It was appropriate for choosing the cymbal transducer of the 8mm cavity coping diameter, 22.4mm cavity bottom diameter and 26.4mm piezoelectric ceramic wafer diameter in order to improve the free-field voltage sensitivity and transmission efficient.


2011 ◽  
Vol 82 ◽  
pp. 680-685
Author(s):  
Jerzy Malachowski ◽  
Tadeusz Niezgoda

The paper is based on non–linear finite element analysis of the blast wave effects on structures, caused by the detonation of explosive materials. Dynamic response of a structure with and without elastomeric layers subjected to the shock wave produced by the detonation of high explosive materials is presented in this paper. Coupled Euler and Lagrange formulation are used in the finite element analysis of such problems to accurately represent the detonation phenomenon. Research related to blast wave propagation is not only aimed at its effect on structures but also on developing new concepts of protective panels. The research carried out on various structures (such as multi–layer panels) has been performed to find out the most efficient protection against a detonation wave. Tests of multi-layer protective panels ability to absorb the explosion energy were also conducted under field conditions and confirmed in numerical studies. The application of structural protective layers made of elastomeric material significantly reduced the blast wave thanks to dissipation capabilities. Additionally, the shape effect of structural steel elements (streamlined profile) during the interaction process with a shock wave has been also confirmed.


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