scholarly journals A QCT-Based Nonsegmentation Finite Element Head Model for Studying Traumatic Brain Injury

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Zhaoyang Liang ◽  
Yunhua Luo
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Heterogeneous Material ◽  
Material Model ◽  
Anatomical Structure ◽  
Head Model ◽  
Experiment Data ◽  
Intracranial Pressures ◽  
Strain Stress ◽  
Finite Element Head Models

In the existing finite element head models (FEHMs) that are constructed from medical images, head tissues are usually segmented into a number of components according to the interior anatomical structure of the head. Each component is represented by a homogenous material model. There are a number of disadvantages in the segmentation-based finite element head models. Therefore, we developed a nonsegmentation finite element head model with pointwise-heterogeneous material properties and corroborated it by available experiment data. From the obtained results, it was found that although intracranial pressures predicted by the existing (piecewise-homogeneous) and the proposed (pointwise-heterogeneous) FEHM are very similar to each other, strain/stress levels in the head tissues are very different. The maximum peak strains/stresses predicted by the proposed FEHM are much higher than those by the existing FEHM, indicating that piecewise-homogeneous FEHM may have underestimated the stress/strain level induced by impact and thus may be inaccurate in predicting traumatic brain injuries.

Intracranial pressure–based validation and analysis of traumatic brain injury using a new three-dimensional finite element human head model

2019 ◽  
Vol 234 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Tanu Khanuja ◽  
Harikrishnan Narayanan Unni
Keyword(s):  
Finite Element ◽  
Brain Injury ◽  
Intracranial Pressure ◽  
Brain Injuries ◽  
Three Dimensional ◽  
Human Head ◽  
Von Mises Stress ◽  
Head Model ◽  
Injury Mechanisms ◽  
Von Mises

Traumatic brain injuries are life-threatening injuries that can lead to long-term incapacitation and death. Over the years, numerous finite element human head models have been developed to understand the injury mechanisms of traumatic brain injuries. Many of these models are erroneous and used ellipsoidal or spherical geometries to represent brain. This work is focused on the development of high-quality, comprehensive three-dimensional finite element human head model with accurate representation of cerebral sulci and gyri structures in order to study traumatic brain injury mechanisms. Present geometry, predicated on magnetic resonance imaging data consist of three rudimentary components, that is, skull, cerebrospinal fluid with the ventricular system, and the soft tissues comprising the cerebrum, cerebellum, and brain stem. The brain is modeled as a hyperviscoelastic material. Meshed model with 10 nodes modified tetrahedral type element (C3D10M) is validated against two cadaver-based impact experiments by comparing the intracranial pressures at different locations of the head. Our results indicate a better agreement with cadaver results, specifically for the case of frontal and parietal intracranial pressure values. Existing literature focuses mostly on intracranial pressure validation, while the effects of von Mises stress on brain injury are not analyzed in detail. In this work, a detailed interpretation of neurological damage resulting from impact injury is performed by analyzing von Mises stress and intracranial pressure distribution across numerous segments of the brain. A reasonably good correlation with experimental data signifies the robustness of the model for predicting injury mechanisms based on clinical predictions of injury tolerance criteria.

Investigation of Traumatic Brain Injuries Using the Next Generation of Simulated Injury Monitor (SIMon) Finite Element Head Model

2008 ◽  
Author(s):  
Erik G. Takhounts ◽  
Stephen A. Ridella ◽  
Vikas Hasija ◽  
Rabih E. Tannous ◽  
J. Quinn Campbell ◽  
...  
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Traumatic Brain Injuries ◽  
Head Model ◽  
Next Generation

scholarly journals Development of a Finite Element Head Model for the Study of Impact Head Injury

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Bin Yang ◽  
Kwong-Ming Tse ◽  
Ning Chen ◽  
Long-Bin Tan ◽  
Qing-Qian Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Current Knowledge ◽  
Human Head ◽  
Von Mises Stress ◽  
Head Model ◽  
Fe Model ◽  
Prediction And Prevention ◽  
Von Mises ◽  
The Brain

This study is aimed at developing a high quality, validated finite element (FE) human head model for traumatic brain injuries (TBI) prediction and prevention during vehicle collisions. The geometry of the FE model was based on computed tomography (CT) and magnetic resonance imaging (MRI) scans of a volunteer close to the anthropometry of a 50th percentile male. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue. The cerebrospinal fluid (CSF) was simulated explicitly as a hydrostatic fluid by using a surface-based fluid modeling method. The model was validated in the loading condition observed in frontal impact vehicle collision. These validations include the intracranial pressure (ICP), brain motion, impact force and intracranial acceleration response, maximum von Mises stress in the brain, and maximum principal stress in the skull. Overall results obtained in the validation indicated improved biofidelity relative to previous FE models, and the change in the maximum von Mises in the brain is mainly caused by the improvement of the CSF simulation. The model may be used for improving the current injury criteria of the brain and anthropometric test devices.

FINITE ELEMENT ANALYSIS OF THE HUMAN HEAD UNDER SIDE CAR CRASH IMPACTS AT DIFFERENT SPEEDS

2014 ◽  
Vol 14 (06) ◽  
pp. 1440002 ◽  
Author(s):  
XINGQIAO DENG ◽  
SHOU AN CHEN ◽  
R. PRABHU ◽  
YUANYUAN JIANG ◽  
Y. MAO ◽  
...  
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Head Injuries ◽  
Human Head ◽  
Side Impact ◽  
Von Mises Stress ◽  
Head Model ◽  
Car Crash ◽  
Von Mises ◽  
The Impact

Mechanical response of the human head under a side car crash impact is crucial for modeling traumatic brain injuries (TBI) or concussions. The current advances in computational methods and the finite element models of the human head provide a significant opportunity for biomechanical study of brain injuries; however, limited experimental data is available for delineating the injury relationship between the head injury criteria (HIC) and the tensile pressure or von Mises stress. In this research, we assess human head injuries in a side impact car crash using finite element (FE) simulations that quantify the tensile pressures and maximum strain profiles. In doing so, five FE analyses for the human head have been carried out to investigate the correlations between the HIC measured in the dummy model at different moving deformable barrier (MDB) velocities increasing from 10 mph to 30 mph in 5 mph increments and the pressure and von Mises stress of the skull, the skin, the cerebral spinal fluid (CSF) and the brain. The computational simulation results for the tensile pressures and von Mises stresses correlated well with the HIC15 and peak accelerations. Also a second-order polynomial seemed to fit the stress levels to the impact speeds and as such the presented method for using FE human head analysis could be used for reconstruction of head impacts in different side car crash conditions; furthermore, the head model would provide a tool for investigation of the cause and mechanisms of head injuries once the type and locations of injuries are quantified.

Development of a Human Head-Neck Computational Model for Assessing Blast Injury

2009 ◽  
Author(s):  
J. C. Roberts ◽  
E. E. Ward ◽  
T. P. Harrigan ◽  
T. M. Taylor ◽  
M. A. Annett ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Experimental Testing ◽  
Grid Point ◽  
Blast Loading ◽  
Human Head ◽  
Material Model ◽  
Element Model ◽  
Head Model ◽  
The Brain

A finite element model (FEM) of the human head attached to a Hybrid III FEM neck was developed to study the effects of blast loading on the brain. Simulations of blast loading to this Human Head Finite Element Model (HHFEM) were generated by creating a computational fluid dynamics (CFD) model of the HHFEM headform in a shock tube. Three different driver pressure loading conditions from experimental testing of the Human Surrogate Head Model (HSHM) were simulated by this model. The pressure time histories at each grid point of the CFD headform were used as inputs to the HHFEM. Brain/cerebral spinal fluid (CSF) and CSF/skull boundary conditions along with different brain material models were considered. The Kelvin-Maxwell material model and a low friction surface-to-surface interface were found to best replicate conditions seen in experimental testing of the HSHM. Deformations in the anterior and posterior locations of the brain varied from 0.5–0.9 mm and intracranial pressures at those locations were between 32 and 55 kPa.

Finite Element Modeling of Penetrating Traumatic Brain Injuries

2000 ◽  
Author(s):  
Frank A. Pintar ◽  
Srirangam Kumaresan ◽  
Brian Stemper ◽  
Narayan Yoganandan ◽  
Thomas A. Gennarelli
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Human Head ◽  
Gunshot Wounds ◽  
Element Model ◽  
Traumatic Brain Injuries ◽  
Head Model ◽  
Qualitative Comparison ◽  
Biomechanical Behavior ◽  
Deformation Stress

Abstract Recent advances in the treatment of penetrating gunshot wounds to the head have saved lives. These advances are largely reported using retrospective analysis of patients with recommendations for treatment. Biomechanical quantification of intracranial deformation/stress distribution associated with the type of weapon (e.g., projectile geometry) will advance clinical understanding of the mechanics of penetrating wounds. The present study was designed to delineate the biomechanical behavior of the human head under penetrating impact of two different projectile geometries using a nonlinear, three-dimensional finite element model. The human head model included the skull and brain. The qualitative comparison of the model output with each type of projectile during various time steps indicates that the deformation/stress progresses as the projectile penetrates the tissue. There is also a distinct difference in the patterns of displacement for each type of projectile. The present study is a first step in the study of the biomechanics of penetrating traumatic brain injuries.

scholarly journals Simulation of mTBI Utilizing White Matter Properties from MRE

2020 ◽  
Author(s):  
Amit Madhukar ◽  
Martin Ostoja-Starzewski
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
White Matter ◽  
Stress Wave ◽  
Peak Pressure ◽  
Material Model ◽  
Stress Wave Propagation ◽  
Head Model ◽  
Transient Stress ◽  
High Resolution Mri

We extend our high-resolution MRI-based Finite Element (FE) head model, previously presented and validated in [1–3], by considering the heterogeneities of the white matter structures captured through the use of Magnetic Resonance Elastography (MRE). This approach imparts more sophistication to our numerical model and yields results that more closely match experimental results. It is found that the peak pressure more closely matches the experiments as compared to the heterogeneous case. Qualitatively, we find differences in stress wave propagation near the corpus callosum and the corona radiata, which are stiffer on average than the global white matter. We are able to study the effects of these stiff structures on transient stress wave propagation within the cerebrum, something that cannot be done with a homogenized material model.

Delamination in the scoring and folding of paperboard

TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 61-66 ◽  
Author(s):  
DOEUNG D. CHOI ◽  
SERGIY A. LAVRYKOV ◽  
BANDARU V. RAMARAO
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Strain Analysis ◽  
Local Strain ◽  
Uniaxial Stress ◽  
Material Model ◽  
Element Model ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Strain Fields

Delamination between layers occurs during the creasing and subsequent folding of paperboard. Delamination is necessary to provide some stiffness properties, but excessive or uncontrolled delamination can weaken the fold, and therefore needs to be controlled. An understanding of the mechanics of delamination is predicated upon the availability of reliable and properly calibrated simulation tools to predict experimental observations. This paper describes a finite element simulation of paper mechanics applied to the scoring and folding of multi-ply carton board. Our goal was to provide an understanding of the mechanics of these operations and the proper models of elastic and plastic behavior of the material that enable us to simulate the deformation and delamination behavior. Our material model accounted for plasticity and sheet anisotropy in the in-plane and z-direction (ZD) dimensions. We used different ZD stress-strain curves during loading and unloading. Material parameters for in-plane deformation were obtained by fitting uniaxial stress-strain data to Ramberg-Osgood plasticity models and the ZD deformation was modeled using a modified power law. Two-dimensional strain fields resulting from loading board typical of a scoring operation were calculated. The strain field was symmetric in the initial stages, but increasing deformation led to asymmetry and heterogeneity. These regions were precursors to delamination and failure. Delamination of the layers occurred in regions of significant shear strain and resulted primarily from the development of large plastic strains. The model predictions were confirmed by experimental observation of the local strain fields using visual microscopy and linear image strain analysis. The finite element model predicted sheet delamination matching the patterns and effects that were observed in experiments.

Lifetime Prediction of Tires with Regard to Oxidative Aging5

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Superposition Principle ◽  
Accelerated Aging ◽  
Material Model ◽  
Aging Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Reaction Processes

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.

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