Blast Wave Loading Pathways in Heterogeneous Material Systems–Experimental and Numerical Approaches

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Veera Selvan ◽  
Shailesh Ganpule ◽  
Nick Kleinschmit ◽  
Namas Chandra
Keyword(s):  
Brain Injury ◽  
Blast Wave ◽  
Injury Severity ◽  
Flexural Rigidity ◽  
Temporal Variations ◽  
Blast Waves ◽  
Cylinder Surface ◽  
Mechanical Pressure ◽  
Pressure Pulses ◽  
The Brain

Blast waves generated in the field explosions impinge on the head-brain complex and induce mechanical pressure pulses in the brain resulting in traumatic brain injury. Severity of the brain injury (mild to moderate to severe) is dependent upon the magnitude and duration of the pressure pulse, which in turn depends on the intensity and duration of the oncoming blast wave. A fluid-filled cylinder is idealized to represent the head-brain complex in its simplest form; the cylinder is experimentally subjected to an air blast of Friedlander type, and the temporal variations of cylinder surface pressures and strains and fluid pressures are measured. Based on these measured data and results from computational simulations, the mechanical loading pathways from the external blast to the pressure field in the fluid are identified; it is hypothesized that the net loading at a given material point in the fluid comprises direct transmissive loads and deflection-induced indirect loads. Parametric studies show that the acoustic impedance mismatches between the cylinder and the contained fluid as well as the flexural rigidity of the cylinder determine the shape/intensity of pressure pulses in the fluid.

scholarly journals In silico investigation of biomechanical response of a human subjected to primary blast

2021 ◽  
Author(s):  
Sunil Sutar ◽  
Shailesh Ganpule
Keyword(s):  
White Matter ◽  
Blast Wave ◽  
Rotational Motion ◽  
Blast Waves ◽  
Primary Blast ◽  
Body Model ◽  
The Past ◽  
Biomechanical Response ◽  
The Brain ◽  
Full Body

The response of the brain to the explosion induced primary blast waves is actively sought. Over the past decade, reasonable progress has been made in the fundamental understanding of bTBI using head surrogates and animal models. Yet, the current understanding of how blast waves interact with the human is in nascent stages, primarily due to lack of data in humans. The biomechanical response in human is critically required so that connection to the aforementioned bTBI models can be faithfully established. Here, using a detailed, full-body human model, we elucidate the biomechanical cascade of the brain under a primary blast. The input to the model is incident overpressure as achieved by specifying charge mass and standoff distance through ConWep. The full-body model allows to holistically probe short- (<5 ms) and long-term (200 ms) brain biomechanical responses. The full-body model has been extensively validated against impact loading in the past. In this work, we validate the head model against blast loading. We also incorporate structural anisotropy of the brain white matter. Blast wave human interaction is modeled using a conventional weapon modeling approach. We demonstrate that the blast wave transmission, linear and rotational motion of the head are dominant pathways for the biomechanical loading of the brain, and these loading paradigms generate distinct biomechanical fields within the brain. Blast transmission and linear motion of the head govern the volumetric response, whereas the rotational motion of the head governs the deviatoric response. We also observe that blast induced head rotation alone produces a diffuse injury pattern in white matter fiber tracts. Lastly, we find that the biomechanical response under blast is comparable to the impact event. These insights will augment laboratory and clinical investigations of bTBI and help devise better blast mitigation strategies.

Investigating Pressure Wave Impact on a Surrogate Head Model Using Numerical Simulation Techniques

2019 ◽  
Author(s):  
Rohan Banton ◽  
Thuvan Piehler ◽  
Nicole Zander ◽  
Richard Benjamin ◽  
Josh Duckworth ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Blast Wave ◽  
Military Personnel ◽  
Pressure Wave ◽  
Blast Waves ◽  
Head Model ◽  
Wave Impact ◽  
Simulation Techniques

Abstract There is an urgent need to understand the mechanism leading to mild traumatic brain injury (mTBI) resulting from blast wave impact to the head. The recent conflicts in Iraq and Afghanistan have heightened the awareness of head impact injuries to military personnel resulting from exposure to blast waves [1, 2]. A blast wave generated in air is a by-product of the detonation of an explosive [3]. To date the mechanism resulting in mTBI from primary blast insult is still unclear.

Does Subarachnoid Space Protect the Brain From Blast Waves and/or Blunt Impacts?

2015 ◽  
Author(s):  
Siavash Hashemi ◽  
Ali M. Sadegh
Keyword(s):  
Blast Wave ◽  
Cross Sections ◽  
Subarachnoid Space ◽  
3D Model ◽  
Blast Waves ◽  
Local Models ◽  
Different Types ◽  
Compressive Pressure ◽  
The Brain ◽  
Head Neck

The objectives of this study is to investigate the transduction of blast wave through the SAS region and the influence of SAS including different types of trabeculae in reducing the strain in the brain, when the head is subjected to a blast wave, and finally, comparing that to a none blast load such as blunt impacts or angular accelerations of the head during contact sports or accidents. This is accomplished through a series of Global/Local models of the head, neck and the brain. Specifically, a validated FE 3D model of the head and neck is subjected to a blast wave and the time dependent local compressive pressure gradient on the dura matter is calculated. Then through several detailed local FE models of the head, consisting Dura mater, Gray matter, Subarachnoid space having trabeculae and the CSF, the strains in the brain are calculated. In the local models different architecture and morphology of the trabeculae (rod shaped and the tree-shaped) are considered. The Global/Local models were analyzed using ABAQUS 6.12. In addition, the same procedure has been carried out for a velocity impact profile corresponding to 1.1 mph. The results revealed that the shape of the trabeculae would not affect the severity of loads transferring to the brain from shock waves in blast scenarios. Moreover, the interaction between the CSF and Tree-shaped trabeculae and rods with smaller cross sections, protect the brain better in impacts.

scholarly journals Multicenter assessment of the Brain Injury Guidelines and a proposal of guideline modifications

2020 ◽  
Vol 5 (1) ◽  
pp. e000483 ◽  
Author(s):  
Abid D Khan ◽  
Anna J Elseth ◽  
Jacqueline A Brosius ◽  
Eliza Moskowitz ◽  
Sean C Liebscher ◽  
...  
Keyword(s):  
Patient Safety ◽  
Brain Injury ◽  
Length Of Stay ◽  
Resource Utilization ◽  
Injury Severity ◽  
Improve Patient Safety ◽  
Hospital Length ◽  
Hospital Length Of Stay ◽  
Head Ct ◽  
The Brain

BackgroundThe Brain Injury Guidelines provide an algorithm fortreating patients with traumatic brain injury (TBI) and intracranial hemorrhage(ICH) that does not mandate hospital admission, repeat head CT, orneurosurgical consult for all patients. The purposes of this study are toreview the guidelines’ safety, to assess resource utilization, and to proposeguideline modifications that improve patient safety and widespreadreproducibility.MethodsA multi-institutional review of TBI patients was conducted. Patients with ICH on CT were classified as BIG 1, 2, or 3 based on the guidelines. BIG 3 patients were excluded. Variables collected included demographics, Injury Severity Score (ISS), hospital length of stay (LOS), intensive care unit LOS, number of head CTs, type of injury, progression of injury, and neurosurgical interventions performed.Results269 patients met inclusion criteria. 98 were classifiedas BIG 1 and 171 as BIG 2. The median length of stay (LOS) was 2 (2,4)days and the ICU LOS was 1 (0,2) days. Most patients had a neurosurgeryconsultation (95.9%) and all patients included had a repeat head CT. 370repeat head CT scans were performed, representing 1.38 repeat scans perpatient. 11.2% of BIG 1 and 11.1% of BIG 2 patients demonstratedworsening on repeat head CT. Patients who progressed exhibited a higherISS (14 vs. 10, p=0.040), and had a longer length of stay (4 vs. 2 days;p=0.015). After adjusting for other variables, the presence of epiduralhematoma (EDH) and intraparenchymal hematoma were independent predictors ofprogression. Two BIG 2 patients with EDH had clinical deteriorationrequiring intervention.DiscussionThe Brain Injury Guidelines may improve resourceallocation if utilized, but alterations are required to ensure patientsafety. The modified Brain Injury Guidelines refine the originalguidelines to enhance reproducibility and patient safety while continuing toprovide improved resource utilization in TBI management.

Mechanical Response of the Brain Under Blast: The Effect of Blast Direction and the Head Protection

2016 ◽  
Author(s):  
Hesam Sarvghad-Moghaddam ◽  
Asghar Rezaei ◽  
Ashkan Eslaminejad ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Brain Injury ◽  
Mechanical Response ◽  
Experimental Studies ◽  
Human Head ◽  
Blast Waves ◽  
Arbitrary Lagrangian Eulerian ◽  
Explosion Pressure ◽  
Head Protection ◽  
Coupling Algorithm ◽  
The Brain

Blast-induced traumatic brain injury (bTBI), is defined as a type of acquired brain injury that occurs upon the interaction of the human head with blast-generated high-pressure shockwaves. Lack of experimental studies due to moral issues, have motivated the researchers to employ computational methods to study the bTBI mechanisms. Accordingly, a nonlinear finite element (FE) analysis was employed to study the interaction of both unprotected and protected head models with explosion pressure waves. The head was exposed to the incoming shockwaves from front, back, and side directions. The main goal was to examine the effects of head protection tools and the direction of blast waves on the tissue and kinematical responses of the brain. Generation, propagation, and interactions of blast waves with the head were modeled using an arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The FE simulations were performed using Ls-Dyna, a transient, nonlinear FE code. Side blast predicted the highest mechanical responses for the brain. Moreover, the protection assemblies showed to significantly alter the blast flow mechanics. Use of faceshield was also observed to be highly effective in the front blast due to hindering of shockwaves.

scholarly journals Correlation of Cerebral and Subcutaneous Glycerol in Severe Traumatic Brain Injury and Association with Tissue Damage

2021 ◽  
Author(s):  
Linda Hägglund ◽  
Magnus Olivecrona ◽  
Lars-Owe D. Koskinen
Keyword(s):  
Computed Tomography ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Injury Severity Score ◽  
Severe Traumatic Brain Injury ◽  
Tissue Damage ◽  
Injury Severity ◽  
Health Evaluation ◽  
Brain Tissue Damage ◽  
The Brain

Abstract Background This study is a substudy of a prospective consecutive double-blinded randomized study on the effect of prostacyclin in severe traumatic brain injury (sTBI). The aims of the present study were to investigate whether there was a correlation between brain and subcutaneous glycerol levels and whether the ratio of interstitial glycerol in the brain and subcutaneous tissue (glycerolbrain/sc) was associated with tissue damage in the brain, measured by using the Rotterdam score, S-100B, neuron-specific enolase (NSE), the Injury Severity Score (ISS), the Acute Physiology and Chronic Health Evaluation Score (APACHE II), and trauma type. A potential association with clinical outcome was explored. Methods Patients with sTBI aged 15–70 years presenting with a Glasgow Coma Scale Score ≤ 8 were included. Brain and subcutaneous adipose tissue glycerol levels were measured through microdialysis in 48 patients, of whom 42 had complete data for analysis. Brain tissue damage was also evaluated by using the Rotterdam classification of brain computed tomography scans and the biochemical biomarkers S-100B and NSE. Results In 60% of the patients, a positive relationship in glycerolbrain/sc was observed. Patients with a positive correlation of glycerolbrain/sc had slightly higher brain glycerol levels compared with the group with a negative correlation. There was no significant association between the computed tomography Rotterdam score and glycerolbrain/sc. S-100B and NSE were associated with the profile of glycerolbrain/sc. Our results cannot be explained by the general severity of the trauma as measured by using the Injury Severity Score or Acute Physiology and Chronic Health Evaluation Score. Conclusions We have shown that peripheral glycerol may flux into the brain. This effect is associated with worse brain tissue damage. This flux complicates the interpretation of brain interstitial glycerol levels. We remind the clinicians that a damaged blood–brain barrier, as seen in sTBI, may alter the concentrations of various substances, including glycerol in the brain. Awareness of this is important in the interpretation of the data bedside as well in research.

scholarly journals Transcriptional Pathology Evolves Over Time in Rat Hippocampus Following Lateral Fluid Percussion Traumatic Brain Injury

2021 ◽  
Author(s):  
Rinaldo Catta-Preta ◽  
Iva Zdillar ◽  
Bradley Jenner ◽  
Emily T. Doisy ◽  
Kayleen Tercovich ◽  
...  
Keyword(s):  
Gene Expression ◽  
Traumatic Brain Injury ◽  
Cell Death ◽  
Brain Injury ◽  
Injury Severity ◽  
Cholesterol Metabolism ◽  
Fluid Percussion ◽  
Differential Gene ◽  
Lateral Fluid Percussion ◽  
The Brain

Traumatic brain injury (TBI) causes acute and lasting impacts on the brain, driving pathology along anatomical, cellular, and behavioral dimensions. Rodent models offer the opportunity to study TBI in a controlled setting, and enable analysis of the temporal progression that occurs from injury to recovery. We applied transcriptomic and epigenomic analysis, characterize gene expression and in ipsilateral hippocampus at 1 and 14 days following moderate lateral fluid percussion (LFP) injury. This approach enabled us to identify differential gene expression (DEG) modules with distinct expression trajectories across the two time points. The major DEG modules represented genes that were up- or downregulated acutely, but largely recovered by 14 days. As expected, DEG modules with acute upregulation were associated with cell death and astrocytosis. Interestingly, acutely downregulated DEGs related to neurotransmission mostly recovered by two weeks. Upregulated DEG modules related to inflammation were not necessarily elevated acutely, but were strongly upregulated after two weeks. We identified a smaller DEG module with delayed upregulation at 14 days including genes related to cholesterol metabolism and amyloid beta clearance. Finally, differential expression was paralleled by changes in H3K4me3 at the promoters of differentially expressed genes at one day following TBI. Following TBI, changes in cell viability, function and ultimately behavior are dynamic processes. Our results show how transcriptomics in the preclinical setting has the potential to identify biomarkers for injury severity and/or recovery, to identify potential therapeutic targets, and, in the future, to evaluate efficacy of an intervention beyond measures of cell death or spatial learning.

Simulation of Blast Induced Traumatic Brain Injury using Finite Element Method

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
G. Krishnaveni ◽  
D. Dominic Xavier ◽  
R. Sarathkumar ◽  
G. Kavitha ◽  
M. Senbagan
Keyword(s):  
Traumatic Brain Injury ◽  
Finite Element ◽  
Brain Injury ◽  
Blast Wave ◽  
Ambient Pressure ◽  
Memory Loss ◽  
Human Head ◽  
Head Model ◽  
Stress Concentrations ◽  
The Brain

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.

Computational Analysis for Validation of Blast Induced Traumatic Brain Injury and Protection of Combat Helmet

2018 ◽  
Author(s):  
X. Gary Tan ◽  
Amit Bagchi
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Shock Tube ◽  
Blast Wave ◽  
High Fidelity ◽  
Blast Loads ◽  
Next Generation ◽  
Energy Transmission ◽  
The Brain

Current understanding of blast wave transmission and mechanism of primary traumatic brain injury (TBI) and the role of helmet is incomplete thus limiting the development of protection and therapeutic measures. Combat helmets are usually designed based on costly and time consuming laboratory tests, firing range, and forensic data. Until now advanced medical imaging and computational modeling tools have not been adequately utilized in the design and optimization of combat helmets. The goal of this work is to develop high fidelity computational tools, representative virtual human head and combat helmet models that could help in the design of next generation helmets with improved blast and ballistic protection. We explore different helmet configurations to investigate blast induced brain biomechanics and understand the protection role of helmet by utilizing an integrated experimental and computational method. By employing the coupled Eulerian-Lagrangian fluid structure interaction (FSI) approach we solved the dynamic problem of helmet and head under the blast exposure. Experimental shock tube tests of the head surrogate provide benchmark quality data and were used for the validation of computational models. The full-scale computational NRL head-neck model with a combat helmet provides physical quantities such as acceleration, pressure, strain, and energy to blast loads thus provides a more complete understanding of the conditions that may contribute to TBI. This paper discusses possible pathways of blast energy transmission to the brain and the effectiveness of helmet systems at blast loads. The existing high-fidelity image-based finite element (FE) head model was applied to investigate the influence of helmet configuration, suspension pads, and shell material stiffness. The two-phase flow model was developed to simulate the helium-air shock wave interaction with the helmeted head in the shock tube. The main contribution was the elucidation of blast wave brain injury pathways, including wave focusing in ocular cavities and the back of head under the helmet, the effect of neck, and the frequency spectrum entering the brain through the helmet and head. The suspension material was seen to significantly affect the ICP results and energy transmission. These findings can be used to design next generation helmets including helmet shape, suspension system, and eye protection.

scholarly journals Pathomorphological markers of blast-induced brain injury

Morphologia ◽  
2021 ◽  
Vol 15 (3) ◽  
pp. 96-100
Author(s):  
S.V. Kozlov ◽  
V.D. Mishalov ◽  
K.М. Sulojev ◽  
Yu.V. Kozlova
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Blast Wave ◽  
Age Distribution ◽  
Vascular Wall ◽  
Histopathological Analysis ◽  
Perivascular Spaces ◽  
Distribution Analysis ◽  
The Dead ◽  
The Brain

Background. Recently, interest in blast-induced brain injuries has been increasing due to military events and the use of explosive devices in eastern Ukraine. Considering the diagnostic uncertainty regarding the specific signs of brain injury after the distant action of an blast shock wave, the danger of prognostic consequences, the increase of the cases of explosive injury number, we consider that selected for study topic is relevant. Objective. Purpose – determination of pathomorphological changes of the brain after the action of the blast wave. Methods. To solving this purpose, a retrospective analysis of 280 cases of fatal military blast injuries was conducted. We selected 6 cases for microscopic examination of the brain. For histological examination, samples were taken from different parts of the brain. Results. Analysis of 280 deaths due to explosive trauma showed that 58.9% of the dead (165) had a traumatic brain injury, and in 131 cases it was accompanied by fractures of the bones of the vault and the base of the skull. Isolated traumatic brain injury was detected in only 33 cases (11.8%). Age distribution analysis of the dead people showed that 67.5% of the dead were between the ages of 21 and 40. Histopathological analysis of brain samples from the dead allowed to identify the characteristic signs of blast-induced brain injury in the form of diffuse formation of perivascular microhemorrhages with partial or complete separation of the vascular wall from the neuropil. Conclusion. The complex of microscopic signs in the brain, namely, the separation of vascular wall from neuroglia with the formation of perivascular space, fragmentation of these vessels walls, erythrocytes hemolysis, hemorrhage in the newly formed perivascular spaces, are direct evidences of the blast wave action.

Sign in / Sign up

Export Citation Format

Share Document