An Assessment of Primary Blast Injury in Human Brains: A Numerical Simulation

2007 ◽  
Author(s):  
Mahdi Sotudehchafi ◽  
Ghodrat Karami ◽  
Mariusz Ziejewski
Keyword(s):  
Numerical Simulation ◽  
Blast Wave ◽  
Human Head ◽  
Blast Injury ◽  
Element Formulation ◽  
Pressure Waves ◽  
Arbitrary Lagrangian Eulerian ◽  
Wave Interactions ◽  
Structure Interaction ◽  
Human Brains

Most blast-related injuries happen as a result of complex pressure waves generated by the explosion. In this paper, we model the explosion from detonation and examine the blast propagation in air using Arbitrary Lagrangian–Eulerian (ALE) finite element formulation. The results of the simulation agree well with those of physical data obtained from blast wave experiments. Such results set the circumstances necessary for an examination of brain injury exposed to such situations. Thus the model will be coupled with a Fluid/Structure Interaction (FSI) algorithm to implicitly examine the blast wave interactions with a human head and to study the creation of high regions of biomechanics pressure and stress gradients.

Numerical Simulation of Twin-Parachute Inflation Process for Aircraft Ejection Escape

2020 ◽  
Author(s):  
Liwu Wang ◽  
Mingzhang Tang ◽  
Sijun Zhang
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Model ◽  
Physical Models ◽  
The Other ◽  
Arbitrary Lagrangian Eulerian ◽  
Safe Distance ◽  
Structure Interaction ◽  
Parachute Inflation ◽  
Good Agreement

Abstract In order to study the safe distance between twin-parachute during their inflation process for fighter ejection escape, the fighter was equipped with two canopies and two seats, two types of parachute were used to numerically simulate their inflation process, respectively. One of them is C-9, the other a slot-parachute (S-P). Their physical models were built, then the meshes inside and around both parachutes were generated for fluid-structure interaction (FSI) simulation. The penalty function and the arbitrary Lagrangian-Eulerian (ALE) method were employed in the FSI simulation. To validate the numerical model for FSI simulation, at first the single parachute of the twin-parachute was used for the FSI simulation, the predicted inflation times for both types of parachute were compared with the experimental data. The computed results are in good agreement with experimental data. As a result, the inflation times were predicted with twin-parachute for both kinds of parachute. On the basis of the locations of ejected seats after the separation of seat and pilot, the initial locations and orientations of twin-parachute were also obtained. The numerical simulations for both kinds of parachute were performed by the FSI method, respectively. Our results illustrate that when the interval time for two seats ejected is greater than 0.25s, two pilots attached the twin-parachute are safe, and the twin-parachute would not interfere each other. Moreover, our results also indicate that the FSI simulation for twin-parachute inflation process is feasible for engineering applications and have a great potential for wide use.

Evaluation of Blast Simulation Methods for Modeling Blast Wave Interaction with Human Head

2021 ◽  
Author(s):  
Sunil Sutar ◽  
Shailesh Ganpule
Keyword(s):  
Blast Wave ◽  
Wave Interaction ◽  
Human Head ◽  
Coupling Method ◽  
Radius Of Curvature ◽  
Simulation Methods ◽  
Arbitrary Lagrangian Eulerian ◽  
Element Analysis ◽  
Modeling Methodology ◽  
Blast Wave Interaction

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.

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

2017 ◽  
Vol 15 (3) ◽  
pp. 257-267
Author(s):  
Devon Downes ◽  
Amal Bouamoul ◽  
Simon Ouellet ◽  
Manouchehr Nejad Ensan
Keyword(s):  
Finite Element ◽  
Brain Injury ◽  
Blast Wave ◽  
Skull Fracture ◽  
Free Field ◽  
Blast Loading ◽  
Human Head ◽  
Arbitrary Lagrangian Eulerian ◽  
Element Analysis ◽  
Head Form

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.

Relationship Between Blast Overpressure and Shell Thickness on the Fluid Pressure on a Cylinder Under Blast Loading

2013 ◽  
Author(s):  
Veera Selvan ◽  
Namas Chandra
Keyword(s):  
Numerical Simulation ◽  
Intracranial Pressure ◽  
Blast Wave ◽  
Shell Thickness ◽  
Fluid Pressure ◽  
Human Head ◽  
Two Dimensional ◽  
Blast Overpressure ◽  
Simulation Results ◽  
Mechanical Insult

The mechanics of blast wave-head interaction determines the magnitude of mechanical insult to the human head during a field explosion and subsequent brain injury. In this work, blast overpressure and shell thickness are related to fluid pressure based on experimental and computational methods. A fluid-filled cylinder is idealized as a two-dimensional analog of a skull-brain complex and is subjected to a Friedlander blast wave. Strain and pressure on the surface of the cylinder and pressure in the fluid (analogue of Intracranial pressure) are experimentally measured and compared with numerical simulation results. The validated numerical model shows that fluid pressure increases linearly with increase in reflected overpressures (ROP) for a given shell thickness. When the ROP is kept constant, fluid pressure increases linearly with the decrease in shell thickness. An equation is developed for predicting the fluid pressure for a given ROP and shell thickness.

scholarly journals Large-Amplitude Sloshing With Submerged Blocks

1990 ◽  
Vol 112 (1) ◽  
pp. 104-108 ◽  
Author(s):  
A. Huerta ◽  
W. K. Liu
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Nonlinear Behavior ◽  
Forced Vibrations ◽  
Element Formulation ◽  
Arbitrary Lagrangian Eulerian ◽  
Water Pool ◽  
Surface Motion ◽  
Structure Interaction ◽  
Interaction Problem

The computer simulation of forced vibrations induced on a water pool is presented in this paper. The complexity of the seismic fluid-structure interaction problem is accentuated by the large free surface motion. To overcome this difficulty, the arbitrary Lagrangian Eulerian (ALE) finite element formulation is employed. Moreover, the nonlinear behavior of the free surface motion is also taken into account. The results of the numerical simulation are compared with published experimental data and the effectiveness of the ALE algorithm is demonstrated.

Numerical Simulation of Vortex Shedding From Elongated Rectangular Cylinders in a Rectangular Channel

2010 ◽  
Author(s):  
Lifang Liu ◽  
Daogang Lu ◽  
Quanxing Li
Keyword(s):  
Numerical Simulation ◽  
Vortex Shedding ◽  
Rectangular Channel ◽  
Stream Line ◽  
Arbitrary Lagrangian Eulerian ◽  
Structure Interaction ◽  
Rectangular Cylinder ◽  
Simulation Results ◽  
Rectangular Cylinders ◽  
Plate Type

A two-dimensional code was developed to simulate vortex shedding characteristic and flow-structure interaction (FSI) of plate-type structures. In the code the physical component boundary fitted coordinate (PCBFC) was used to deal with the curve boundary. The arbitrary Lagrangian Eulerian (ALE) method was used to realize the grid movement. A barrier unit idea was adopted to deal with the boundary of fluid domain and solid domain in the code. The code was validated by comparing the numerical simulation results with experimental data. It was found that the vortex shedding phenomena in case of rectangular cylinder are strongly related to the length of the rectangular cylinder in the stream line.

Numerical Simulation of Fluid-Structure Interaction Relations between Skull and Brain Based on ALE and Overlapping Mesh Methods

2015 ◽  
Vol 713-715 ◽  
pp. 1782-1785
Author(s):  
Jing Xu Jin ◽  
Jun Yuan Zhang ◽  
Xue Wei Song ◽  
Hao Hu ◽  
Xiao Yan Sun
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Brain Injury ◽  
Relative Displacement ◽  
Numerical Results ◽  
Experimental Results ◽  
Head Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Structure Interaction ◽  
Interaction Relations

To simulate skull-CSF-brain interaction relations, a simple finite element head model is established, based on ALE (Arbitrary Lagrangian-Eulerian) and overlapping mesh methods. The responses of head under impact was simulated with this model. The numerical results are coincidence well with the experimental results conducted by Nahum et al. What’s more, it is found that the skull-brain relative displacement and brain injury may be predicted better with the ALE method.

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