Numerical modeling of primary thoracic traumabecause of blast

Since explosive blasts continue to cause casualties in both civil and military environments, there is a need for an understanding of the mechanisms of blast trauma at the human organ level, plus a more detailed predictive methodology. The primary goal of this research was to develop a finite element model capable of predicting primary blast injury to the lung so as to assist in the development of personal protective equipment. Numerical simulation of thorax blast loading consisted of the following components: 3D thorax modeling reconstruction, meshing and assembly of various thorax parts, blast and boundary loading, numerical solution, result extraction and data analysis. By comparing the models to published experimental data, local extent of injury in the lung was correlated to the peak pressure measured in each finite element, categorized as no injury [< 60 kPa], trace [60-100 kPa], slight [100-140 kPa], moderate [140-240 kPa] and severe [> 240 kPa]. It seemed that orienting the body at an angle of 45 degrees provides the lowest injury. The level and type of trauma inflicted on a human organ by a blast overpressure is related to many factors including: blast characteristics, body orientation, equipment worn and the number of exposures to blast loading

Finite element modeling of the human head under baton impact

This research will try to predict damage probability and calculate the main stress resulted from baton impacts by finite element [FE] modeling of the human head considering skull texture, brain and cerebrospinal fluid. A three dimensional FE model of the skull-brain complex was constructed for simulating the baton impact. The FE analysis was carried out using ANSYS program with a nonlinear transient dynamic procedure and the Euler-Lagrangian coupling method. The data used this study were taken from the literature, mentioned in Tables 2 and 3. Different results were carried out with different values of the bulk modulus and the short-term shear modulus [G[0]] for the cerebrospinal fluid and brain material. Considering the values from Figure 8, it was found that the short term shear modulus of the neural tissue had the biggest effect on intracranial frontal pressure and on the model's Von-Mises response. A comparison between different mesh densities showed that a coarsely meshed model is adequate for investigating the pressure response of the model, while a finer mesh is more appropriate for detailed investigations. Because of the complexity of this phenomenon, in spite of its importance, there is a little understanding of how baton impact affects the human head. In this paper, the model was validated against a series of cadaveric impact tests. We can conclude that a well validated FE modeling is a powerful tool for investigating the physical process of simulating head trauma.

Biomechanical analysis of blast-induced traumatic brain injury

Blast-induced traumatic brain injury [bTBI] is one of the causes of death or permanent invalidity which can occur unexpectedly in both military and civilian populations. This study set out to conduct a combined Eulerian-Lagrangian computational analysis of the interaction between a single planar blast wave and a human head in order to assess the extent of intracranial shock wave generation and its potential for causing traumatic brain injury. To investigate the mechanical response of human brain to blast waves and to identify the injury mechanisms of TBI, a three-dimensional finite elementhead model consisting of the scalp, skull, cerebrospinal fluid [CSF] and brain was developed from the imaging data of a human head.The mechanical properties of brain tissue were obtained from the literature. Throughout the loading regime, CSF acted as a protective layer for brain tissue by absorbing shear strain energy. Biomechanical loading of the brain was governed by direct wave transmission, structural deformations, and wave reflections from tissue-material interfaces. The brain experiences a complex set of direct and indirect loadings emanating from different sources [reflections from tissue interfaces and skull deformation] at different points of time. The flow dynamics strongly depend on geometry [shape, curvature] and structure [flexural rigidity, thickness] of a specimen and should be considered in understanding biomechanical loading pattern.