Download or read book Finite Element Analysis of Traumatic Brain Injury Due to Small Unmanned Aircraft System sUAS Impacts on the Human Head written by Alex Nelson Smith and published by . This book was released on 2019 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: A biofidelic finite element model was developed from an acquired set of CT scans for a range of human head and UAS impacts to provide simulations of multiple velocity scenarios of impact severity at four impact orientations on the human head. The hypothesis was that a correlation existed between the total amounts of kinetic energy of the impact from the UAS and human head collision, as well as that location of impact plays a role in the injury risk sustained. Linear acceleration, angular velocity, and pressure data values were calculated for each individual simulated case and then further correlated to injury risks that represent the severity of damage that would be sustained from the collision. Resulting data proved to show that impact kinetic energy, impact orientation, and impact response of the head and UAS all play vital roles in the amount of damage that is sustained from the impact collisions.
Download or read book Using Finite Element Modeling to Analyze Injury Thresholds of Traumatic Brain Injury from written by Anna Marie Dulaney and published by . This book was released on 2018 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: A finite element model was developed for a range of human head-sUAS impacts to provide multiple case scenarios of impact severity at two response regions of interest: global and local. The hypothesis was that for certain impact scenarios, local response injuries of the brain (frontal, parietal, occipital, temporal lobes, and cerebellum) have a higher severity level compared to global response injury, the response at the Center of Gravity (CG) of the head. This study is the first one to predict and quantify the influence of impact parameters such as impact velocity, location, offset, and angle of impact to severity of injury. The findings show that an sUAS has the potential of causing minimal harm under certain impact scenarios, while other scenarios cause fatal injuries. Additionally, results indicate that the human head’s global response as a less viable response region of interest when measuring injury severity for clinical diagnosis. It is hoped that the results from this research can be useful to assist decision making for treatments and may offer different perspectives in sUAS designs or operation environments.
Download or read book A Finite Element Head Injury Model Theory development and results written by T. A. Shugar and published by . This book was released on 1977 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite Element Modeling of Human Brain Response to Football Helmet Impacts written by Timothy Darling and published by . This book was released on 2014 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: The football helmet is a device used to help mitigate the occurrence of impact-related traumatic (TBI) and minor traumatic brain injuries (mTBI) in the game of American football. The current design methodology of using a hard shell with an energy absorbing liner may be adequate for minimizing TBI, however it has had less effect in minimizing mTBI. The latest research in brain injury mechanisms has established that the current design methodology has produced a helmet to reduce linear acceleration of the head. However, angular accelerations also have an adverse effect on the brain response, and must be investigated as a contributor of brain injury. To help better understand how the football helmet design features effect the brain response during impact, this research develops a validated football helmet model and couples it with a full LS-DYNA human body model developed by the Global Human Body Modeling Consortium (v4.1.1). The human body model is a conglomeration of several validated models of different sections of the body. Of particular interest for this research is the Wayne State University Head Injury Model for modeling the brain. These human body models were validated using a combination of cadaveric and animal studies. In this study, the football helmet was validated by laboratory testing using drop tests on the crown of the helmet. By coupling the two models into one finite element model, the brain response to impact loads caused by helmet design features can be investigated. In the present research, LS-DYNA is used to study a helmet crown impact with a rigid steel plate so as to obtain the strain-rate, strain, and stress experienced in the corpus callosum, midbrain, and brain stem as these anatomical regions are areas of concern with respect to mTBI.
Download or read book Sensitivity Analysis of a Finite Element Head Model to Skull Material Properties in the Study of Traumatic Brain Injury written by Hesam Moghaddam and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Traumatic brain injury (TBI) occurs as result of a sudden trauma to the brain due to impacts or the rapid movement of the head caused by falls, accidents, sports contacts, and physical assaults. TBI can lead to long-term cognitive, physical, and neurological impairments and hence should be prevented. While head kinematics can be experimentally estimated - to a good extent - using dummy heads, assessment of tissue responses of the brain in terms of the intracranial pressure, shear stresses, and strains is technically and morally challenging. Accordingly, due to complications of experimental tests, computational methods such as finite element analysis (FEA) have extensively been used in the last decade to study the injury mechanisms associated with TBI. However, the fidelity of these models is still a concern when conclusions are to be drawn based on numerical results. One major aspect of each computational work is the implementation of accurate material models which can mimic the real behavior of biological tissues. Skull protects the brain against injury by attenuating the transferred load to the intracranial space upon an impact to the head. Several material properties have been used for skull in the literature in the context of impact induced TBI. These studies have used a wide range of densities and Youngu2019s moduli for the skull; however, they have used different head models and loading conditions. Our study aims to investigate the sensitivity of a FE head model to skull material properties. To this end, North Dakota State University Finite Element Head Model (NDSUFEHM) was exposed to an identical impact using three different sets of material properties in terms of density and Youngu2019s modulustaken from the well-substantiated impact TBI studies. A frontal impact scenario was developed by impacting the head moving at 2.5 m/s against a rigid wall 45 degrees about its horizontal plane. Time histories of ICP and shear stress at the location of maximum value were recorded and compared for all three material properties sets. Our primary results predicted noticeable differences among pressure and shear responses both in terms of the peak values and their pattern. Our results suggested the need for a unique set of skull properties in order to improve the biofidelity of FE models.
Download or read book An Embedded Element Based Human Head Model to Investigate Axonal Injury written by Venkata Garimella and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Traumatic brain injury is a significant public health problem in the world. Axonal injury is a type of mechanism of traumatic brain injury primarily characterized by damage to the axons. Enhanced understanding of the axonal deformation during a mechanical impact may facilitate a better understanding of the short and long-term sequela. The objective of this dissertation is to develop, validate and employ a multiscale model of the axonal fiber tracts that simulates the white matter of the brain and can be used to investigate the evolution of axonal damage under injurious loading conditions. An axonal fiber tract consists of hundreds or thousands of axons aligned together, which can experience mechanical deformation under a non-physiological loading such as impact and blast loading. To model axonal injury, we developed a new embedded element based head model using an explicit description of the diffusion tensor magnetic resonance tractography. This approach enables us to resolve the complex mechanical response of the axonal fibers during injurious loading conditions. The most promising aspect of this modeling approach is the capability of modeling the fiber tracts explicitly in a traditional finite element head model. This model was validated against experimental results followed by an in-depth finite element analysis. Upon subjecting to impact and blast loading conditions, the model revealed some new insights into the evolution of the axonal injury. The model was subsequently improved in terms of anatomical resolution and material complexity. We have also made theoretical improvements to the embedded element technique and developed an open source finite element library in this direction. Finally, we examined the potential extension of this embedded element technique into a multiphysics domain such as electro-physics.
Download or read book A Finite Element Head Injury Model Volume I Theory Development and Results Final Report written by T. A. Shugar and published by . This book was released on 1977 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Head Injury Simulation in Road Traffic Accidents written by Fábio A. O. Fernandes and published by Springer. This book was released on 2018-04-27 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work the development of a new geometrically detailed finite element head model is presented. Special attention is given to sulci and gyri modelling, making this model more geometrically accurate than others currently available. The model was validated against experimental data from impact tests on cadavers, specifically intracranial pressure and brain motion. Its potential is shown in an accident reconstruction case with injury evaluation by effectively combining multibody kinematics and finite element methodology.
Download or read book Investigations of Modern day Head Injuries written by David Bradford Stark and published by . This book was released on 2019 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: While concussions are a mild brain injury with a large prevalence, drone, or UAS head impacts pose a risk for more traumatic head injuries but currently have a low prevalence. However, the rate of drone impacts is likely to increase as the industry is expanding at a rapid rate and benefits associated with drone use are driving new federal regulations which would allow for more widespread UAS flights over people. Before UAS flight over people is made legal, the risk of human injury due to UAS impacts must be quantified and understood. For this work, UAS head impacts were carried out on post-mortem human surrogates (PMHS) (i.e. cadavers) and the Hybrid III ATD. PMHS impacts were used to assess the likelihood of injury resulting from UAS impacts, while ATD tests were compared to matched PMHS data to assess how well the ATD replicates human response in this new impact scenario. The study’s main conclusions were that serious head injuries are possible as a result of UAS impacts and additional investigation is required to determine appropriate injury criteria for use in predicting the severity of head injuries in UAS impact cases. Additionally, the ATD response did not replicate that of the PMHS, specifically in angled or vertical impacts; thus, caution should be exercised when using the Hybrid III ATD to assess the risk of injury in UAS impact scenarios.
Download or read book Development of Rat Head Finite Element Model and Tissue Level Biomechanical Threshold for Traumatic Axonal Injury written by Runzhou Zhou and published by . This book was released on 2020 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The white matter tissues with highly aligned axonal fibers were modeled with transversely isotropic materials to simulate impact direction-dependent injury in the brain. The rat head/body model was validated against in vivo rodent dynamic cortical deformation, brain-skull displacement, and head impact acceleration experimental data. A series of FE parametric studies were conducted to identify various biomechanical factors contributing to the variability of injury severity observed among experiments and across different labs. The FE rat model simulated in vivo TAI in rat brains from closed-head impact acceleration experiments. The correlation of the local biomechanical parameter map with the severity and extent of axonal injury map at tissue levels was established. This improved our understanding of tissue-level injury mechanism for white matter injury. The tissue level thresholds for white matter injury was established by logistic regression analysis. The localized severe TAI in cerebral white matter (corpus callosum region) was best predicted by intracranial pressure (81 kPa) and maximum principal strain (0.26), while the white matter tracts in the brainstem (pyramidal tracts) were best predicted by localized maximum principal strain (0.18) response. The tissue level thresholds developed from this study can be directly translated to the FE human head model. This information will enhance the capability of the human head model in predicting brain injury.
Download or read book A 3D FEM COMPARATIVE STUDY ON THE IMPACT RESPONSE BETWEEN HUMAN HEAD AND NOCSAE HEAD DUE TO FREE FALL written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : We all enjoy sports be it watching or playing. Concussion is well known topic when it comes sports related injuries. However, concussion and brain injury is not exclusive to sports and outdoor activities. Sometimes, even the impact due to slip and fall at small heights can cause serious damage to the head and brain. This report studies the response generated in the human head model and the commercially use dummy NOCSAE headform due to drop from height of 2, 3, 4 and 5 feet. Earlier studies have related brain kinetics and head kinematics to concussion and traumatic brain injury (TBI). There are also studies that relate the linear and angular accelerations between different commercial dummy head models and the human head model, which were done experimentally. The main purpose of his study is to compare these parameters for the both models analytically using simulations. The linear velocity corresponding to each drop height were calculated and used as input data for the simulations. The impacts were simulated using RADIOSS solver in Hypermesh. Various parameters like contact force, linear acceleration and its components along each of the co-ordinate axes were extracted from the FE analysis. These values were utilized to calculate linear and angular acceleration for the entire models. These values were plotted against tolerance limits for various levels of brain injury. v It was observed that linear acceleration values for both the Human Head model and the dummy NOCSAE Headform confirm each other. Superior impact of the head was found most susceptible to traumatic brain injury followed by lateral impact when linear acceleration was considered as the criteria. The values of angular acceleration though did not represent glaring similarities between the two models, but there was a general trend of increase in angular acceleration with increase in drop height.
Download or read book Finite Element Modeling of Brain Injury for Performance Evaluation of Football Helmets written by Derek Wallin and published by . This book was released on 2018 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: Football helmets worn today are primarily designed to prevent skull fracture and irreversible brain injury. In that limited respect, today’s helmets are a success with the frequency of reported football-related skull fracture a rare occurrence. In recent decades, however, concussion, mild traumatic brain injury (mTBI), and chronic traumatic encephalopathy (CTE) are being reported with increasing incidence. Helmet manufacturing companies are limited in their performance analysis of helmets, with no standard helmet testing procedures incorporating anatomical data or physiological weaknesses of the brain. Finite Element Modeling of the brain has allowed for analysis of the mechanics of brain injury and can provide injury metrics based on simulated brain injury. In this study the background on current helmet testing procedures is provided as well as a finite element study of brain injury to determine helmet performance. In addition, this modeling will be used to identify what types of impacts are most dangerous.
Download or read book Impact Head Injury written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Aerospace Medical Panel. Specialists' Meeting and published by . This book was released on 1997 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Assessment of the Potential for Neck Injury Due to Padding of Aircraft Interior Walls for Head Impact Protection Final Report written by R. Armenia-Cope and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Biodynamical Response of the Human Head for Injury Analysis written by Danielle N. George and published by . This book was released on 2001-09-01 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to develop a finite element model of the human head and neck to investigate the biomechanics of head injury. The finite element model is a two-dimensional, plane strain representation of the cervical spine, skull, and major components of the brain including the cerebrum, cerebellum, brain stem, tentorium and the surrounding cerebral spinal fluid. The dynamic response of the model is validated by comparison with the results of human volunteer sled acceleration experiments conducted by Ewing et al. 10 . To validate the head model, one of the head impact experiments performed on cadavers by Nahum et al. 24, is simulated. The model responses are compared with the measured cadaveric test data in terms of head acceleration, and intracranial pressures measured at four locations including the coup and contrecoup sites. The validated model is used to demonstrate that the Head Injury Criterion (HIC), which is based on resultant translational acceleration of the center of gravity of the head, does not relate to the various mechanisms of brain injury and is therefore insufficient in predicting brain injury.
Download or read book Modeling of Human Brain Tissues and Head Injuries Induced by Blast and Ballistic Impact written by Sahil Kulkarni and published by . This book was released on 2014 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of body armor and combat helmets has reduced fatalities from explosions and ballistic attacks. However, frequent use of improvised explosive devices and continuing efforts to reduce the weight of each combat helmet have increased the risk of ballistic-impact and blast-induced traumatic brain injuries among soldiers. The objective of this dissertation research project is to develop predictive constitutive and computational models to be used in head injury diagnosis and to aid in the development of new combat helmets that can mitigate non-penetrating head injuries. A transversely isotropic visco-hyperelastic constitutive model is provided for soft tissues, which accounts for large deformations, high strain rates, and short-memory effects. The presented model is tested for a range of strain rates and for multiple loading scenarios based on available experimental data for porcine and human brain tissues. Using this constitutive relation, a finite element model of a helmet/head assembly is developed to study non-penetrating TBI. The effects of constitutive models and blast directions on finite elements simulations of blast induced TBI are investigated. Further, the effectiveness of combat helmets against non-penetrating TBI induced by blast and ballistic impacts is studied. Two types of combat helmets are considered: the advanced combat helmet (ACH) and the enhanced combat helmet (ECH). Spatial distributions and temporal variations of the intracranial pressure and stress components obtained in the simulations reveal significant differences in brain tissue responses to different constitutive models and blast directions. It is found that these combat helmets provide some level of protection against non-penetrating TBI and that the level of protection is higher for the ECH than the ACH. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151836
Download or read book Biomechanical Analysis of Traumatic Brain Injury by MRI based Finite Element Modeling written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
