scholarly journals Characterization of Closed Head Impact Injury in Rat

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yi Hua ◽  
Praveen Akula ◽  
Matthew Kelso ◽  
Linxia Gu
Keyword(s):  
Injury Severity ◽  
Three Dimensional ◽  
Head Impact ◽  
Head Model ◽  
Lateral Impact ◽  
Factors Affecting ◽  
Closed Head ◽  
Impact Parameters ◽  
Three Dimensional Finite Element ◽  
The Impact

The closed head impact (CHI) rat models are commonly used for studying the traumatic brain injury. The impact parameters vary considerably among different laboratories, making the comparison of research findings difficult. In this work, numerical CHI experiments were conducted to investigate the sensitivities of intracranial responses to various impact parameters (e.g., impact depth, velocity, and position; impactor diameter, material, and shape). A three-dimensional finite element rat head model with anatomical details was subjected to impact loadings. Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses. The influence of impactor diameter was region-specific and an increase in impactor diameter could substantially increase tissue strains in the region which located directly beneath the impactor. The lateral impact could induce higher strains in the brain than the central impact. An indentation depth instead of impact depth would be appropriate to characterize the influence of a large deformed rubber impactor. The experimentally observed velocity-dependent injury severity could be attributed to the “overshoot” phenomenon. This work could be used to better design or compare CHI experiments.

Optimization of the Engine Hood to Reduce the Head Injury during the Vehicle-Human Collision

2012 ◽  
Vol 192 ◽  
pp. 29-36
Author(s):  
Yu Xin Wang ◽  
Qing Chun Wang ◽  
Jian Rong Fu ◽  
Hong Hai Qiao
Keyword(s):  
Finite Element ◽  
Head Injury ◽  
Optimization Design ◽  
Three Dimensional ◽  
Element Model ◽  
Head Model ◽  
Modeling Software ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact

Effect of hard point of the engine hood on the head injury during the vehicle-human collision was studied to improve the design of engine hood. Firstly, the current common model of the engine hood was established with three-dimensional finite element modeling software, and 20 areas were divided, also a standard head finite element model was imported, secondly, each area of the engine hood was clashed by the standard head model, then the impact on the head injure was analyzed and the hard point of the hood area was achieved, thirdly, the optimization of the inside and outside panel materials and the plate structure were carried out to reduce the head damage. The simulation results show that the engine hood after optimization gave less damage to the head, which means the research carried out here is of a good reference to the engine hood optimization design for human protection

Numerical Analysis of the Biomechanical Characteristics and Impact Response of the Human Chest

2004 ◽  
Author(s):  
Hideyuki Kimpara ◽  
Masami Iwamoto ◽  
Isao Watanabe ◽  
Kazuo Miki ◽  
Jong B. Lee ◽  
...  
Keyword(s):  
Mass Density ◽  
Three Dimensional ◽  
Rib Fractures ◽  
Human Model ◽  
Fe Model ◽  
Lateral Impact ◽  
Internal Organs ◽  
Fractured Ribs ◽  
Three Dimensional Finite Element ◽  
The Impact

The mass density, Young’s modulus (E), tangent modulus (Et) and yield stress (σy) of the human ribs, sternum, internal organs and muscles play important roles when determining impact responses of the chest associated with pendulum impact. A series of parametric studies was conducted using a commercially available three-dimensional finite element (FE) model, Total HUman Model for Safety (THUMS) of the whole human body, to determine the effect of changing these material properties on the impact force, chest deflection, and the number of rib fractures and fractured ribs. Results from this parametric study indicate that the initial chest stiffness was mainly influenced by the mass density of the muscles covering the torso. The number of rib fractures and fractured ribs were primarily determined by E, Et and σy of the ribcage and sternum. Similarly, the E, Et and σy of the ribcage, which is defined as the bony skeleton of the chest, and sternum and E of the internal organs contributed to the maximum chest deflection in frontal impact, while the maximum chest deflection for lateral impact was mainly affected by the E, Et and σy of the ribcage.

Finite Element Analysis of Brain Damage due to Impact Force with a Three Dimensional Head Model

2005 ◽  
Vol 297-300 ◽  
pp. 1333-1338
Author(s):  
Chang Min Suh ◽  
Sung Ho Kim ◽  
Byung Won Hwang
Keyword(s):  
Finite Element ◽  
Brain Damage ◽  
Fe Simulation ◽  
Impact Force ◽  
Three Dimensional ◽  
Head Impact ◽  
Head Model ◽  
Fe Model ◽  
The Impact ◽  
The Brain

Brain damage by the impact force was evaluated by the numerical analysis with a three dimensional Finite Element (FE) model. The FE model was constructed from the MRI data of a subject, and visco-elastic behavior for constitutive equation was applied to the brain tissue. From the FE simulation, brain damage and deformation of the frontal head impacted by a steel impactor were analyzed. The variations of head acceleration and Intra-Cranial Pressure (ICP) during the impact were analyzed in order to evaluate Traumatic Brain Injury (TBI). In addition, relative displacement between the skull and the brain due to head impact was investigated. And, pathological severity was evaluated according to Head Injury Criterion (HIC) from the FE simulation. The analytic results of brain damage showed a good agreement with those of the cadaver test performed by Nahum et al. (1977) and other medical reports. And then, the variation of the HIC value was evaluated according to various impact conditions. This study would provide useful data and methodology in the field of biomechanics for analyzing the brain damage by head impact.

Nonlinear FEA Simulation of Thorax Considering Transient CPR and Lateral Forces

2012 ◽  
Author(s):  
Omar Awad ◽  
Yahia M. Al-Smadi
Keyword(s):  
Impact Load ◽  
Three Dimensional ◽  
Element Model ◽  
Lateral Force ◽  
The Body ◽  
Biomechanical Analysis ◽  
Lateral Impact ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact

Boxing or martial arts are games where players chests are subject to lateral impact, the impact loads travel through skin, ribs, mediastinum (i.e. a thoracic compartment) and then through the skeleton to the rest of the body. When thorax is subject to lateral force exceeding the elastic limit of thoracic compartment, players often go in shock demanding prompt resuscitation. This paper investigates the thorax response of boxer being subject to lateral impact followed by Cardiopulmonary resuscitation (CPR). Due to complexity of thorax structure and materials, three dimensional finite element model in ANSYS was created to perform the computational biomechanical analysis of two-stage loading (i.e. lateral impact load and CPR forces). Model input parameters such as material, loading and boundary conditions have been defined. Post processing values such as deformations and stresses have been presented.

Study on the critical loosening condition toward a new design guideline for bolted joints

2018 ◽  
Vol 233 (9) ◽  
pp. 3302-3316 ◽  
Author(s):  
Hao Gong ◽  
Jianhua Liu ◽  
Xiaoyu Ding
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Simulation Method ◽  
Bolted Joints ◽  
Design Guideline ◽  
Factors Affecting ◽  
Dimensional Finite Element ◽  
Frictional Coefficients ◽  
Three Dimensional Finite Element ◽  
Fit Tolerance

An understanding of conditions that trigger the loosening of bolted joints is essential to ensure joint reliability. In this study, a three-dimensional finite element model of a typical bolted joint is developed, and a new simulation method is proposed to quantitatively identify the critical transverse force for initiating loosening. This force is used to evaluate the anti-loosening capacity of bolted joints. Using the proposed simulation method, the effects of factors affecting critical loosening are systematically studied. It is found that the preload, frictional coefficients at the thread and the bearing surfaces, clamped length, and fit tolerance mainly affected loosening. When the preload and friction coefficients are increased, and the clamped length and fit tolerance are reduced, loosening is inhibited. Experiments are performed to demonstrate the reliability of the results. Finally, a suggestion is proposed to improve the design guideline VDI 2230 for bolted joints, which considers the requirement of avoiding loosening under vibrational loading.

Recognising Facial Surfaces

Perception ◽  
1991 ◽  
Vol 20 (6) ◽  
pp. 755-769 ◽  
Author(s):  
Vicki Bruce ◽  
Patrick Healey ◽  
Mike Burton ◽  
Tony Doyle ◽  
Anne Coombes ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Head Model ◽  
Matching Accuracy ◽  
The People ◽  
Computer Aided ◽  
Closed Head ◽  
The Face ◽  
Aided Design ◽  
Dimensional Surface

The extent to which faces depicted as surfaces devoid of pigmentation and with minimal texture cues (‘head models’) could be matched with photographs (when unfamiliar) and identified (when familiar) was examined in three experiments. The head models were obtained by scanning the three-dimensional surface of the face with a laser, and by displaying the surface measured in this way by using standard computer-aided design techniques. Performance in all tasks was above chance but far from ceiling. Experiment 1 showed that matching of unfamiliar head models with photographs was affected by the resolution with which the surface was displayed, suggesting that subjects based their decisions, at least in part, on three-dimensional surface structure. Matching accuracy was also affected by other factors to do with the viewpoints shown in the head models and test photographs, and the type of lighting used to portray the head model. In experiment 2 further evidence for the importance of the nature of the illumination used was obtained, and it was found that the addition of a hairstyle (not that of the target face) did not facilitate matching. In experiment 3 identification of the head models by colleagues of the people shown was compared with identification of photographs where the hair was concealed and eyes were closed. Head models were identified less well than these photographs, suggesting that the difficulties in their recognition are not solely due to the lack of hair. Women's heads were disproportionately difficult to recognise from the head models. The results are discussed in terms of their implications for the use of such three-dimensional head models in forensic and surgical applications.

scholarly journals Focality of the Induced E-Field Is a Contributing Factor in the Choice of TMS Parameters: Evidence from a 3D Computational Model of the Human Brain

2020 ◽  
Vol 10 (12) ◽  
pp. 1010
Author(s):  
Deepika Konakanchi ◽  
Amy L. de Jongh Curry ◽  
Robert S. Waters ◽  
Shalini Narayana
Keyword(s):  
Spatial Distribution ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Element Model ◽  
Brain Areas ◽  
Invasive Approach ◽  
Non Invasive ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact

Transcranial magnetic stimulation (TMS) is a promising, non-invasive approach in the diagnosis and treatment of several neurological conditions. However, the specific results in the cortex of the magnitude and spatial distribution of the secondary electrical field (E-field) resulting from TMS at different stimulation sites/orientations and varied TMS parameters are not clearly understood. The objective of this study is to identify the impact of TMS stimulation site and coil orientation on the induced E-field, including spatial distribution and the volume of activation in the cortex across brain areas, and hence demonstrate the need for customized optimization, using a three-dimensional finite element model (FEM). A considerable difference was noted in E-field values and distribution at different brain areas. We observed that the volume of activated cortex varied from 3000 to 7000 mm3 between the selected nine clinically relevant coil locations. Coil orientation also changed the induced E-field by a maximum of 10%, and we noted the least optimal values at the standard coil orientation pointing to the nose. The volume of gray matter activated varied by 10% on average between stimulation sites in homologous brain areas in the two hemispheres of the brain. This FEM simulation model clearly demonstrates the importance of TMS parameters for optimal results in clinically relevant brain areas. The results show that TMS parameters cannot be interchangeably used between individuals, hemispheres, and brain areas. The focality of the TMS induced E-field along with its optimal magnitude should be considered as critical TMS parameters that should be individually optimized.

Numerical Study of Welding Sequence on the Residual Stress Field in a Thick-Walled Tee Joint

2011 ◽  
Vol 219-220 ◽  
pp. 1211-1214
Author(s):  
Wei Jiang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Factors Affecting ◽  
Welding Sequence ◽  
Welding Sequences ◽  
Three Dimensional Finite Element

Finite element simulation is an efficient method for studying factors affecting weld-induced residual stress distributions. In this paper, a validated three-dimensional finite element model consisting of sequentially coupled thermal and structural analyses was developed. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were perceived to generate the least distortion in actual welding circumstances, were proposed and their influences on the residual stress fields in a thick-walled tee joint were investigated. Appropriate conclusions and recommendations regarding welding sequences are presented.

Numerical Simulation of Inclined Multi-Seam Mining Subsidence of Considered the Impact by Faults

2011 ◽  
Vol 250-253 ◽  
pp. 2135-2140
Author(s):  
Zhi Ping Wu ◽  
Sheng Hua Qiu ◽  
Ying Li
Keyword(s):  
Working Conditions ◽  
Three Dimensional ◽  
Surface Subsidence ◽  
Differential Settlement ◽  
Geological Condition ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Seam Mining ◽  
The Impact ◽  
Roof Strata

According to the complex mining geological condition of Shandong gentle inclined multi-seam mining, Use the three-dimensional finite element numerical analysis software to establish three-dimensional geological model under the different mining working conditions. Taking into account the impact of faults to calculate multi-seam roof strata movement and surface subsidence caused by the different mining working conditions. The level displacement & subsidence distribution curve of the reference point of surface & multi-seam roof strata under the different working conditions is shown. The maximum, minimum settlement, differential settlement and subsidence diagram is shown. And the principal stress, shear stress value of surface & multi-seam roof strata after mining also is shown. The results showed that: little change of the biggest surface subsidence and differential settlement is caused by mining 3101&3102 face or separate 3101 or 3102 face. And the largest subsidence, and the settlement difference of the surface is 520mm, 498mm, 515mm and 59mm, 78mm, 81mm, Respectively. It provides an reference for reasonable, safe, economic for the inclined multi-seam mining under similar conditions.

Prediction of the yielding behaviour of ductile porous materials through computational homogenization

2018 ◽  
Vol 35 (2) ◽  
pp. 604-621
Author(s):  
Rodrigo Pinto Carvalho ◽  
Igor A. Rodrigues Lopes ◽  
Francisco M. Andrade Pires
Keyword(s):  
Three Dimensional ◽  
Yield Locus ◽  
Analytical Models ◽  
Finite Element Models ◽  
Content Type ◽  
Ductile Materials ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Void Geometry ◽  
The Impact

Purpose The purpose of this paper is to predict the yield locus of porous ductile materials, evaluate the impact of void geometry and compare the computational results with existing analytical models. Design/methodology/approach A computational homogenization strategy for the definition of the elasto-plastic transition is proposed. Representative volume elements (RVEs) containing single-centred ellipsoidal voids are analysed using three-dimensional finite element models under the geometrically non-linear hypothesis of finite strains. Yield curves are obtained by means of systematic analysis of RVEs considering different kinematical models: linear boundary displacements (upper bound), boundary displacement fluctuation periodicity and uniform boundary traction (lower bound). Findings The influence of void geometry is captured and the reduction in the material strength is observed. Analytical models usually overestimate the impact of void geometry on the yield locus. Originality/value This paper proposes an alternative criterion for porous ductile materials and assesses the accuracy of analytical models through the simulation of three-dimensional finite element models under geometrically non-linear hypothesis.

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