Biomechanical Comparison of Real World Concussive Impacts in Children, Adolescents, and Adults

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Lauren Dawson ◽  
David Koncan ◽  
Andrew Post ◽  
Roger Zemek ◽  
Michael D. Gilchrist ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Brain Tissue ◽  
Dynamic Models ◽  
Element Model ◽  
Tissue Response ◽  
Model Simulations ◽  
Child Group ◽  
Adolescents And Adults ◽  
The Impact

Abstract Accidental falls occur to people of all ages, with some resulting in concussive injury. At present, it is unknown whether children and adolescents are at a comparable risk of sustaining a concussion compared to adults. This study reconstructed the impact kinematics of concussive falls for children, adolescents, and adults and simulated the associated brain tissue deformations. Patients included in this study were diagnosed with a concussion as defined by the Zurich Consensus guidelines. Eleven child, 10 adolescent, and 11 adult falls were simulated using mathematical dynamic models(MADYMO), with three ellipsoid pedestrian models sized to each age group. Laboratory impact reconstruction was conducted using Hybrid III head forms, with finite element model simulations of the brain tissue response using recorded impact kinematics from the reconstructions. The results of the child group showed lower responses than the adolescent group for impact variables of impact velocity, peak linear acceleration, and peak rotational acceleration but no statistical differences existed for any other groups. Finite element model simulations showed the child group to have lower strain values than both the adolescent and adult groups. There were no statistical differences between the adolescent and adult groups for any variables examined in this study. With the cases included in this study, young children sustained concussive injuries at lower modeled brain strains than adolescents and adults, supporting the theory that children may be more susceptible to concussive impacts than adolescents or adults.

Behavior of Structures Using Simple Plastic Hinge Theory

1994 ◽  
Author(s):  
Ramakrishnan Maruthayappan ◽  
Hamid M. Lankarani
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cantilever Beam ◽  
Reliable Method ◽  
Plastic Hinge ◽  
Element Model ◽  
Finite Element Models ◽  
Computational Program ◽  
Hinge Model ◽  
The Impact

Abstract The behavior of structures under the impact or crash situations demands an efficient modeling of the system for its behavior to be predicted close to practical situations. The various formulations that are possible to model such systems are spring mass models, finite element models and plastic hinge models. Of these three techniques, the plastic hinge theory offers a more accurate model compared to the spring mass formulation and is much simpler than the finite element models. Therefore, it is desired to model the structure using plastic hinges and to use a computational program to predict the behavior of structures. In this paper, the behavior of some simple structures, ranging from an elementary cantilever beam to a torque box are predicted. It is also shown that the plastic hinge theory is a reliable method by comparing the results obtained from a plastic hinge model of an aviation seat structure with that obtained from a finite element model.

Experimentally validated predictive finite element modeling of the V0-V100 probabilistic penetration response of a Kevlar fabric against a spherical projectile

2018 ◽  
Vol 9 (4) ◽  
pp. 504-524 ◽  
Author(s):  
Gaurav Nilakantan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Element Model ◽  
Ballistic Impact ◽  
Impact Testing ◽  
Woven Fabric ◽  
Projectile Impact ◽  
Element Modeling ◽  
The Impact

This work presents the first fully validated and predictive finite element modeling framework to generate the probabilistic penetration response of an aramid woven fabric subjected to ballistic impact. This response is defined by a V0-V100 curve that describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this article comprises a single-layer, fully clamped, plain-weave Kevlar fabric impacted at the center by a 0.22 cal spherical steel projectile. The fabric finite element model comprises individually modeled three-dimensional warp and fill yarns and is validated against the experimental material microstructure. Sources of statistical variability including yarn strength and modulus, inter-yarn friction, and precise projectile impact location are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, each comprising unique mappings. The impact velocities and outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve obtained from ballistic impact testing and shown to be in excellent agreement. The experimental data and its statistical analysis used for model input and validation, namely, the Kevlar yarn tensile strengths and moduli, inter-yarn friction, and fabric ballistic impact testing, are also reported.

scholarly journals Characterization of Adhesives Bonding in Aircraft Structures

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4816
Author(s):  
Maria Grazia Romano ◽  
Michele Guida ◽  
Francesco Marulo ◽  
Michela Giugliano Auricchio ◽  
Salvatore Russo
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Finite Element Model ◽  
Impact Energy ◽  
Element Model ◽  
Cohesive Zone Modeling ◽  
Main Task ◽  
Opening Displacement ◽  
Lap Shear ◽  
The Impact

Structural adhesives play an important role in aerospace manufacturing, since they provide fewer points of stress concentration compared to faster joints. The importance of adhesives in aerospace is increasing significantly because composites are being adopted to reduce weight and manufacturing costs. Furthermore, adhesive joints are also studied to determine the crashworthiness of airframe structure, where the main task for the adhesive is not to dissipate the impact energy, but to keep joint integrity so that the impact energy can be consumed by plastic work. Starting from an extensive campaign of experimental tests, a finite element model and a methodology are implemented to develop an accurate adhesive model in a single lap shear configuration. A single lap joint finite element model is built by MSC Apex, defining two specimens of composite material connected to each other by means of an adhesive; by the Digimat multi-scale modeling solution, the composite material is treated; and finally, by MSC’s Marc, the adhesive material is characterized as a cohesive applying the Cohesive Zone Modeling theory. The objective was to determine an appropriate methodology to predict interlaminar crack growth in composite laminates, defining the mixed mode traction separation law variability in function of the cohesive energy (Gc), the ratio between the shear strength τ and the tensile strength σ (β1), and the critical opening displacement υc.

Structural Optimization Scheme for Horizontal Filtering Tank

2014 ◽  
Vol 577 ◽  
pp. 310-313
Author(s):  
Ping Yang ◽  
Zhou De Qu ◽  
Min Li
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Finite Element Model ◽  
Element Model ◽  
Structural Instability ◽  
Optimization Scheme ◽  
Design Scheme ◽  
Operation Process ◽  
The Impact ◽  
The Finite Element Model

Based on the impact of some horizontal filtering tank’s instability in operation process on production, the present paper discusses the optimal design scheme for horizontal filtering tank structure with the help of finite element. Theoretical guidance will be given to enterprise from the perspective of finite element for the purpose of improving the horizontal filtering tank through constructing the finite element model for horizontal filtering tank with Creo parametric software, conducting simulation with workbench software[1] and finally arriving at the reasonable design scheme after analysis, thus avoiding the structural instability caused by the over-constraint of structural leg support beam and filter plate under-constraint.

Two-dimensional finite element model to study temperature distribution in peripheral regions of extended spherical human organs involving uniformly perfused tumors

2015 ◽  
Vol 08 (06) ◽  
pp. 1550074 ◽  
Author(s):  
Akshara Makrariya ◽  
Neeru Adlakha
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Finite Element Model ◽  
Metabolic Activity ◽  
Element Model ◽  
The Body ◽  
Tissue Response ◽  
Two Dimensional ◽  
Human Breast ◽  
Peripheral Regions

Temperature as an indicator of tissue response is widely used in clinical applications. In view of above a problem of temperature distribution in peripheral regions of extended spherical organs of a human body like, human breast involving uniformly perfused tumor is investigated in this paper. The human breast is assumed to be spherical in shape with upper hemisphere projecting out from the trunk of the body and lower hemisphere is considered to be a part of the body core. The outer surface of the breast is assumed to be exposed to the environment from where the heat loss takes place by conduction, convection, radiation and evaporation. The heat transfer from core to the surface takes place by thermal conduction and blood perfusion. Also metabolic activity takes place at different rates in different layers of the breast. An elliptical-shaped tumor is assumed to be present in the dermis region of human breast. A finite element model is developed for a two-dimensional steady state case incorporating the important parameters like blood flow, metabolic activity and thermal conductivity. The triangular ring elements are employed to discretize the region. Appropriate boundary conditions are framed using biophysical conditions. The numerical results are used to study the effect of tumor on temperature distribution in the region.

Description and Validation of a Finite Element Model of Backflow During Infusion Into a Brain Tissue Phantom

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
José J. García ◽  
Ana Belly Molano ◽  
Joshua H. Smith
Keyword(s):  
Finite Element ◽  
Hydraulic Conductivity ◽  
Finite Element Model ◽  
Brain Tissue ◽  
Nonlinear Boundary ◽  
Fluid Pressure ◽  
Element Model ◽  
Analytical Models ◽  
External Boundary ◽  
Forward Flow

An axisymmetric biphasic finite element model is proposed to simulate the backflow that develops around the external boundary of the catheter during flow-controlled infusions. The model includes both material and geometric nonlinearities and special treatments for the nonlinear boundary conditions used to represent the forward flow from the catheter tip and the axial backflow that occurs in the annular gap that develops as the porous medium detaches from the catheter. Specifically, a layer of elements with high hydraulic conductivity and low Young’s modulus was used to represent the nonlinear boundary condition for the forward flow, and another layer of elements with axial hydraulic conductivity consistent with Poiseuille flow was used to represent the backflow. Validation of the model was performed by modifying the elastic properties of the latter layer to fit published experimental values for the backflow length and maximum fluid pressure obtained during infusions into agarose gels undertaken with a 0.98-mm-radius catheter. Next, the finite element model predictions showed good agreement with independent experimental data obtained for 0.5-mm-radius and 0.33-mm-radius catheters. Compared to analytical models developed by others, this finite element model predicts a smaller backflow length, a larger fluid pressure, and a substantially larger percentage of forward flow. This latter difference can be explained by the important axial flow in the tissue that is not considered in the analytical models. These results may provide valuable guidelines to optimize protocols during future clinical studies. The model can be extended to describe infusions in brain tissue and in patient-specific geometries.

The Analysis on Suspension of Fire Robot Based on FEA

2014 ◽  
Vol 716-717 ◽  
pp. 1536-1539
Author(s):  
Yan Xu ◽  
Shu Fang ◽  
Jian Qiao Fu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stress Condition ◽  
Impact Load ◽  
Element Model ◽  
Force Condition ◽  
Environmental Adaptability ◽  
The Impact ◽  
Suspension Structure

The suspension of fire robot, one of necessary components, directly impacts the environmental adaptability, and the strength of suspension has great importance to the life of robot. In the paper, the structure and the stress condition of the suspension was analyzed. The force condition of suspension is simplified as a 2-D diagram, the load acting on the elbow were simplified in two direction, A finite element model, which simulated the impact load and optimized the design of suspension, was established, and the result of the simulation shows the suspension structure is reasonable and the strength of the component is enough.

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