scholarly journals Measured Impact

2018 ◽  
Vol 140 (01) ◽  
pp. 42-45
Author(s):  
James G. Skakoon
Keyword(s):  
Finite Element ◽  
Corpus Callosum ◽  
Degrees Of Freedom ◽  
Head Injuries ◽  
Analysis Model ◽  
Element Analysis ◽  
Falx Cerebri ◽  
Institute Of Technology ◽  
The Impact ◽  
The Brain

This article focuses on an innovative methodology developed by researchers at Stanford University. The new way of measuring the forces that cause head injuries aim to change how engineers protect professional and weekend athletes. By embedding both accelerometers and gyroscopes within the mouth guards, the laboratory tracked all six degrees of freedom and slashed data errors to 10 percent or less. According to one of the developer, since the upper teeth are firmly coupled to the bones of the cranium, the mouthguards can provide data accurate enough for the lab to use in finite element models to describe what is happening inside the brain. The team input the incident’s kinematics data into a finite element analysis model of the brain developed by the KTH Royal Institute of Technology in Sweden. This enabled them to simulate how different structures within the brain responded to the impact. The computer simulation showed that the falx cerebri appears to be the culprit. It is a rigid vertical sheet that separates the brain’s two lobes. It lies right above the corpus callosum and extends upward, attaching to the skull at the very top. It conducts impact energy from the skull deep into the brain, where it oscillates and induces strain in the corpus callosum.

An Analytical Viscoelastic Model of the Head in Blunt Impacts

2008 ◽  
Author(s):  
Shahab Baghaei ◽  
Ali Sadegh ◽  
Mohamad Rajaai
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Spherical Shell ◽  
Head Injuries ◽  
Head Impacts ◽  
Closed Head Injuries ◽  
Brain Motion ◽  
Closed Head ◽  
The Impact ◽  
The Brain

The relative motion between the brain and skull and an increase in contact and shear stresses in the meningeal region could cause traumatic closed head injuries due to vehicular collisions, sport accidents and falls. There are many finite element studies of the brain/head models, but limited analytical models. The goal of this paper is to mathematically model subarachnoid space and the meningeal layers and to investigate the motion of the brain relative to the skull during blunt head impacts. The model consists of an elastic spherical shell representing the skull containing a visco-elastic solid material as the brain and a visco-elastic interface, which models the meningeal layers between the brain and the skull. In this study, the shell (the head) is moved toward a barrier and comes in contact with the barrier. Consequently, the skull deforms elastically and the brain is excited to come in contact with the skull. The viscoelastic characteristics of the interface (consisting of springs and dampers) are determined using experimental results of Hardy et al. [5]. Hertzian contact theory and Newtonian method are employed to acquire time dependant equations for the problem. The governing nonlinear integro-differential equations are formed and are solved using 4th order Runge Kutta method and elastic deformation of spherical shell, brain motion during the impact, and contact conditions between the brain and the skull are evaluated. Furthermore, some important mechanical parameters such as acceleration, impact force, and the impact time duration are also specified. The results of the analytical method are validated by performing an explicit finite element analysis. Acceptable agreement between these two methods is observed. The results of the analytical investigation give the contact threshold of the skull/brain, and represent the relevant velocity of this event. Furthermore, the impact analysis in different velocities is performed in order to compare the transmitted forces and the impact durations in different cases. It is concluded that the proposed mathematical model can predict head impacts in accidents and is capable in determining the relative brain motion of the skull and the brain. The mathematical model could be employed by other investigators to parametrically study the traumatic closed head injuries and hence to propose new head injury criteria.

Multiaxial Impact Behavior and Modeling of ABS Polymer

2001 ◽  
Author(s):  
A. Saigal ◽  
R. Greif ◽  
Y. Duan ◽  
M. A. Zimmerman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Rate ◽  
Impact Load ◽  
Mechanical Test ◽  
Impact Behavior ◽  
Analysis Model ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
The Impact

Abstract The multiaxial impact behavior of CYCOLAC GPM5500 (ABS glassy polymer) is obtained as a function of impact velocity and temperature from the standard impact test as specified by ASTM D3763. Finite element analysis (FEA) and ABAQUS/Explicit are used to model the impact behavior of the polymer. The generalized “DSGZ” constitutive model, previously developed by the authors and calibrated using low strain rate uniaxial mechanical test data, is extended to the high strain rate regime and used in the finite element analysis. Load-displacement curves from the finite element analysis are compared with the experimental data and agree well up to the maximum impact load (failure). Therefore, the proposed finite element analysis model can be used to predict the multiaxial impact behaviors of polymers at different temperatures and impact velocities.

Head Injury in Facial Impact—A Finite Element Analysis of Helmet Chin Bar Performance

2000 ◽  
Vol 122 (6) ◽  
pp. 640-646 ◽  
Author(s):  
Chih-Han Chang ◽  
Li-Tung Chang ◽  
Guan-Liang Chang ◽  
Shyh-Chour Huang ◽  
Chiou-Hua Wang
Keyword(s):  
Finite Element ◽  
Head Injury ◽  
Head Injuries ◽  
Element Analysis ◽  
Maximum Acceleration ◽  
Explicit Finite Element ◽  
Motorcycle Helmet ◽  
Energy Absorbing ◽  
Protective Performance ◽  
The Impact

The chin bar of a motorcycle helmet protects the rider from facial and head injuries. To evaluate the protective performance of chin bars against head injuries from facial impacts, an explicit finite element method was used to simulate the Snell Memorial Foundation test and a proposed drop test. The maximum acceleration and Head Injury Criterion (HIC) were employed to assess the impact-absorbing capability of the chin bar. The results showed that the proposed approach should be more practical than the Snell test, and provided more information for improving the chin bar design to protect against head injuries. The shell stiffness was important in determining the protective ability of the chin bar, but a chin bar with only an outer shell and comfort foam offered inadequate protection. An energy-absorbing liner was essential to increase the protective performance of the chin bar and the liner density should be denser than that used in the cranial portion of the helmet. For the chin bar with energy-absorbing liner, a shell design that is less stiff would provide better protection. [S0148-0731(00)01206-1]

Dynamic Response of the Human Head to Impact by Three-Dimensional Finite Element Analysis

1994 ◽  
Vol 116 (1) ◽  
pp. 44-50 ◽  
Author(s):  
J. S. Ruan ◽  
T. Khalil ◽  
A. I. King
Keyword(s):  
Finite Element ◽  
Fluid Layer ◽  
Three Dimensional ◽  
Human Head ◽  
Frontal Impact ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact ◽  
The Brain

The impact response of the human head has been determined by three-dimensional finite element modeling. This model represents the essential features of a 50th percentile human head. It includes a layered shell closely representing the cranial bones with the interior contents occupied by an inviscid continuum to simulate the brain. A thin fluid layer was included to represent the cerebral-spinal fluid. To validate the model, its response was obtained by applying a sine-squared pulse of 6.8 kN in magnitude and 10 ms in duration. The load was applied to a freely supported head on the frontal bone in the midsagittal plane. The computed pressure-time histories at 5 locations within the brain material compared quite favorably with previously published experimental data from cadaver experiments and provided a reasonable level of confidence in the validation of the model. A parametric study was subsequently conducted to identify the model response when the impact site (frontal, side, occipital) and the material properties of the head were varied. Interestingly, the model predicted higher contre-coup pressure in the frontal lobe (from occipital impact) than that predicted in the occipital region from frontal impact. This finding supports clinical findings of contre-coup injury being more likely to result from occipital impact than from frontal impact.

The Finite Element Analysis of FOPS for the Loader

2011 ◽  
Vol 467-469 ◽  
pp. 1616-1620 ◽  
Author(s):  
Xin Zhang ◽  
Meng Zang ◽  
Xiao Zhe Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optimization Design ◽  
Impact Load ◽  
Analysis Model ◽  
Element Analysis ◽  
Reliability Design ◽  
Maximum Deformation ◽  
The Finite Element Analysis ◽  
The Impact

The finite element analysis method of falling-object protective structure (FOPS) for the loader is presented in this paper. Taking FOPS for CL958 type loader as an example, this paper builds the analysis model in ANSYS, obtains the displacement of the load center and the maximum deformation of FOPS caused by the impact load and proves the safety by the drop test. It provides the theoretical basis and design principle for the optimization design and reliability design of FOPS for the loader.

The Mechanical Property Comparison of Two Kinds of Counterweight Booms of Stacker Reclaimer

2013 ◽  
Vol 690-693 ◽  
pp. 1966-1971
Author(s):  
Peng Shang ◽  
Kai Cheng Qi ◽  
Ya Xu Wang ◽  
Yu Ming Guan
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Large Scale ◽  
The Finite Element Method ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Different Types ◽  
The Impact

This paper used the finite element method to compare the mechanical properties of two different configuration counterweight booms of the bucket wheel stacker reclaimer. And two different forms of the finite element analysis model of the counterweight booms were built in ANSYS. The stresses and strains under its working state were calculated. Then the impact of the counterweight arm to the force and stability of the whole rack could be analyzed. The results of this analysis provided a basis to select different types of the counterweight booms in different environment, and it has an important guidance and reference significance to the design and analysis of counterweight booms of large-scale machinery.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

scholarly journals Parametric Evaluation of 11kV Zinc Oxide Surge Arrester using Finite Element Analysis Model

2021 ◽  
Vol 1127 (1) ◽  
pp. 012038
Author(s):  
A.A. Latiff Nurul ◽  
Z.A. Dabbak Sameh ◽  
A. Illias Hazlee ◽  
Ab H.A. Bakar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Zinc Oxide ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model

scholarly journals The impact of bone and suture material properties on mandibular function in Alligator mississippiensis: testing theoretical phenotypes with finite element analysis

2010 ◽  
Vol 218 (1) ◽  
pp. 59-74 ◽  
Author(s):  
David A. Reed ◽  
Laura B. Porro ◽  
Jose Iriarte-Diaz ◽  
Justin B. Lemberg ◽  
Casey M. Holliday ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Suture Material ◽  
Alligator Mississippiensis ◽  
Element Analysis ◽  
The Impact
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