Development and Validation of Subject-Specific Finite Element Models for Blunt Trauma Study

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Weixin Shen ◽  
Yuqing Niu ◽  
Robert F. Mattrey ◽  
Adam Fournier ◽  
Jackie Corbeil ◽  
...  
Keyword(s):  
Finite Element ◽  
Ct Images ◽  
Fe Model ◽  
Rib Cage ◽  
Abdominal Organs ◽  
Subject Specific ◽  
Experimental Values ◽  
Thoracic And Abdominal ◽  
Development And Validation ◽  
Good Agreement

This study developed and validated finite element (FE) models of swine and human thoraxes and abdomens that had subject-specific anatomies and could accurately and efficiently predict body responses to blunt impacts. Anatomies of the rib cage, torso walls, thoracic, and abdominal organs were reconstructed from X-ray computed tomography (CT) images and extracted into geometries to build FE meshes. The rib cage was modeled as an inhomogeneous beam structure with geometry and bone material parameters determined directly from CT images. Meshes of soft components were generated by mapping structured mesh templates representative of organ topologies onto the geometries. The swine models were developed from and validated by 30 animal tests in which blunt insults were applied to swine subjects and CT images, chest wall motions, lung pressures, and pathological data were acquired. A comparison of the FE calculations of animal responses and experimental measurements showed a good agreement. The errors in calculated response time traces were within 10% for most tests. Calculated peak responses showed strong correlations with the experimental values. The stress concentration inside the ribs, lungs, and livers produced by FE simulations also compared favorably to the injury locations. A human FE model was developed from CT images from the Visible Human project and was scaled to simulate historical frontal and side post mortem human subject (PMHS) impact tests. The calculated chest deformation also showed a good agreement with the measurements. The models developed in this study can be of great value for studying blunt thoracic and abdominal trauma and for designing injury prevention techniques, equipments, and devices.

Development and Validation of a Subject-Specific Finite Element Model for Skull Fracture Assessment

2011 ◽  
Author(s):  
James Huang ◽  
David Raymond ◽  
Weixin Shen ◽  
James Stuhmiller ◽  
Gregory Crawford ◽  
...  
Keyword(s):  
Finite Element ◽  
Skull Fracture ◽  
Assessment Tools ◽  
Fe Model ◽  
Accelerometer Data ◽  
Head Impacts ◽  
Fracture Patterns ◽  
Subject Specific ◽  
Strain Data ◽  
Development And Validation

Due to the frequent occurrence of skull fractures from unintended head impacts from kinetic energy weapons, there is an immediate need to develop injury assessment tools for evaluating the risk of skull fracture under the high speed projectile impacts. Skull fracture tolerance has been shown to be dependent on impactor characteristics such as size and shape, as well as subject-specific anatomy. Accurate strain data collected at the fracture location has historically been difficult to measure, which has led to the use of finite element models. Prior research however has used generic finite element (FE) models of the head to determine skull strain and establish FE-based fracture criteria and thus may not be reflective of actual strain in the experimental tests, leading to inaccurate criteria. Additionally, prior FE models have not demonstrated the ability to accurately model fracture patterns. This study reports on two blunt ballistic temporo-parietal head impacts carried out to a post-mortem human subject (PMHS) and the development and validation of a subject-specific FE model. A nine-accelerometer array was mounted to the frontal bone to measure linear and rotational head accelerations. Three rectangular Rosette-style strain gauges were utilized to collect bone strain data surrounding the impact sites. A rigid, flat-faced 38.1 mm diameter projectile with a mass of 0.1 kg was used for all impacts. An accelerometer was mounted to the rear aspect of the projectile for measurement of impactor acceleration and from which impact force was calculated using the projectile mass and applying Newton’s Second Law. A subject-specific finite element head model was developed from the PMHS CT images. Results demonstrated good correlation between experimentally collected strain and accelerometer data to the FE model. The fracture patterns predicted from the model also demonstrated good agreement to fractures observed in the PMHS.

Simulation and Optimization of Wedge-Shaped Ultrasonic Transducers Using Finite Element Method (FEM)

2013 ◽  
Vol 281 ◽  
pp. 112-115 ◽  
Author(s):  
Dan Jin ◽  
Zhao Hui Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Effect ◽  
Ultrasonic Transducers ◽  
Fe Model ◽  
Limited Size ◽  
Simulation And Optimization ◽  
Ultrasonic Flaw ◽  
Shape And Size ◽  
Good Agreement

Wedge-shaped transducers have been widely used in industry as probes for ultrasonic flowmeters or for ultrasonic flaw detectors. But by now, few studies have focused on the influence to the performance of the wedge-shaped transducers brought by their limited size. In this paper, the effect of the shape and size of wedge-shaped substrates on the whole transducer system is discussed and the shape and size of a transducer (0.5MHz) is optimized to eliminate the influence of the boundary effect by using a 2-D Finite Element (FE) model. Lastly, wedge-shaped transducers have been manufactured for experiment which shows a good agreement with the simulation.

Residual Stress Prediction for Non-Axisymmetric Vessel Penetration Welds

2008 ◽  
Author(s):  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Measurement Data ◽  
Fe Model ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Stress Prediction ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Residual stress distribution in an oblique nozzle jointed to a vessel with J-groove welds was analyzed using a three-dimensional finite element method. All welding passes were considered in a 180-degree finite element (FE) model with symmetry. Temperature and stress were modeled for simultaneous bead laying. To determine residual stress distributions at the welds experimentally, a mock-up specimen was manufactured. The analytical results show good agreement with the experimental measurement data, indicating that FE modeling is valid.

An assessment of the Sachs method for measuring residual stresses in cold worked fastener holes

1998 ◽  
Vol 33 (4) ◽  
pp. 263-274 ◽  
Author(s):  
D J Smith ◽  
C G C Poussard ◽  
M J Pavier
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Cold Working ◽  
Element Model ◽  
Fe Model ◽  
Working Process ◽  
Element Analysis ◽  
Near Surface ◽  
Cold Worked ◽  
Good Agreement

Measurements of residual stresses in 6 mm thick aluminium alloy 2024 plates containing 4 per cent cold worked fastener are made using the Sachs method. The measurements are made on discs extracted from the plates. The measured tangential residual stress distribution adjacent to the hole edge are found to be affected by the disc diameter. The measured residual stresses are also in good agreement with averaged through-thickness predictions of residual stresses from an axisymmetric finite element (FE) model of the cold working process. A finite element analysis is also conducted to simulate disc extraction and then the Sachs method. The measured FE residual stresses from the Sachs simulation are found to be in good agreement with the averaged through-thickness predicted residual stresses. The Sachs simulation was not able to reproduce the detailed near-surface residual stresses found from the finite element model of the cold working process.

Micromechanical Model of a Collagen Based Tendon Surrogate: Development and Validation

2012 ◽  
Author(s):  
Shawn P. Reese ◽  
Jeffrey A. Weiss
Keyword(s):  
Finite Element ◽  
Computational Model ◽  
Physical Model ◽  
Micromechanical Model ◽  
Tensile Loading ◽  
Fe Model ◽  
Damage Mechanisms ◽  
High Importance ◽  
Force Transfer ◽  
Development And Validation

In tendons and ligaments, collagen is organized hierarchically into nanoscale fibrils, microscale fibers and mesoscale fascicles. Force transfer across scales is complex and poorly understood, and macroscale strains are not representative of the microscale strains [1]. Since innervation, the vasculature, damage mechanisms and mechanotransduction occur at the microscale, understanding such multiscale interactions is of high importance. In this study, a physical model was used in combination with a computational model to isolate and study the mechanisms of force transfer between scales. The objectives of this study were to develop a collagen based tendon surrogate for use as a physical model and subject it to tensile loading, and to create and validate a 3D micromechanical finite element (FE) model of the surrogate.

scholarly journals Evaluation of Self-Propelled Rotary Tool in the Machining of Hardened Steel Using Finite Element Models

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5092
Author(s):  
Usama Umer ◽  
Hossam Kishawy ◽  
Mustufa Haider Abidi ◽  
Syed Hammad Mian ◽  
Khaja Moiduddin
Keyword(s):  
Finite Element ◽  
Cutting Tool ◽  
Hardened Steel ◽  
Heat Transfer Analysis ◽  
Fe Model ◽  
Rotary Tool ◽  
Chip Flow ◽  
Heat Partitioning ◽  
Rotary Cutting ◽  
Good Agreement

This paper presents a model for assessing the performance of self-propelled rotary tool during the processing of hardened steel. A finite element (FE) model has been proposed in this analysis to study the hard turning of AISI 51200 hardened steel using a self-propelled rotary cutting tool. The model is developed by utilizing the explicit coupled temperature displacement analysis in the presence of realistic boundary conditions. This model does not take into account any assumptions regarding the heat partitioning and the tool-workpiece contact area. The model can predict the cutting forces, chip flow, induced stresses, and the generated temperature on the cutting tool and the workpiece. The nodal temperatures and heat flux data from the chip formation analysis are used to achieve steady-state temperatures on the cutting tool in the heat transfer analysis. The model outcomes are compared with reported experimental data and a good agreement has been found.

Subject-Specific Finite Element Models of the Tibia With Realistic Boundary Conditions Predict Bending Deformations Consistent With In Vivo Measurement

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Ifaz T. Haider ◽  
Michael Baggaley ◽  
W. Brent Edwards
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Internal Rotation ◽  
Stress Fracture ◽  
Contact Forces ◽  
Female Participant ◽  
Fe Model ◽  
In Vivo Measurements ◽  
Subject Specific

Abstract Understanding the structural response of bone during locomotion may help understand the etiology of stress fracture. This can be done in a subject-specific manner using finite element (FE) modeling, but care is needed to ensure that modeling assumptions reflect the in vivo environment. Here, we explored the influence of loading and boundary conditions (BC), and compared predictions to previous in vivo measurements. Data were collected from a female participant who walked/ran on an instrumented treadmill while motion data were captured. Inverse dynamics of the leg (foot, shank, and thigh segments) was combined with a musculoskeletal (MSK) model to estimate muscle and joint contact forces. These forces were applied to an FE model of the tibia, generated from computed tomography (CT). Eight conditions varying loading/BCs were investigated. We found that modeling the fibula was necessary to predict realistic tibia bending. Applying joint moments from the MSK model to the FE model was also needed to predict torsional deformation. During walking, the most complex model predicted deformation of 0.5 deg posterior, 0.8 deg medial, and 1.4 deg internal rotation, comparable to in vivo measurements of 0.5–1 deg, 0.15–0.7 deg, and 0.75–2.2 deg, respectively. During running, predicted deformations of 0.3 deg posterior, 0.3 deg medial, and 0.5 deg internal rotation somewhat underestimated in vivo measures of 0.85–1.9 deg, 0.3–0.9 deg, 0.65–1.72 deg, respectively. Overall, these models may be sufficiently realistic to be used in future investigations of tibial stress fracture.

Compressive Behavior of AA6061 at Room Temperature and Validation of the FE Model Based on Optical 3D Measurement Technique

2013 ◽  
Vol 594-595 ◽  
pp. 909-913
Author(s):  
A.B. Abdullah ◽  
Z. Samad
Keyword(s):  
Finite Element ◽  
Measurement Technique ◽  
Room Temperature ◽  
Element Model ◽  
Surface Measurement ◽  
Fe Model ◽  
Cold Upsetting ◽  
Element Simulation ◽  
The Finite Element Model ◽  
Good Agreement

Recently, manufacturing process simulation using finite element (FE) model become important. Therefore, validation of the finite element model is crucial. This study will present validation of 2D finite element simulation of cold heading at room temperature. Validation of the simulation model is carried out by comparing the resulted bulge profile of the cold upsetting specimen to the profile of the specimen, which is obtained from an optical 3D surface measurement technique namely Infinite Focus Alicona system. Based on the result, both profiles show a very good agreement.

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