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 Microstructural Modeling of Rheological Mechanical Response for Asphalt Mixture Using an Image-Based Finite Element Approach

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2041 ◽  
Author(s):  
Wenke Huang ◽  
Hao Wang ◽  
Yingmei Yin ◽  
Xiaoning Zhang ◽  
Jie Yuan
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Micromechanical Model ◽  
Asphalt Mixture ◽  
Simulation Software ◽  
Fe Model ◽  
Finite Element Approach ◽  
X Ray ◽  
Element Approach ◽  
Asphalt Mortar

In this paper, an image-based micromechanical model for an asphalt mixture’s rheological mechanical response is introduced. Detailed information on finite element (FE) modeling based on X-ray computed tomography (X-ray CT) is presented. An improved morphological multiscale algorithm was developed to segment the adhesive coarse aggregate images. A classification method to recognize the different classifications of the elemental area for a confining pressure purpose is proposed in this study. Then, the numerical viscoelastic constitutive formulation of asphalt mortar in an FE code was implemented using the simulation software ABAQUS user material subroutine (UMAT). To avoid complex experiments in determining the time-dependent Poisson’s ratio directly, numerous attempts were made to indirectly obtain all material properties in the viscoelastic constitutive model. Finally, the image-based FE model incorporated with the viscoelastic asphalt mortar phase and elastic aggregates was used for triaxial compressive test simulations, and a triaxial creep experiment under different working conditions was conducted to identify and validate the proposed finite element approach. The numerical simulation and experimental results indicate that the three-dimensional microstructural numerical model established can effectively analyze the material’s rheological mechanical response under the effect of triaxial load within the linear viscoelastic range.

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.

scholarly journals Development and validation of a timely and representative finite element human spine model for biomechanical simulations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ibrahim El Bojairami ◽  
Khaled El-Monajjed ◽  
Mark Driscoll
Keyword(s):  
Finite Element ◽  
Assessment Tool ◽  
State Of The Art ◽  
Angular Displacement ◽  
Fe Model ◽  
Low Back ◽  
Spine Model ◽  
Crucial Information ◽  
Validation Tests ◽  
Development And Validation

AbstractNumerous spine Finite Element (FE) models have been developed to assess spinal tolerances, spinal loadings and low back pain-related issues. However, justified simplifications, in terms of tissue decomposition and inclusion, for such a complex system may overlook crucial information. Thus, the purpose of this research was to develop and validate a comprehensive and representative spine FE model inclusive of an accurate representation of all major torso elements. A comprehensive model comprised of 273 tissues was developed via a novel FE meshing method to enhance computational feasibility. A comprehensive set of indirect validation tests were carried out to validate every aspect of the model. Under an increasing angular displacement of 24°–41°, the lumbar spine recorded an increasing moment from 5.5 to 9.3 Nm with an increase in IVD pressures from 0.41 to 0.66 MPa. Under forward flexion, vertical vertebral displacements simulated a 6% and 13% maximum discrepancy for intra-abdominal and intramuscular pressure results, all closely resembling previously documented in silico measured values. The developed state-of-the-art model includes most physiological tissues known to contribute to spinal loadings. Given the simulation’s accuracy, confirmed by its validation tests, the developed model may serve as a reliable spinal assessment tool.

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.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

scholarly journals Influence of finite element mesh size on the carrying capacity analysis of single-row ball slewing bearing

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Peiyu He ◽  
Qinrong Qian ◽  
Yun Wang ◽  
Hong Liu ◽  
Erkuo Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Mesh Size ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Mesh ◽  
Heavy Load ◽  
Slewing Bearing ◽  
Maximum Contact ◽  
Slewing Bearings

Slewing bearings are widely used in industry to provide rotary support and carry heavy load. The load-carrying capacity is one of the most important features of a slewing bearing, and needs to be calculated cautiously. This paper investigates the effect of mesh size on the finite element (FE) analysis of the carrying capacity of slewing bearings. A local finite element contact model of the slewing bearing is firstly established, and verified using Hertz contact theory. The optimal mesh size of finite element model under specified loads is determined by analyzing the maximum contact stress and the contact area. The overall FE model of the slewing bearing is established and strain tests were performed to verify the FE results. The effect of mesh size on the carrying capacity of the slewing bearing is investigated by analyzing the maximum contact load, deformation, and load distribution. This study of finite element mesh size verification provides an important guidance for the accuracy and efficiency of carrying capacity of slewing bearings.

Finite Element Analysis of the Distributed Vibration Absorbers for Structural Noise Control

2005 ◽  
Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Base Plate ◽  
Element Model ◽  
Fe Model ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Poroelastic Media ◽  
Hexahedral Elements ◽  
Component Models

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.

Damage mechanisms and energy absorption of aluminosilicate glass under compression/tensile loading

2021 ◽  
Vol 288 ◽  
pp. 123088
Author(s):  
Muhammad Zakir Sheikh ◽  
Muhammad Atif ◽  
Yulong Li ◽  
Fenghua Zhou ◽  
Muhammad Aamir Raza ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Tensile Loading ◽  
Aluminosilicate Glass ◽  
Damage Mechanisms

scholarly journals Finite element modelling of microstructural changes during equal channel angular drawing of pure aluminium

2021 ◽  
Author(s):  
Serafino Caruso ◽  
Stano Imbrogno
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Finite Element ◽  
Size Variation ◽  
Fe Model ◽  
Pure Aluminium ◽  
Continuous Dynamic Recrystallization ◽  
Research Activities ◽  
Hardness Change ◽  
Continuous Dynamic

AbstractGrain refinement by severe plastic deformation (SPD) techniques, as a mechanism to control microstructure (recrystallization, grain size changes,…) and mechanical properties (yield strength, ultimate tensile strength, strain, hardness variation…) of pure aluminium conductor wires, is a topic of great interest for both academic and industrial research activities. This paper presents an innovative finite element (FE) model able to describe the microstructural evolution and the continuous dynamic recrystallization (CDRX) that occur during equal channel angular drawing (ECAD) of commercial 1370 pure aluminium (99.7% Al). A user subroutine has been developed based on the continuum mechanical model and the Hall-Petch (H-P) equations to predict grain size variation and hardness change. The model is validated by comparison with the experimental results and a predictive analysis is conducted varying the channel die angles. The study provides an accurate prediction of both the thermo-mechanical and the microstructural phenomena that occur during the process characterized by large plastic deformation.

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