Finite Element Model of a Cell Incorporating Cell Membrane, Cytoskeletal Structure and Intracellular Fluid Pressure

2002 ◽  
Author(s):  
Vidyashankar Venkatesan ◽  
Nilay Mukherjee
Keyword(s):  
Finite Element ◽  
Compressive Loading ◽  
Fluid Pressure ◽  
Element Model ◽  
Structural Components ◽  
Element Analysis ◽  
In Situ Experiments ◽  
A Cell

Compressive loading is intrinsic to certain tissues in our body like articular cartilage and bone (1). In situ experiments in cartilage suggest that chondrocytes can undergo significant deformation due to compressive loading on the tissue (2). In situ and isolated cell experiments have concluded that cells are quite resilient to compressive loading, aspiration etc. and exhibit a moduli in the range of 0.6 to 2 kPa (3). However, few studies have attempted to understand the compressive behavior of cells in terms of its structural components. The structural components of a cell consist of a membrane and a dense network of at least three elements (actin, microtubules and intermediate filaments). Using finite element analysis techniques we wanted to explore the role of these structural components in determining the ability of the cell to withstand compression.

Finite element analysis of hydrogen effects on superelastic NiTi shape memory alloys: Orthodontic application

2018 ◽  
Vol 29 (16) ◽  
pp. 3188-3198 ◽  
Author(s):  
Wissem Elkhal Letaief ◽  
Aroua Fathallah ◽  
Tarek Hassine ◽  
Fehmi Gamaoun
Keyword(s):  
Finite Element ◽  
Coupled Model ◽  
Element Model ◽  
Orthodontic Wires ◽  
Niti Wire ◽  
Element Analysis ◽  
Finite Element Software ◽  
Orthodontic Wire ◽  
Niti Shape Memory Alloys

Thanks to its greater flexibility and biocompatibility with human tissue, superelastic NiTi alloys have taken an important part in the market of orthodontic wires. However, wire fractures and superelasticity losses are notified after a few months from being fixed in the teeth. This behavior is due to the hydrogen presence in the oral cavity, which brittles the NiTi arch wire. In this article, a diffusion-mechanical coupled model is presented while considering the hydrogen influences on the NiTi superelasticity. The model is integrated in ABAQUS finite element software via a UMAT subroutine. Additionally, a finite element model of a deflected orthodontic NiTi wire within three teeth brackets is simulated in the presence of hydrogen. The numerical results demonstrate that the force applied to the tooth drops with respect to the increase in the hydrogen amount. This behavior is attributed to the expansion of the NiTi structure after absorbing hydrogen. In addition, it is shown that hydrogen induces a loss of superelasticity. Hence, it attenuates the role of the orthodontic wire on the correction tooth malposition.

scholarly journals Spatial Uncertainty Modeling for Surface Roughness of Additively Manufactured Microstructures via Image Segmentation

2019 ◽  
Vol 9 (6) ◽  
pp. 1093 ◽  
Author(s):  
Namjung Kim ◽  
Chen Yang ◽  
Howon Lee ◽  
Narayana Aluru
Keyword(s):  
Finite Element ◽  
Image Segmentation ◽  
Compressive Loading ◽  
Dimensional Accuracy ◽  
Element Model ◽  
Spatial Uncertainty ◽  
Von Mises Stress ◽  
Modeling Framework ◽  
Element Analysis ◽  
Manufacturing Method

Despite recent advances in additive manufacturing (AM) that shifts the paradigm of modern manufacturing by its fast, flexible, and affordable manufacturing method, the achievement of high-dimensional accuracy in AM to ensure product consistency and reliability is still an unmet challenge. This study suggests a general method to establish a mathematical spatial uncertainty model based on the measured geometry of AM microstructures. Spatial uncertainty is specified as the deviation between the planned and the actual AM geometries of a model structure, high-aspect-ratio struts. The detailed steps of quantifying spatial uncertainties in the AM geometry are as follows: (1) image segmentation to extract the sidewall profiles of AM geometry; (2) variability-based sampling; (3) Gaussian process modeling for spatial uncertainty. The modeled spatial uncertainty is superimposed in the CAD geometry and finite element analysis is performed to quantify its effect on the mechanical behavior of AM struts with different printing angles under compressive loading conditions. The results indicate that the stiffness of AM struts with spatial uncertainty is reduced to 70% of the stiffness of CAD geometry and the maximum von Mises stress under compressive loading is significantly increased by the spatial uncertainties. The proposed modeling framework enables the high fidelity of computer-based predictive tools by seamlessly incorporating spatial uncertainties from digital images of AM parts into a traditional finite element model. It can also be applied to parts produced by other manufacturing processes as well as other AM techniques.

Analysis on Oil Extraction Progressing Cavity Pump Three-Dimensional Finite Element Model

2014 ◽  
Vol 644-650 ◽  
pp. 670-673
Author(s):  
Guo You Han ◽  
Ming Qi Wang ◽  
Yu Hou ◽  
Qiang Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Analysis Model ◽  
Element Analysis

The finite element analysis of PCP involves three nonlinear of geometry, material and contact, and the load of PCP is diversity, leading to it difficult to establish the finite element model and calculate by finite method. This article takes GLB120-27 as an example, to establish 3D solid model of PCP by using SolidWorks; to determine M-R model constant of stator rubber by using the data of uniaxial tensile test: to separate the seal band from the stator chamber by using Boolean operation and set up contact pairs, to achieve the correct simulation of stator chamber fluid pressure; to correctly simulate the interference fit between stator and rotor through setting correlation parameters; to establish 3D finite element analysis model and verify the correctness by using the experiment data of hydraulic characteristics of PCP.

scholarly journals Finite element analysis of knee articular cartilage

2021 ◽  
Author(s):  
Randall Heydon
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Knee Flexion ◽  
Compressive Loading ◽  
Material Model ◽  
Element Model ◽  
Cartilage Thickness ◽  
Finite Element Models ◽  
Element Analysis ◽  
Load Response

The knee joint is often subjected to high loads, which can lead to injury and osteoarthritis. To better understand its behaviour, a finite element model of the joint was created. A hyperelastic material model was created to represent articular cartilage. A six parameter Ogden curve was fiitted against experimental stress-stretch data of cartilage. This material was applied to two different finite element models of the knee created from anatomical slice images. The complete models were validated against data from experiments performed on whole knees. Under compressive loading, the deflection of the model joints were found to be within one-half of a standard deviation of the experimental data. One model was tested in alternate configurations; its response was found to be strongly related to cartilage thickness and knee flexion. Therefore, it is concluded that this cartilage material model can be used to accurately predict the load response of knees.

scholarly journals Easing the Strain

2000 ◽  
Vol 122 (09) ◽  
pp. 90-93
Author(s):  
Glen Hartung
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Dynamic Strain ◽  
Structural Components ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Vehicle Cabin ◽  
The Finite Element Analysis ◽  
The Finite Element Model ◽  
Principal Strains

This article focuses on the finite element analysis (FEA) that is a key ingredient in keeping a popular theme park ride up and running. Long before the ride entered service, Universal called in GLENCO Engineering Inc., to perform finite element modeling and analysis in order to evaluate the primary structural components of the Spider-Man ride vehicle cabin. The FEA initiated to increase the stiffness of the cabin floor also identified a location where the peak strains were higher than the values determined in the hand calculations and associated strain gauge testing. The FEA of the Spider-Man cabin structure significantly improved the design of the composite floor. Strains measured at locations selected without the benefit of FEA produced a misleading assessment of the design in its first prototype. FEA, however, identified peak strains at a location and direction that were not intuitively obvious to the engineers. The results were confirmed with dynamic strain measurements—verifying not only magnitude but also directions of the principal strains. The finite element model was a valuable tool that enabled the floor design to be precisely refined in one of the iterations.

Finite Element Analysis for Lateral Resistance Performance of New Precast Concrete Shear Wall

2011 ◽  
Vol 243-249 ◽  
pp. 124-129
Author(s):  
Zhang Feng Zhu ◽  
Zheng Xing Guo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Precast Concrete ◽  
Element Model ◽  
Shear Wall ◽  
Element Analysis ◽  
Lateral Resistance ◽  
Resistance Performance

According to arrangements of local cast-in-situ regions, new precast concrete shear wall (NPC wall) has various types including integrally precast component, component with precast concealed columns and local region of wall by casting in situ, component with precast one end concealed column and the other end by casting in situ and component with all cast-in-situ concealed columns. By finite element analysis for four types of NPC wall and comparing with monolithic cast-in-situ finite element model, the lateral resistance performance of each type of NPC wall were discussed. Compared with cast-in-situ finite element model, NPC wall has rather different lateral resistant mechanism, the load-displacement curves are obviously different, and the horizontal and vertical connections decrease the strength and stiffness. The reasonable arrangement of local cast-in-situ regions can effectively improve the lateral resistance performance of NPC wall. The model composed of all cast-in-situ concealed columns, which has similar lateral resistant performance to cast-in-situ model and shows reasonable load mechanism, should be recommended. Meanwhile, the model consisting of precast concealed column and local cast-in-situ region of wall should be avoided for its poor performance.

scholarly journals Finite Element Analysis of Cornea and Lid Wiper During Blink, With and Without Contact Lens

2020 ◽  
Author(s):  
Vivek R ◽  
Meenatchi S ◽  
Rinu Thomas ◽  
Ramesh Ve ◽  
Raghuvir Pai ◽  
...  
Keyword(s):  
Finite Element ◽  
Contact Lens ◽  
Element Model ◽  
Biomechanical Properties ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Biomechanical Changes ◽  
Von Mises

Abstract Contact Lens-related Discomfort (CLD) is one of the major problems in about 50% of contact lens users. It is a symptom of a variety of conditions such as Lid Wiper Epitheliopathy (LWE), Superior Epithelial Arcuate Lesion (SEAL), Limbal Stem Cell Deficiency (LSCD), Superior Limbic Keratoconjunctivitis (SLK) and dry eye disease; which affect the quality of life. Hence, it is essential to investigate the underlying cause of CLD. During a blink, the under surface of the eyelid tends to interact with the cornea and the conjunctiva. The presence of a contact lens can add to the biomechanical changes on these surfaces. To estimate these changes with and without a contact lens, a Finite Element Model (FEM) of the eyelid wiper, eyeball and contact lens was developed using COMSOL Multiphysics®. Biomechanical properties such as von Mises stress and displacement were calculated. Our study concluded that large stress formed in the lid wiper could be the reason for the occurrence of LWE and SLK without contact lens in the eye. When the contact lens was in situ, large stress was found in the superior 1.3mm of the cornea which could be responsible for the development of SEAL and superior LSCD.

scholarly journals Finite element analysis of knee articular cartilage

2021 ◽  
Author(s):  
Randall Heydon
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Knee Flexion ◽  
Compressive Loading ◽  
Material Model ◽  
Element Model ◽  
Cartilage Thickness ◽  
Finite Element Models ◽  
Element Analysis ◽  
Load Response

The knee joint is often subjected to high loads, which can lead to injury and osteoarthritis. To better understand its behaviour, a finite element model of the joint was created. A hyperelastic material model was created to represent articular cartilage. A six parameter Ogden curve was fiitted against experimental stress-stretch data of cartilage. This material was applied to two different finite element models of the knee created from anatomical slice images. The complete models were validated against data from experiments performed on whole knees. Under compressive loading, the deflection of the model joints were found to be within one-half of a standard deviation of the experimental data. One model was tested in alternate configurations; its response was found to be strongly related to cartilage thickness and knee flexion. Therefore, it is concluded that this cartilage material model can be used to accurately predict the load response of knees.

Finite Element Analysis of a Composite Bulkhead Structure

2007 ◽  
Vol 348-349 ◽  
pp. 553-556 ◽  
Author(s):  
A. Apicella ◽  
Enrico Armentani ◽  
Renato Esposito ◽  
Michele Pirozzi
Keyword(s):  
Finite Element ◽  
Structural Strength ◽  
Element Model ◽  
Structural Safety ◽  
Strain Gauges ◽  
Structural Components ◽  
Element Analysis ◽  
Pressure Load ◽  
Composite Layers ◽  
Aircraft Performance

Reducing structural weight is one of the major ways to improve aircraft performance. Lighter and/or stronger materials allow greater range and speed and may also contribute to reducing operational costs. Nowadays composite materials are widely used in “primary” structural components such as fuselage, for which contrasting requirements like lightness and structural strength are required, so particular attention is necessary during its design. In this paper a composite front bulkhead, subjected to ultimate pressure load, was examined. The front bulkhead is made of a composite skin, stiffened with seven vertical stiffeners linked through metallic fittings; the whole system is joined to the fuselage by rivets. A Finite Element model was established: the used elements were four nodes shells, simulating composite layers, and two nodes bar elements, simulating rivets; the structure was clamped and a pressure load was applied to the skin. A linear static stress analysis was performed to calculate strains in particular points in which strain gauges or rosettes are placed: the numerical results, compared with experimental ones, show a good degree of correlation. Stress calculations were performed in order to verify the front and rear bulkhead structural safety.

scholarly journals Assessment of the role of sutures in a lizard skull: a computer modelling study

2008 ◽  
Vol 276 (1654) ◽  
pp. 39-46 ◽  
Author(s):  
Mehran Moazen ◽  
Neil Curtis ◽  
Paul O'Higgins ◽  
Marc E.H Jones ◽  
Susan E Evans ◽  
...  
Keyword(s):  
Finite Element ◽  
Bone Growth ◽  
Computer Modelling ◽  
Computational Modelling ◽  
Complex Loading ◽  
Element Model ◽  
Element Analysis ◽  
Modelling Studies ◽  
And Function

Sutures form an integral part of the functioning skull, but their role has long been debated among vertebrate morphologists and palaeontologists. Furthermore, the relationship between typical skull sutures, and those involved in cranial kinesis, is poorly understood. In a series of computational modelling studies, complex loading conditions obtained through multibody dynamics analysis were imposed on a finite element model of the skull of Uromastyx hardwickii , an akinetic herbivorous lizard. A finite element analysis (FEA) of a skull with no sutures revealed higher patterns of strain in regions where cranial sutures are located in the skull. From these findings, FEAs were performed on skulls with sutures (individual and groups of sutures) to investigate their role and function more thoroughly. Our results showed that individual sutures relieved strain locally, but only at the expense of elevated strain in other regions of the skull. These findings provide an insight into the behaviour of sutures and show how they are adapted to work together to distribute strain around the skull. Premature fusion of one suture could therefore lead to increased abnormal loading on other regions of the skull causing irregular bone growth and deformities. This detailed investigation also revealed that the frontal–parietal suture of the Uromastyx skull played a substantial role in relieving strain compared with the other sutures. This raises questions about the original role of mesokinesis in squamate evolution.

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