Practical Introduction to Non-Linear Finite Element Analysis 2-day training course on 26th & 27th September This non-linear Finite Element course is intended for delegates interested in learning how finite elements are used to analyse advanced non-linear problems, difficulties encountered in modelling real-life applications and guidelines for using non-linear finite element technology. The objectives of this Finite Element course are: To provide delegates with an introduction to the funda
Finite element analysis can provide insight to the complex mechanical behavior of natural and restored craniofacial structures affected by 3-D stress fields, which are still very difficult to assess otherwise. Even though the distribution of forces in peri-implant bone has been investigated by finite element analysis in several studies,33,34 a comparison of 2-dimensional finite element analyses and 3D-FE analyses in one study showed that only 3D-FE analysis could realistically simulate the stress pattern in space.35 Finite element modeling, like all in vitro studies that use model systems, has advantages and limitations. The 3-D model in this study was designed with precise geometry of the implant and the anatomy along with appropriate element type and count; however, certain assumptions were made in material properties and applied boundary conditions because of a lack of data and technology. Besides, technical difficulty in adjusting the degree of osseointegration led to the assumption of 100% ...
finite element analysis Free Download - static finite element analysis, finite element analysis for geology, finite element analysis dll library and more.
1] W.M. Bayliss, On the local reaction of the arterial wall to changes of internal pressure. J. Physiol. London 28 (1902) 220-231. [2] J. Berntsen, T.O. Espelid and A. Genz, Algorithm 698: DCUHRE: An adaptive multidimensional integration routine for a vector of integrals. ACM Trans. Math. Softw. 17 (1991) 452-456. , Zbl 0900.65053 [3] P.H.M. Bovendeerd, T. Arts, J.M. Huyghe, D.H. Van Campen and R.S. Reneman, Dependance of local left ventricular wall mechanics on myocardial fiber orientation: a model study. J. Biomech. 25 (1992) 1129-1140. [4] P.G. Ciarlet, The finite element method for elliptic problems, Vol. 4 of Studies in Mathematics and its Applications. North-Holland, Amsterdam-New York (1980). , MR 608971 , Zbl 0511.65078 [5] K.D. Costa, P.J. Hunter, J.S. Wayne, L.K. Waldman, J.M. Guccione and A.D. Mcculloch, A three-dimensional finite element method for large elastic deformations of ventricular myocardium: Part I. Cylindrical and spherical polar coordinates. ASME J. Biomech. Eng. 118 ...
Practical Introduction to Finite Element Analysis 3-Day Training Course An opportunity to ensure that your organization gets maximum benefit from using Finit Element Analysis. FEA has become widely used and universally accepted in many industry sectors. Finite Element Analysis is a powerful technique, able to produce solutions to challenging structural analysis problems. The technology and computational efficiency of the method, together with the rapid increases in computer processi
Lateral mass screw fixation (LSF) techniques have been widely used for reconstructing and stabilizing the cervical spine; however, complications may result depending on the choice of surgeon. There are only a few reports related to LSF applications, even though fracture fixation has become a severe complication. This study establishes the three-dimensional finite element model of the lower cervical spine, and compares the stress distribution of the four LSF techniques (Magerl, Roy-Camille, Anderson, and An), following laminectomy -- to explore the risks of rupture after fixation. CT scans were performed on a healthy adult female volunteer, and Digital imaging and communication in medicine (Dicom) data was obtained. Mimics 10.01, Geomagic Studio 12.0, Solidworks 2012, HyperMesh 10.1 and Abaqus 6.12 software programs were used to establish the intact model of the lower cervical spines (C3-C7), a postoperative model after laminectomy, and a reconstructive model after applying the LSF techniques. A
Based on the micropolar elasticity theory, a size-dependent rectangular element is proposed in this article to investigate the nonlinear mechanical behavior of plates. To this end, a novel three-dimensional formulation for the micropolar theory with the capability of being used easily in the finite element approach is developed first. Afterward, in order to study the micropolar plates, the obtained general formulation is reduced to that based on the Mindlin plate theory. Accordingly, a rectangular plate element is developed in which the displacements and microrotations are estimated by quadratic shape functions. To show the efficiency of the developed element, it is utilized to address the nonlinear bending problem of micropolar plates with different types of boundary conditions. It is revealed that the present finite element formulation can be efficiently employed for the nonlinear modeling of small-scale plates by considering the micropolar effects.. ...
A transient non-linear finite element (FE) model is developed in this paper to calculate the natural frequencies of a high-speed beehive spring and simulate its dynamic responses at different engine speeds, with consideration of material damping, internal vibration and coil collision. A 3D scanning technique is used to obtain an accurate geometry of the spring model for the simulation. To validate the FE model, a conventional analytical model with varying stiffness is also developed for the same spring. By comparing the results of both models with the experimental results of engine head tests, it is shown that the FE model can successfully simulate the dynamic responses of the spring under different speeds. Especially, the FE model can predict the erratic force spikes of the spring at high testing speeds, which cannot be predicted by the conventional analytical model. Based on the analysis, the dynamic deformation mechanisms of the high-speed beehive spring are summarised and discussed.. ...
Abductor weakness, and the resulting Trendelenburg gait, after total hip arthroplasty is believed to be associated with a poor long-term outcome. We have constructed a two-dimensional finite element analysis using load cases to mimic this abductor weakness. The finite element analysis demonstrates slightly increased stresses, particularly at the bone-cement interface in the DeLee-Charnley zone I, which does not seem sufficient to explain the adverse effect of abductor weakness. Laffaiblissement des muscles abducteurs et la démarche qui en résulte après le remplacement de la hanche par prothèse, peut être associé avec un résultat médiocre à long terme. Nous avons réalisé une étude par éléments finis à deux dimensions avec des situations imitant cette faiblesse des muscles abducteurs. Cette analyse montre une augmentation légère des contraintes particulièrement à linterface os-ciment dans la zone I de DeLee et Charnley. Ceci ne semble pas suffisant pour expliquer les effets
Introduction: Cryo-imaging is an ex vivo vascular imaging modality that acquires serial 2D fluorescence and bright-field images at 5µm increments without sacrifice to tissue morphology. These features make cryo-imaging an attractive approach for rendering high-resolution 3D volumes that serve as a basis for finite element analysis (FEA) studies of plaque rupture. The current study utilizes images extracted from cryo imaging to render a 3D finite element model of a human coronary vessel to determine the stress and strain fields throughout an atherosclerotic plaque.. Methods: Fresh frozen specimens were sectioned and imaged. Nearly 630 image slices were processed and segmented using the specialized image processing software, ScanIP. Segmented regions included the fibrous cap, calcium, lipid, and the vessel wall. A 3D volume of the coronary vessel was rendered. FEA was performed under linear elastic conditions where material behavior was defined by two constants, Youngs modulus and Poissons ...
Unstable pelvic fracture represents a severe injury associated with high morbidity and mortality. In the past, several types of fixators were used to treat this unstable fracture, including external fixators, plates, sacral bars, iliosacral screws, and pre-tensed curved bar. However, the biomechanical performances of the above fixation techniques were mainly evaluated according to the outcomes of clinical applications, and only one of the fixation techniques was selected and evaluated. To our knowledge, there were few studies to analyze and compare the biomechanical performances of different pelvic fixation techniques. In addition, the past studies had investigated one of the fixation techniques by using finite element methods. However, there has been no study that investigated the biomechanical performances of the fixation techniques by using 3D nonlinear finite element models of spine-pelvis-femur complex. Thus, the purpose of this study was to analyze and investigate the biomechanical ...
TY - JOUR. T1 - Dynamic finite element analysis of the human maxillary incisor under impact loading in various directions. AU - Huang, Haw Ming. AU - Ou, Keng Liang. AU - Wang, Wei Nang. AU - Chiu, Wen Ta. AU - Lin, Che Tong. AU - Lee, Sheng Yang. PY - 2005/10. Y1 - 2005/10. N2 - The aim of this study was to investigate fracture patterns occurring when a human upper central incisor is subjected to impact loadings at various angles. A two-dimensional finite element (FE) model of the maxillary incisor and surrounding tissues was established. The structural damping factor for the tooth was then calculated and assigned to the model. Dynamic FE analysis was performed to stimulate the associated impacts. Time-dependent traumatic forces at 0°, 45°, and 90° labially to the long axis of the tooth were applied to the model. Von Misess equivalent stress contours within the FE models were calculated. Our results indicated that tooth damping lagged behind peak stress by 0.05 ms. In addition, we found ...
DOI: 10.11607/jomi.4179 Purpose: Since bacterial leakage along the implant-abutment interface may be responsible for peri-implant infections, a realistic estimation of the interface gap width during function is important for risk assessment. The purpose of this study was to compare two methods for investigating microgap formation in a loaded dental implant, namely, microcomputed tomography (micro-CT) and three-dimensional (3D) nonlinear finite element analysis (FEA); additionally, stresses to be expected during loading were also evaluated by FEA. Materials and Methods: An implant-abutment complex was inspected for microgaps between the abutment and implant in a micro-CT scanner under an oblique load of 200 N. A numerical model of the situation was constructed; boundary conditions and external load were defined according to the experiment. The model was refined stepwise until its load-displacement behavior corresponded sufficiently to data from previous load experiments. FEA of the final, ...
The aim was to evaluate the influence on the stress distribution patterns in and the magnitude of stresses on fixed partial dentures (FPDs) under different anatomic and design conditions. Three-dimensional finite element models of posterior 3-unit all-ceramic FPDs were created with and without periodontal ligaments, with different radii of curvature at the embrasure area, and in a curve shape with a periodontal ligament. The model with a periodontal ligament showed 40% higher stress values compared to the no-ligament model. A smaller radius of curvature resulted in 20% to 40% higher stress values. The curved model increased stress values at the distal connector by 65% compared to the straight model. Support by teeth, occlusal curvature, and a small radius of curvature at the embrasure area negatively affect stress distribution patterns in the connector area of all-ceramic FPDs.. ...
In this work, we consider elastic wave propagation in fractured media. The mathematical model is described by the Helmholtz problem related to wave propagation with specific interface conditions (Linear Slip Model, LSM) on the fracture in the frequency domain. For the numerical solution, we construct a fine grid that resolves all fracture interfaces on the grid level and construct approximation using a finite element method. We use a discontinuous Galerkin method for the approximation by space that helps to weakly impose interface conditions on fractures. Such approximation leads to a large system of equations and is computationally expensive. In this work, we construct a coarse grid approximation for an effective solution using the Generalized Multiscale Finite Element Method (GMsFEM). We construct and compare two types of the multiscale methods—Continuous Galerkin Generalized Multiscale Finite Element Method (CG-GMsFEM) and Discontinuous Galerkin Generalized Multiscale Finite Element Method (DG
In the present work, a three-dimensional, dynamic and non-linear finite element to simulate thermoelectric behavior under a hyperbolic heat conduction model is presented. The transport equations, which couple electric and thermal energies by the Seebeck, Peltier and Thomson effects, are analytically obtained through extended non-equilibrium thermodynamics, since the local equilibrium hypothesis is not valid under the hyperbolic model. In addition, unidimensional analytical solutions are obtained to validate the finite element formulation. Numerically, isoparametric eight-node elements with two degrees of freedom (voltage and temperature) per node are used. Non-linearities due to the temperature-dependence on the transport properties and the Joule effects are addressed with the Newton-Raphson algorithm. For the dynamic problem, HHT and Newmark-ß algorithms are compared to obtain accurate results, since numerical oscillations (Gibbs phenomena) are present when the initial boundary conditions are ...
Finite element analysis (FEA) is a computer simulation technique used in engineering analysis. It uses a numerical technique called the finite element method (FEM) to solve partial differential equations. There are many finite element software packages, both free and proprietary. Development of the finite element method in structural mechanics is usually based on an energy principle such as the virtual work principle or the minimum total potential energy principle. * ...
Finite Element Method (FEM) is a numerical technique of obtaining solutions to boundary value problems. The practical application of Finite Element Method is called as Finite Element Analysis (FEA). FEA is the computational tool for performing engineering analysis. Biomechanical analysis involves dealing with the mechanical aspects of the biological systems. FEM techniques can be used to study the engineering analysis of different biological systems. Femur bone is the longest and strongest bone of the human body. It undergoes mostly compressive loading. It exhibits anisotropy, indicating that the strength is different in different directions when a force is applied. It is hyperelastic in nature. It has two anatomical structures namely cortical bone tissue and cancellous bone tissue. The cortical is dense and tightly packed. The cancellous is porous. Cortical section is superior in mechanical properties compared to cancellous section. Cortical and cancellous are formed with collagen fibers. Upon ...
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Finite Element Model of Cornea Deformation - Abstract. Cornea surgeons have observed that changes in cornea curvature can follow cataract surgery and cause astigmatism. The placement of surgical incisions has been shown to influence these curvature changes. Though empirical data has been collected about this phenomenon, a biomechanical model has not been employed in predicting post-surgical outcomes. This work implemented an incised finite element model of the eye to investigate factors influencing corneal shape after surgery. In particular, the effects of eye muscle forces and intra-ocular pressure were simulated. Cornea shape change was computed via finite element analysis, and the resulting change in cornea curvature was measured by fitting quadratic curves to the horizontal and vertical meridians of the cornea. Results suggest that these two sources of deforming force counteract each other and contribute to astigmatism in perpendicular directions.
Since the middle of the last century, computing power has increased sufficiently that the direct numerical approximation of Maxwells equations is now an increasingly important tool in science and engineering. Parallel to the increasing use of numerical methods in computational electromagnetism, there has also been considerable progress in the mathematical understanding of the properties of Maxwells equations relevant to numerical analysis. The aim of this book is to provide an up-to-date and sound theoretical foundation for finite element methods in computational electromagnetism. The emphasis is on finite element methods for scattering problems that involve the solution of Maxwells equations on infinite domains. Suitable variational formulations are developed and justified mathematically. An error analysis of edge finite element methods that are particularly well suited to Maxwells equations is the main focus of the book. The analysis involves a complete justification of the discrete de Rham
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DOI: 10.11607/jomi.3234 Purpose: Elevated bite forces and reduced bone densities and dimensions associated with posterior regions of the maxilla cause relatively high failure rates when short dental implants are placed to substitute missing teeth. This study uses the finite element method to evaluate four distinctly different short implant designs (Bicon, Neodent, Nobel Biocare, and Straumann) for their influences on the von Mises stress characteristics within the posterior maxilla. Materials and Methods: Finite element models of the supporting bone and tooth crowns are developed based on computed tomography data, and implant geometries are obtained from manufacturers catalogs. The finite element models are meshed using three-dimensional hexahedral and wedge-shaped brick elements. Assumptions made in the analyses are: linear elastic material properties for bone, 50% osseointegration between bone and implant, and crown height implant length ratio of 2:1. Results: Bicon s neck indentation produced ...
TY - GEN. T1 - Non-Linear Finite Element Modelling of Hydraulic Driven Multibody System. AU - Ylinen, Antti. AU - Mäkinen, Jari. AU - Marjamäki, Heikki. N1 - /kir12 . ei ut-numeroa 12.10.2013,br/,Contribution: organisation=mec,FACT1=0.5,br/,Contribution: organisation=rak rtek,FACT2=0.5,br/,Publisher name: Oulun yliopisto. PY - 2012. Y1 - 2012. M3 - Conference contribution. SN - 978-952-62-0006-4. T3 - Finnish Mechanics Days. Suomen Mekaniikkapäivät. SP - 57. EP - 62. BT - Proceedings of the 11th Finnish Mechanics Days. XI Suomen Mekaniikkapäivät, Oulun yliopisto 29.-30.11.2012. A2 - Hannu, Koivurova. A2 - Mikko, Malaska. PB - Oulun yliopisto. CY - Oulu. ER - ...
While this module provides only a small part of the Abaqus input file format, it suffices for most standard jobs. While we continue to expand the interface, depending on our own necessities or when asked by third parties, we do not intend to make this into a full implementation of the Abaqus input specification. If you urgently need some missing function, there is always the possibility to edit the resulting text file or to import it into the Abaqus environment for further processing.. The module provides two levels of functionality: on the lowest level, there are functions that just generate a part of an Abaqus input file, conforming to the Abaqus™ Keywords manual.. Then there are higher level functions that read data from the property module and write them to the Abaqus input file and some data classes to organize all the data involved with the finite element model.. ...
The backlite molding squeak noise is caused by the stick-slip type of friction between the window molding and the body panel. To predict if the molding would squeak a finite element analysis technique which uses the nonlinear explicit code LS-DYNA3D has been developed. The three dimensional finite element simulation technique is based on the threshold displacement velocity spectrum and the relative movement of the window glass with respect to the body panel. Comparisons between FEA analysis and tests are also presented in this paper ...
Learn how to perform finite element analysis (FEA) in MATLAB. Resources include videos, examples, and documentation covering finite element analysis and other topics.
Isherwood is able to leverage its experience to aid in Finite Element Analysis on sensitive projects. With our knowledge of soil and rock mechanics and shoring behaviour, the Finite Element Analysis is successfully used to identify risks to sensitive structures due to excavation and predict the magnitude of deformation of the shoring, soil, and surrounding buildings.. ...
Lecture 22 - Advanced Finite Elements Analysis This video is part of Lecture Series on Advanced Finite Elements Analysis by P...
Lecture 5 - Advanced Finite Elements Analysis This video is part of Lecture Series on Advanced Finite Elements Analysis by P...
In the present paper, applicability of the modified fixed grid finite element method in solution of three dimensional elasticity problems of functionally graded materials is investigated. In the non-boundary-fitted meshes, the elements are not conforming to the domain boundaries and the boundary nodes which are used in the traditional finite element method for the application of boundary conditions no longer exist. Therefore, special techniques are needed for computation of the stiffness matrix of boundary intersecting elements and application of boundary conditions.The stiffness matrix of boundary intersecting elements are calculated via integration of strain energy over the internal parts of these elements. Essential boundary conditions are applied using penalty function method. To examine the effectiveness of the proposed method, some numerical examples are solved and results are compared with those obtained using the standard finite element method.
An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on ...
Finite element analysis is a method for solving partial differential equations (PDEs). There are many other methods for solving PDEs with different features, but finite element methods are attractive both because they work well with complex geometries and because they are relatively simple to implement and analyze. I use existing codes where appropriate, but have released several finite element software packages for simulating problems from MEMS design and analysis of human bone.. ...
There are several types of tenodesis reconstruction designed for subtalar instability. However, no comprehensive comparison has been conducted among these procedures in terms of their correcting power so far. The objective of this study is to evaluate the biomechanical behaviors of 5 representative procedures through finite element analysis. Finite element models were established and validated based on one of our previous studies. The Pisani interosseous talocalcaneal ligament (ITCL) reconstruction, Schon cervical ligament (CL) reconstruction and Choisne calcaneofibular ligament (CFL) reconstruction were compared on the model with the CFL, ITCL and CL sectioned. The Schon triligamentous reconstruction and Mann triligamentous reconstruction were compared on the model with the CFL, ITCL and CL, as well as the ATFL sectioned. The inversion and external/internal rotation were quantified at different ankle positions based on the rotational moment. Then, the stress in ligaments and reconstructed grafts and
View Notes - MIT2_092F09_lec05 from MECHANICAL 2.092 at MIT. 2.092/2.093 - Finite Element Analysis of Solids & Fluids I Fall 09 Lecture 5- The Finite Element Formulation Prof. K. J. Bathe
We use a 2 dimensional finite element model with heterogeneous elastic strengths in continental areas to model the regional stress field orientation and relative magnitudes in and around India for 33 Ma, 20 Ma and the present day. The large-scale geological structure of India is embedded in our model by using published outlines of cratons, fold belts and basins, associated with estimates of their relative strengths, enabling the modelling of stress field deflections along interfaces between relatively strong and weak tectonic elements through time. … Read more…. ...
When we consider the rehabilitation of patients with the mandibular implant supported over denture, the influence of the implant number and the cantilever design on the stress distribution on the bone needs to be assessed precisely. Purpose: The purpose of the simulation study was to compare the biomechanical behavior of the two implant supported over denture design with the All-On-Four Concept using the three dimensional finite element method thereby evaluating the Von Misses stresses induced on the implant under different loading simulations. Materials & Method: Three dimensional models representing mandible restored with two implant supported prosthesis was compared with the models that were restored based on the All-On-Four concept. The models were then subjected to four different loading simulations (full mouth biting, canine disclusion, load on cantilever, and load in the absence of cantilever). The maximum von Mises stresses were localized and quantified for comparison.1 Results: Among
Learn about finite element analysis (FEA), how it works and the difference between FEA and the finite element method. Explore the advantages of FEA, its common applications and the principles behind the method and analysis.
To study the effects of different designs in single mandibular molar implant restoration on the stress distribution of implant-bone interface. Methods: Three-dimensional finite element method were used. Results: When wide-diameter implant or two-implant were used to replace single mandibular molar, the stress of implant-bone interface was much lower than that of standard-diameter implant restoration. Comparison between wide-diameter implant and two-implant replacement showed that the former created lower stress. The difference was more obvious under oblique loads. Conclusion: Using wide-diameter implant or two-implant to restore single mandibular molar should be recommended in clinical practice. If adequate bone quantity is provided, using wide-diameter implant should be better.
In the shop floor, cracking issue was noticed during assembly of valve seat and valve guide in the engine cylinder head, especially near the valve seating area. This paper reveals a non- linear finite element methodology to verify the structural integrity of a cylinder head during valve seat and valve guide assembly press-in operation under the maximum material condition, i.e., smallest hole size on cylinder head for valve seat and guide and largest diameter of valve seat and guide. Material and geometrical nonlinearities, and contact are included in this method to replicate the actual seat and guide press-in operation which is being carried out in shop floor. The press-in force required for each valve seat and valve guide assembly is extracted from simulation results to find out the tonnage capacity of pressing machine for cylinder head assembly line. Stress and plastic deformation due to assembly load are the criteria checked against the respective material yield. Further the tolerance such as ...
We use Finite Element solver to calculate atoms position of elliptical shaped island in the box containing up to 100000 atoms. In this approach we describe bonds as pseudoelements and restrict calculations to two types of them: 2-node, which model interaction between 2(1 bond) atoms and 3-node, which model interaction between 3-atoms (2 bonds). Novel mesh generator was developed for creation of the pseudoelements compatible with standard Finite Element routines ...
TY - CONF. T1 - Finite element analysis of the tibial component stem orientation in revision total knee replacement. AU - Rastetter, Benjamin. AU - Wright, Samantha. AU - Gheduzzi, Sabina. AU - Miles, Anthony. AU - Clift, Sally. PY - 2015/9. Y1 - 2015/9. N2 - Background: Finite element (FE) models are frequently used in biomechanics to predict the behaviour of new implant designs.To increase the stability after severe bone loss tibial components with long stems are used in revision total knee replacements(TKR). A clinically reported complication after revision surgery is the occurrence of pain in the stem-end region. The aim ofthis analysis was the development of a validated FE-model of a fully cemented implant and to evaluate the effect of differenttibial stem orientations.Methods: A scanned 4th generation synthetic left tibia (Sawbones) was used to develop the FE-model with a virtually implantedfully cemented tibial component. The 500 N load was applied with medial:lateral compartment ...
Paris, France, and Providence, R.I., USA, May 15, 2007 - Dassault Systèmes (DS) (Nasdaq: DASTY; Euronext Paris: #13065, DSY.PA), a world leader in 3D and Product Lifecycle Management (PLM) solutions, announces the release of Abaqus Version 6.7, its technology-leading finite element analysis (FEA) software suite. Abaqus Version 6.7 introduces a new architecture for high-performance linear dynamics, advanced capabilities for composites simulation and nonlinear materials modeling, a new intuitive and highly customizable user interface for accelerated model building and results visualization, and two new interfaces for bi-directional CAD associativity. SIMULIA is delivering several important enhancements to their Abaqus FEA software that we expect will greatly improve overall productivity at Scania, stated Martin Edberg, head of chassis simulations, Scania CV AB. We are particularly impressed with the new high-performance linear dynamics functionality in Abaqus Version 6.7. The new linear ...
An application of the basic concepts of finite element modeling and analysis to various types of engineering technology problems including structural and machine component analysis, conduction and convection heat-transfer analysis, and fluid mechanics analysis. Selected analytical aspects of finite element analysis are introduced throughout the course without becoming too theoretical. ANSYS computer software is an integral part of the course and is used within the laboratory portion. Prerequisite: ENT 333. 2 Lec. 1 Lab.. Back to top. ...
Cable-stayed bridges can exhibit large amplitude irregular stay cable oscillations under certain conditions of combined traffic flow and rain-wind loads that can pose severe risks to structural integrity. To investigate the mechanisms causing this behavior, a high fidelity nonlinear finite element model of a typical cable-stayed bridge has been developed using LS-DYNA based on the design of the Bill Emerson Memorial Bridge at Cape Girardeau, MO. The model uses over 540,000 finite elements representing 1254 bridge components to fully describe the detailed real geometry of the bridge tower, deck, stay cables, edge girders and floor-beam support girders. Traffic loads on the bridge deck are simulated by a Poisson Distributed Pulse (PDP) stochastic process model involving multi-lane traffic flows of more than 300 vehicles of various axle loads with varying arrival rates. The response data sets generated by the LS-DYNA simulations were then analyzed for chaotic behavior with the software CTBR. This ...
TY - JOUR. T1 - Fast estimation of Colles fracture load of the distal section of the radius by homogenized finite element analysis based on HR-pQCT. AU - Hosseini, H.S.. AU - Dünki, A.. AU - Fabech, J.. AU - Stauber, M.. AU - Vilayphiou, N.. AU - Pahr, D.. AU - Pretterklieber, M.. AU - Wandel, J.. AU - van Rietbergen, B.. AU - Zysset, Ph.K.. PY - 2017/4/1. Y1 - 2017/4/1. N2 - Fractures of the distal section of the radius (Colles fractures) occur earlier in life than other osteoporotic fractures. Therefore, they can be interpreted as a warning signal for later, more deleterious fractures of vertebral bodies or the femoral neck. In the past decade, the advent of HR-pQCT allowed a detailed architectural analysis of the distal radius and an automated but time-consuming estimation of its strength with linear micro-finite element (μFE) analysis. Recently, a second generation of HR-pQCT scanner (XtremeCT II, SCANCO Medical, Switzerland) with a resolution beyond 61 μm became available for even more ...
FRANCO uses two-dimensional finite element theory and applications for mechanical deformation and heat conduction, and determines the temperature distribution from the fuel center to the coolant adjacent to the clad at a position along the fuel rod axis. FRANCO calculates the average temperature of each radial division, the nodal displacement, and strain and stress within the fuel pellet and clad. The principal stresses, which represent maximum and minimum stresses within an element, result from Mohrs circle relationship between normal stresses. FRANCO is capable of predicting the thermo-mechanical behavior in the radial direction of a single fuel rod for both boiling water reactors (BWRs) and pressurized water reactors (PWRs). The cross sectional plane geometry of fuel rod is modeled using three-node constant strain triangular finite elements, and both thermal and mechanical solutions are computed with the same finite element configurations. The local linear heat generation rate is modeled ...
TY - JOUR. T1 - The effect of Bone quality on the initial stability of ankle arthrodesis with internal fixation. A finite element simulation. AU - Alonso-Vazquez, A. AU - Lauge-Pederson, H. AU - Lidgren, L. AU - Taylor, Mark. PY - 2004. Y1 - 2004. M3 - Article. VL - 25. SP - 840. EP - 850. JO - Foot and Ankle International. JF - Foot and Ankle International. SN - 1071-1007. ER - ...
Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics.
The stability of acetabulum reconstructions using reinforcement rings and hooks is important for successful replacement surgery. The objective of this study was to biomechanically determine the effects of the hook on stress and the related micromotions of the acetabular reinforcement ring during the immediate postoperative period. Acetabular reinforcement ring models were developed using a nonlinear, three-dimensional, finite element method. Using a pre-prepared template, we constructed without-hook and bone graft models of varying volumes and material properties. The stress on the inferior margin of the acetabulum was higher in the with-hook model than in the without-hook model, especially with increased bone graft volumes, and the stiffness of the bone graft material was decreased. Relative micromotions in the without-hook model were higher than in the with-hook models. The highest relative micromotion was observed in the model with increased bone graft volume and lower stiffness of bone graft
Objectives: The aim of this study was to analyze mechanical and thermal stresses of hybrid ceramic and lithium disilicate based ceramic of CAD/CAM inlays using 3D Finite element analysis. Material and Methods: A three dimensions finite element model of permanent maxillary premolar designed according to standard anatomy with class II cavity preparation for inlay restored with two different ceramic materials:- 1- Hybrid ceramic (Vita Enamic), 2- Lithium disilicate based ceramic (IPS e.max CAD). Totally six runs were performed on the model as: One loading case for each restorative material was tested in stress analysis; seven points of loading with 140N vertically applied at palatal cusp tip and cusp slop, marginal ridges and central fossa while the models base was fixed as a boundary condition in the two cases. Two thermal analysis cases were performed for each restoration material by applying 5ºC and 55ºC on the crown surface including the restoration surface. Results: The results of all ...
DISCUSSION. The mean fracture resistance results observed in the present study (Table 2) are higher than the mean bite force values reported by Lyons15 (1990) for canine teeth of approximately 22 kgf. In contrast, patients with bruxism presented a bite force of almost 26 kgf and the maximum bite force in the canine region ranged from 32 to 35 kgf.. In a study using the finite element method, Joshi, et al.13 (2001) observed that among all factors that interfere with the stress distribution pattern, post diameter and geometry contribute less to an increase or decrease of stresses in the tooth. In the present study, geometry was found to modify the stress distribution pattern (Figure 7), as demonstrated by Lewgoy, et al.14 (2003).. Posts do not reinforce debilitated teeth9, a fact that might be explained mechanically1,17. Cementation of a post during root treatment alters the load distribution pattern along its axis. The crack starts in the region of highest stress concentration (compressive or ...
In the total hip prosthesis, according to different positions of the patient, there are a variety of loads acting on femoral head which generate stress concentration in the cement called polymethylmethacrylat (PMMA) and consequently in the interfaces stem/cement/bone. This load transfer can provoke loosening of the implant from the femoral bone. This paper focused on optimal stress distribution in the total hip prosthesis and devoted to the development of a redesigned prosthesis type in order to minimize stress concentration in the cement. This study investigated the effect of elastomeric stress barrier incorporated between the stem and femoral head using 3D-finite element analysis. This proposed implant provoked lower load transfer in the cement due to the elastomeric effect as stress absorber. However, the proposed model provided an acceptable solution for load transfer reduction to the cement. This investigation permitted to increase the service life of the total hip prosthesis avoiding the ...
A novel approach combining the atomic force microscopy probing of nacre biopolymer strand and the inverse finite element analysis has been used to directly measure the elastic modulus of nacre biopolymer matrix. An elastic modulus of 11 ± 3 GPa was determined for the first time from the direct measurement of the nacre biopolymer matrix. This property is essential for a fundamental understanding of the roles that the biopolymer matrix plays in nacres strengthening and toughening, and provides guidelines in selecting engineering polymers for biomimetic materials design and fabrication. Such coupled experimental and modeling techniques should find more applications in studying the mechanical behavior of biological materials.
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This paper gives a bibliographical review of the finite element methods applied to the analysis and simulation of quenching and other heat treatment processes. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subjects that were published between 1976 and 2001. The following topics are included: quenching - quenching process in general, heat transfer and thermomechanical modelling, residual stresses in quenching, and other topics, hardening, annealing, tempering, and carburizing and nitriding. Three hundred and fifty references are listed. © 2003 Elsevier Science B.V. All rights reserved.. ...
In vivo rodent tail models are becoming more widely used for exploring the role of mechanical loading on the initiation and progression of intervertebral disc degeneration. Historically, finite element models (FEMs) have been useful for predicting disc mechanics in humans. However, differences in geometry and tissue properties may limit the predictive utility of these models for rodent discs. Clearly, models that are specific for rodent tail discs and accurately simulate the discs transient mechanical behavior would serve as important tools for clarifying disc mechanics in these animal models. An FEM was developed based on the structure, geometry, and scale of the mouse tail disc. Importantly, two sources of time-dependent mechanical behavior were incorporated: viscoelasticity of the matrix, and fluid permeation. In addition, a novel strain-dependent swelling pressure was implemented through the introduction of a dilatational stress in nuclear elements. The model was then validated against data ...
Purpose: To determine the favorable therapeutic position for Chinese manipulation in treating lumbar disc herniation. Methods: We developed a three-dimensional finite element model of L3-5 for the normal spine, along with a mild degeneration and a moderate degeneration model, and carried out a comparative study between the manipulation with lateral position and that with sitting position. The displacement and stress distribution in the intervertebral disc of L4 were investigated. Results: A displacement and stress directing forwards concentrated on the left rear of L4 disc were found in the three models under the two manipulations. The values of displacement and stress under the manipulations with lateral position are larger than those with sitting position in the three models. Conclusion: Lateral position has a better biomechanical effect than sitting position in treating lumbar disc herniation.. ...
Purpose: : Schlemms canal endothelial (SCE) cells are exposed to a basal-to-apical pressure difference that causes the cells to deform. We used finite element models and measured mechanical properties to determine the maximum pressure drop that SCE cells can support. Methods: : Finite element models of typical SCE cells were developed using scanning (SEM) and transmission (TEM) electron micrographs. Based on SEM images of the inner wall endothelium from 8 human eyes, 3 typical cellular footprints were chosen. Thickness profiles were measured from TEM images of 10 inner wall cells from 5 human eyes. Cell models were constructed using the 3 typical footprints and two possible thicknesses: (i) the average thickness of the cells; and (ii) the maximum thickness, the latter corresponding to a very strong cell (conservative case). Cells were assumed to be attached only at their periphery.A commercial finite element package ABAQUS was then used to compute: (i) cellular deformations for different ...
TY - JOUR. T1 - Probabilistic evaluation of the material properties of the in vivo subject-specific articular surface using a computational model. AU - Kang, Kyoung Tak. AU - Kim, Sung Hwan. AU - Son, Juhyun. AU - Lee, Young Han. AU - Kim, Shinil. AU - Chun, Heoung Jae. N1 - Publisher Copyright: © 2016 Wiley Periodicals, Inc.. PY - 2017/8. Y1 - 2017/8. N2 - This article used probabilistic analysis to evaluate material properties of the in vivo subject-specific tibiofemoral (TF) joint model. Sensitivity analysis, based on a Monte Carlo (MC) method, was performed using a subject-specific finite element (FE) model generated from in vivo computed tomography (CT) and magnetic resonance imaging (MRI) data, subjected to two different loading conditions. Specifically, the effects of inherent uncertainty in ligament stiffness, horn attachment stiffness, and articular surface material properties were assessed using multifactorial global sensitivity analysis. The MRI images were taken before and after ...
When immobile or neuropathic patients are supported by beds or chairs, their soft tissues undergo deformations that can cause pressure ulcers. Current support surfaces that redistribute under-body pressures at vulnerable body sites have not succeeded in reducing pressure ulcer prevalence. Here we show that adding a supporting lateral pressure can counter-act the deformations induced by under-body pressure, and that this pressure equalisation approach is a more effective way to reduce ulcer-inducing deformations than current approaches based on redistributing under-body pressure. A finite element model of the seated pelvis predicts that applying a lateral pressure to the soft tissue reduces peak von Mises stress in the deep tissue by a factor of 2.4 relative to a standard cushion (from 113 kPa to 47 kPa)-a greater effect than that achieved by using a more conformable cushion, which reduced von Mises stress to 75 kPa. Combining both a conformable cushion and lateral pressure reduced peak von Mises
The mechanical effects of varying the depth of cement penetration in the cement-bone interface were investigated using finite element analysis (FEA) and validated using companion experimental data. Two FEA models of the cement-bone interface were created from micro-computed tomography data and the penetration of cement into the bone was varied over six levels each. The FEA models, consisting of the interdigitated cement-bone constructs with friction between cement and bone, were loaded to failure in tension and in shear. The cement and bone elements had provision for crack formation due to excessive stress. The interfacial strength showed a strong relationship with the average interdigitation (r(2)=0.97 and r(2)=0.93 in tension and shear, respectively). Also, the interface strength was strongly related with the contact area (r(2)=0.98 and r(2)=0.95 in tension and shear, respectively). The FEA results compared favorably to the stiffness-strength relationships determined experimentally. Overall, ...
The ideal built-in tip and torque values of the straight wire appliance reduce the need for wire bending and hence reduce chair time. The vertical position of the bracket on the tooth surface can alter the torque exerted on the tooth. This is a result of the altered surface curvature observed at each vertical position. To further clarify the role of vertical bracket positioning on the applied torque and the resultant stresses in the periodontal ligament (PDL), we designed a mandibular first premolar using finite element modeling. Cone beam computed tomography of 52 patients (83 lower first premolars) was selected to be included in the study. Curvature was measured for points along the labial surface with increasing distances (0.5 mm increments) from the cusp tip by calculating the angle between tangents drawn from these points and the axis joining the cusp tip and the root apex. The mean values for each distance were calculated, and a finite element model was designed incorporating these mean values.
Authors: Robau-Porrua, Amanda , Pérez-Rodríguez, Yoan , Soris-Rodríguez, Laura M. , Pérez-Acosta, Osmel , González, Jesús E. Article Type: Research Article Abstract: This study investigated the effect of three different parameters of a dental implant on stress and strain values in the peri-implant bone by finite element analysis. In this work, the effect of diameter, length and elastic modulus on the biomechanical behavior of a new dental implant was simulated using the finite element method. A three-dimensional model of a mandible segment corresponding to the premolar region and twelve dental implant models were obtained. Loads in three directions were distributed on the surface of the coronal area of the dental implants. The dental implant models were obtained in the FreeCAD 0.16 software …and the simulations were made using the Abaqus/CAE software. In all cases, higher stress concentrations were obtained in the peri-implant cortical bone between 40.6 and 62.8 MPa, while the highest ...
Abstract: Being as a functional material, piezoelectric ceramics is applied to drive a micropump when it is composed to be a thin membrane on a brass film to form a diaphragm. According to the properties of the piezoelectric material, the stiffness of the diaphragm influences the vibration displacement and therefore the supply flow rate of the micropump. This paper focuses on the dynamic characteristic study of the micropump and the stiffness influence of the diaphragm on the characteristics. The mathematical model of the valve-less micropump considering the diaphragm stiffness is developed in order to predict the dynamic characteristics of the piezoelectric valve-less micropump. Using the 3-D finite element analysis (FEA) method, the static and vibration mode of the diaphragm are analyzed to obtain the diaphragm stiffness and natural frequency. The method using Matlab is to predict the pressure and flow rate characteristics of the micropump when the diaphragm stiffness is considered or not. ...
TY - JOUR. T1 - Effects of material properties on bacterial adhesion and biofilm formation. AU - Song, F.. AU - Koo, H.. AU - Ren, D.. PY - 2015/8/25. Y1 - 2015/8/25. N2 - Adhesion of microbes, such as bacteria and fungi, to surfaces and the subsequent formation of biofilms cause multidrug-tolerant infections in humans and fouling of medical devices. To address these challenges, it is important to understand how material properties affect microbe-surface interactions and engineer better nonfouling materials. Here we review the recent progresses in this field and discuss the main challenges and opportunities. In particular, we focus on bacterial biofilms and review the effects of surface energy, charge, topography, and stiffness of substratum material on bacterial adhesion. We summarize how these surface properties influence oral biofilm formation, and we discuss the important findings from nondental systems that have potential applications in dental medicine.. AB - Adhesion of microbes, such as ...
Abdominal aortic aneurysm (AAA) is the gradual weakening and dilation of the infrarenal aorta. This disease is progressive, asymptomatic, and can eventually lead to rupture-a catastrophic event leading to massive internal bleeding and possibly death. The mechanical environment present in AAA is currently thought to be important in disease initiation, progression, and diagnosis. In this study, we utilize porohyperelastic (PHE) finite element models (FEMs) to investigate how such modeling can be used to better understand the local biomechanical environment in AAA. A 3D hypothetical AAA was constructed with a preferential anterior bulge assuming both the intraluminal thrombus (ILT) and the AAA wall act as porous materials. A parametric study was performed to investigate how physiologically meaningful variations in AAA wall and ILT hydraulic permeabilities affect luminal interstitial fluid velocities and wall stresses within an AAA. A corresponding hyperelastic (HE) simulation was also run in order ...
A multiscale design and multiobjective optimization procedure is developed to design a new type of graded cellular hip implant. We assume that the prosthesis design domain is occupied by a unit cell representing the building block of the implant. An optimization strategy seeks the best geometric parameters of the unit cell to minimize bone resorption and interface failure, two conflicting objective functions. Using the asymptotic homogenization method, the microstructure of the implant is replaced by a homogeneous medium with an effective constitutive tensor. This tensor is used to construct the stiffness matrix for the finite element modeling (FEM) solver that calculates the value of each objective function at each iteration. As an example, a 2D finite element model of a left implanted femur is developed. The relative density of the lattice material is the variable of the multiobjective optimization, which is solved through the non-dominated sorting genetic algorithm II (NSGA-II). The set of ...
Cam femoroacetabular impingement (FAI) can impose elevated mechanical loading in the hip, potentially leading to an eventual mechanical failure of the joint. Since in vivo data on the pathomechanisms
In the study of mechanical properties of materials, isotropic means having identical values of a property in all directions. This definition is also used in geology and mineralogy. Glass and metals are examples of isotropic materials.[3] Common anisotropic materials include wood, because its material properties are different parallel and perpendicular to the grain, and layered rocks such as slate. Isotropic materials are useful since they are easier to shape, and their behavior is easier to predict. Anisotropic materials can be tailored to the forces an object is expected to experience. For example, the fibers in carbon fiber materials and rebars in reinforced concrete are oriented to withstand tension. ...
TY - GEN. T1 - Study of ultrasonic upsetting under radial and longitudinal die vibration. AU - Huang, Zhi Hong. AU - Lucas, M.. AU - Adams, M.J.. N1 - Copyright 2010 Elsevier B.V., All rights reserved.. PY - 2003. Y1 - 2003. N2 - A finite element analysis was described for the upsetting of a cylindrical specimen between two parallel rigid dies. The benefits of radial and longitudinal ultrasonic oscillation of the die in compressive deformation of a model soft solid were studied. The influence of oscillation direction on the interfacial friction boundary condition and thermal effects during the process was investigated. It was observed that oscillation in the radial direction results in greater reductions in forming force and friction.. AB - A finite element analysis was described for the upsetting of a cylindrical specimen between two parallel rigid dies. The benefits of radial and longitudinal ultrasonic oscillation of the die in compressive deformation of a model soft solid were studied. The ...
Structured grids with regular shaped uniform elements are easy to generate automatically and have been used in extended finite element approaches to avoid mesh generation difficulties. But the grid or mesh should ideally have higher resolution in areas where the solution has large gradients. In this paper a technique for refinement of structured grids is presented that allows refinement of the grid without violating compatibility requirements by using solution structures constructed using approximate step functions. Essential boundary conditions are applied using implicit boundary method, which allows boundary conditions to be imposed even when there are no nodes on the boundary. This grid refinement technique is evaluated using two dimensional elasticity problems that involve stress concentration.. Copyright © 2009 by ASME ...
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As in all tissues, mechanical forces in the aortic valve (AV) modulate the constituent cell populations physiology and biosynthetic activity. While advances have been made toward the understanding of this complex multi-scale relationship, the specific role that and extracellular matrix (ECM) coupling plays on the mechanical response of the AV interstitial cell (AVIC) is poorly understood. The current work, building on our previous preliminary work [1], explores the impact of cellular contractile behavior on effective tissue level stiffness in an effort to gain insight into the complex mechanisms involved. By developing a computational tool to separate intrinsic cell mechanics from the ECM in-situ, we can obtain an accurate representation of AVIC behavior within the native valve connective tissue matrix microenvironment. Two computational finite element (FE) models were developed using COMSOL Multiphysics 4.3 that represent the tissue-level (macro-scale) and the cell level (micro-scale) of the ...
This paper deals with the study of the nonlinear dynamics of a rotating flexible link modeled as a one dimensional beam, undergoing large deformation and with geometric nonlinearities. The partial differential equation of motion is discretized using a finite element approach to yield four nonlinear, nonautonomous and coupled ordinary differential equations (ODEs). The equations are nondimensionalized using two characteristic velocities-the speed of sound in the material and a velocity associated with the transverse bending vibration of the beam. The method of multiple scales is used to perform a detailed study of the system. A set of four autonomous equations of the first-order are derived considering primary resonances of the external excitation and one-to-one internal resonances between the natural frequencies of the equations. Numerical simulations show that for certain ranges of values of these characteristic velocities, the slow flow equations can exhibit chaotic motions. The numerical ...
Mathematical Problems in Engineering is a peer-reviewed, Open Access journal that publishes results of rigorous engineering research carried out using mathematical tools. Contributions containing formulations or results related to applications are also encouraged. The primary aim of Mathematical Problems in Engineering is rapid publication and dissemination of important mathematical work which has relevance to engineering. All areas of engineering are within the scope of the journal. In particular, aerospace engineering, bioengineering, chemical engineering, computer engineering, electrical engineering, industrial engineering and manufacturing systems, and mechanical engineering are of interest. Mathematical work of interest includes, but is not limited to, ordinary and partial differential equations, stochastic processes, calculus of variations, and nonlinear analysis.
Naramar Hardness indentation technique and stress-strain characteristics in compression. Water from to generate carbon dioxide gas reacts with the polyisocyanate component, which acts as a blowing agent.. For wood adhesives in wood composites, the internal bond strength test can be done with a or testing machine to determine the tensile strength. This is succeeding model of AF Series which had many delivery result to car industries, seat kis, raw materials manufacturers and public enterprises etc.. Chiao Fu Enterprise Co. AF Series is Automatic Hardness Tester for flexible urethane foams to be used for cushion materials in such products as car seat, furniture, and bedding, and for other kind of plastic foam. JIS-S This tester is for evaluating the strength and durability of furniture such as chairs or stools. A finite element approach with simplified room descriptionActa Acustica united with Acustica, , - Flexible polyurethane foam, process for its production, and seat for ...
In this study, the effects of these parameters on the fatigue life of spot-weld joints have been investigated. For this purpose, one of the most reliable fatigue assessment models, Coffin-Manson approach, was used. In order to accurately determine the stress and strain states, a nonlinear finite element analysis was carried out taking into account plastic deformations, residual stresses developed after unloading and contacting surfaces. The results provide designers with some guidelines to foresee the impact of design changes on fatigue strength of spot-weld joints ...
The characterization of the mechanical properties of soft materials has been traditionally performed through uniaxial tensile tests. Nevertheless, this method cannot be applied to certain extremely soft materials, such as biological tissues or cells that cannot be properly subjected to these tests. Alternative non-destructive tests have been designed in recent years to determine the mechanical properties of soft biological tissues. One of these techniques is based on the use of atomic force microscopy (AFM) to perform nanoindentation tests. In this work, we investigated the mechanical response of soft biological materials to nanoindentation with spherical indenters using finite element simulations. We studied the responses of three different material constitutive laws (elastic, isotropic hyperelastic and anisotropic hyperelastic) under the same process and analyzed the differences thereof. Whereas linear elastic and isotropic hyperelastic materials can be studied using an axisymmetric ...
An effective method has been developed for analysis of the multiharmonic forced response of large-scale finite element models of bladed discs with contact interfaces at blade roots. Area contact elements are developed to model nonlinear forces acting at the contact surfaces. The elements allow for unilateral normal and tangential friction contact forces. The friction model includes effects of the variable normal load and variation of the contact area. Numerical investigations of the forced response for realistic finite element models of bladed discs with root damping are performed for the first time. ...
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The rupture of atherosclerotic plaques is known to be associated with the stresses that act on or within the arterial wall. The extreme wall tensile stress is usually recognized as a primary trigger for the rupture of the plaque. The present study used one-way fluid-structure interaction simulation to investigate the impacts of fibrous cap thickness and lipid core volume to the wall tensile stress value and distributions on the fibrous cap. Von Mises stress was employed to represent the wall tensile stress (VWTS). A total of 13 carotid bifurcation cases were manipulated based on a base geometry in the study with varied combinations of fibrous cap thickness and lipid core volume in the plaque. Values of maximum VWTS and a stress value of VWTS_90, which represents the cut-off VWTS value of 90% in cumulative histogram of VWTS possessed at the computational nodes on the luminal surface of fibrous cap, were used to assess the risk of plaque rupture for each case. Both parameters are capable of ...
Finite element models of human body segments have been developed in recent years. Numerical simulation could be helpful when understanding injury mechanisms and to make injury assessments. In the lower leg injury research in NISSAN, a finite element model of the human ankle/foot is under development. The mesh for the bony part was taken from the original model developed by Beaugonin et al., but was revised by adding soft tissue to reproduce realistic responses. Damping effect in a high speed contact was taken into account by modeling skin and fat in the sole of the foot. The plantar aponeurosis tendon was modeled by nonlinear bar elements connecting the phalanges to the calcaneus. The rigid body connection, which was defined at the toe in the original model for simplicity, was removed and the transverse ligaments were added instead in order to bind the metatarsals and the phalanges. These tendons and ligaments were expected to reproduce a realistic response in compression ...
Hot compression molding is a promising method to fabricate polymer stand-alone microlenses. A reliable theoretical as well as statistical analysis is required for the optimization of the process to minimize the residual stresses and to predict the amount of springback to achieve a better replication of the mold profile. This article in this context focuses on the finite element simulation (FES), optimization as well as experimental validation of hot compression molding of polymer stand-alone microlenses. Three steps such as molding, cooling, and demolding, under different molding parameters, were analyzed using ABAQUS/standard solver and the results were compared with experimental results. Compression test and compression relaxation test have been conducted at different temperatures and strain rates to characterize the rheological behavior of material. Two material models, linear viscoelastic and hyperelastic-viscoelastic models, were developed and used for compression test simulations. ...
Insulated Gate Bipolar Transistors (IGBTs) are widely used in the automotive industry as high power current switches. They are currently being introduced into traction applications (locomotives, trams, metros, etc.) where high reliability is extremely important. Modern locomotives have a lifetime of about 30 years during which they should not fail. Due to the complexity of the modules as mechanical systems and as electric circuits, it is of prime importance to select and set up the most suitable models which allow to extract valuable data. Accordingly, this work describes the models and associated equations which appear to be necessary to carry out failure analysis. It includes a general stationary fully coupled electro-thermomechanical analysis which is actually part of the commercial release of the software SOLIDIS-ISE. More specific features tailored to IGBTs failure analysis are currently implemented. It comprises thermal transient effects and plasticity/damage based models for the stress analysis.
Copyright in the material you requested is held by the American Society of Mechanical Engineers (unless otherwise noted). This email ability is provided as a courtesy, and by using it you agree that you are requesting the material solely for personal, non-commercial use, and that it is subject to the American Society of Mechanical Engineers Terms of Use. The information provided in order to email this topic will not be used to send unsolicited email, nor will it be furnished to third parties. Please refer to the American Society of Mechanical Engineers Privacy Policy for further information ...
Little guidance is available in the public domain for the design of the profiled blastwalls commonly used in offshore structures to resist accidental explosions. The provision of the Technical Note 5 (TN5) has helped to bridge some of the gaps and it deals mainly with the Single Degree of Freedom method (SDOF) to obtain the dynamic response of the blastwalls. The adequacy of the design guide is assessed by comparison with numerical nonlinear finite element models for three profiled sections with different degree of compactness. The static capacity and the dynamic response of the blast walls are established up to their maximum capacity level and into the post peak or buckling response regime. Effects of cross section flattening, local transverse effects, support rotation and the effects of cross section compactness on the overall behaviour of the blast barriers are discussed. Copyright © 2004 by The International Society of Offshore and Polar Engineers ...