Mechanics of Angioplasty: Wall, Balloon and Stent

2000 ◽  
Author(s):  
Gerhard A. Holzapfel ◽  
Christian A. J. Schulze-Bauer ◽  
Michael Stadler
Keyword(s):  
Solid Mechanics ◽  
Three Dimensional ◽  
Element Model ◽  
Biological Tissues ◽  
Interventional Treatment ◽  
Strong Nonlinearity ◽  
Three Dimensional Model ◽  
Plaque Disruption ◽  
Geometrical Data ◽  
Elastoplastic Constitutive Model

Abstract Studying the solid mechanics of angioplasty provides essential insight in the mechanisms of angioplasty such as overstretching the disease-free tissue, plaque disruption or dissection, redistribution inside the wall and lipid extrusion etc. We desribe our current understanding of the mechanics of angioplasty based on the example of a human iliac artery with an eccentric stenosis. We outline a new approach which has the potential to improve interventional treatment planning, to predict the balloon and stent-induced wall stresses as well as the dilation success. In particular, we use MRI to obtain accurate geometrical data for the vessel wall and plaque architecture and to identify their different types of soft (biological) tissues and calcifications. One issue is to characterize the quasistatic stress-strain response of these components in both axial and circumferential directions. We present new experimental results showing strong nonlinearity and anisotropy. Another issue is to identify predominant directions of each component by analyzing orientations of cellular nuclei. The morphological and mechanical information is used for the elastoplastic constitutive model designed to capture the finite strains of the stenotic artery during angioplasty. The three-dimensional model is fitted to the experimental data. Associated material parameters, corresponding to the different tissues of the stenosis, are presented. The numerical part outlines briefly the concept of the finite element model and, based on a computational structural analysis, discusses the mechanism of angioplasty for the considered type of stenosis.

The Application of Moldflow in Injection Mold Design of Mobile Phone Cover

2011 ◽  
Vol 228-229 ◽  
pp. 542-547
Author(s):  
Wen Jian Zhang ◽  
Qi Zhang
Keyword(s):  
Mobile Phone ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Mold Design ◽  
Injection Mold ◽  
Three Dimensional Model ◽  
Molding Process ◽  
Injection Mold Design ◽  
Cae Technology

Based the CAE technology, the paper introduced the application of Moldflow Insight in injection mold design of mobile phone cover. First, we must preprocess the finite element model, including importing three-dimensional model, meshing, and process setting. And then, we can use preliminary simulation analysis to determine the number and location of the gate. Finally to filling, cooling, packing and warpage analysis for part which can help us to find the causes from warpage generated. By optimizing the molding process parameters, adjusting the dwell pressure and the dwell time we can get less warpage, which can meet the precision demand of parts, consequently, the result can provide gist for the mold designers to design and for the injection molding technologist to process parameter adjustment.

scholarly journals Stress analysis of a second stage gas turbine blade under asymmetric thermal gradient

2019 ◽  
Vol 20 (6) ◽  
pp. 607
Author(s):  
Javad Rahimi ◽  
Esmaeil Poursaeidi ◽  
Ehsan Khavasi
Keyword(s):  
Stress Distribution ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Element Model ◽  
The State ◽  
Three Dimensional Model ◽  
Cooling Mode ◽  
Cooling Channels ◽  
Second Stage ◽  
Main Factor

In this study the main causes of the failure of a GE-F9 second stage turbine blade were investigated. The stress distribution of the blade which has 6 cooling vents in three modes (with full cooling, closure of half of the cooling channels, and without cooling) was studied. A three dimensional model of the blade was built and the fluid flow on the blade was studied using the FVM method. The stress distribution due to centrifugal forces applied to the blade, temperature gradients and aerodynamic forces on the blade surface was calculated by the finite element model. The results show that the highest temperature gradient and as a result the highest stress value occurs for the semi-cooling state at the areas near the blade root and this status is true for the full cooling mode for the regions far from the root. However, the field observations showed that the failure occurred for the blade with the semi-cooling state (due to closure of some of the channels) at areas far from the root. It is discussed that the main factor of the failure is not the stress values being maximum because in the state of full cooling mode (the state with the maximum stress values) the temperature of the blade is the lowest state and as a result the material properties of the blade show a better resistance to phenomena like hot corrosion and creep.

The Radial Fretting Character Research of the Shaft-Hub of Compress Impeller Based on Virtual Orthogonal Experiment

2014 ◽  
Vol 668-669 ◽  
pp. 289-293
Author(s):  
Xue Long Lu ◽  
Jun Sheng Zhao ◽  
Xin Zhong Huang ◽  
Shuang Yong Wang
Keyword(s):  
Orthogonal Experiment ◽  
Orthogonal Design ◽  
Three Dimensional ◽  
Element Model ◽  
Optimization Method ◽  
Three Dimensional Model ◽  
Interference Fit ◽  
Rotating Speed ◽  
Compressor Impeller ◽  
Set Up

A three-dimensional model of as haft-hub of compressor impeller was set up by Pro/E. Based on the ANSYS; the finite element model was established, using the analysis method of combining submodle and paramesh. The shaft-hub of compressor impeller was simulated by virtual orthogonal design optimization method. Based on the fact that there existed radial fretting in the shaft-hub interference fit joint, researching the influence significance order and law of interference, friction coefficient and rotating speed to the maximum unit frictional work , the average friction work and the optimized parameter were obtained. It turned out that the results of the numerical simulation and orthogonal experiment were accurate and reliable, with the friction and wear effectively reduced, certain guiding references to actual assembly process were got.

Modal Analysis of Two Wheels Scooter Based on Solidworks

2014 ◽  
Vol 960-961 ◽  
pp. 1420-1423
Author(s):  
Zhi Dong Huang ◽  
Guo Fei Li ◽  
Juan Cong ◽  
Yun Wang ◽  
Wei Na Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Dynamic Design ◽  
Driving System ◽  
Set Up ◽  
The Finite Element Model

Based on Solidworks software, the three-dimensional model of two wheels scooter is set up. The finite element model of two wheels scooter is generated. Modal analysis of driving system and telescopic mechanism of bar on two wheels scooter is investigated. The first five orders natural frequency and major modes of driving system and telescopic mechanism of bar are clarified. The method and the result can be used as a reference of dynamic design and lay foundation for calculation and analysis of dynamic response for the two wheels scooter.

scholarly journals Analysis of historical structures by using finite element method in Iznik Yeşil Mosque

2019 ◽  
Vol 5 (4) ◽  
pp. 121
Author(s):  
Aykut Uray ◽  
Hasan Selim Şengel ◽  
Serdar Çarbaş
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Soil Survey ◽  
Three Dimensional Model ◽  
Historical Structures ◽  
Model Study ◽  
Non Destructive ◽  
The Finite Element Model

In this study, non-destructive tests and laboratory tests were carried out in order to determine the material properties in Iznik Yeşil Mosque, Iznik District, Bursa Province. For the purpose of determining the soil characteristics of the building, the soil survey studies conducted in the Iznik Yeşil Mosque area were investigated. The finite element model was formed by making a three dimensional model study of the structure. With the finite element model, static analysis, modal analysis and behavioral spectrum analysis were performed under vertical loads in order to collect data for the damaged areas of the structure.

FEM Simulation and Analysis of Variable Parameters for the Three-Roll Cylindrical Bending of Plate Process

2010 ◽  
Vol 160-162 ◽  
pp. 809-814 ◽  
Author(s):  
Jian Hao ◽  
Zhen Luo ◽  
Jian Tao Dong ◽  
J.W. Zhang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Element Model ◽  
Cylindrical Shape ◽  
Three Dimensional Model ◽  
Variable Parameters ◽  
Roll Bending ◽  
Roll Plate ◽  
Explicit Dynamic

A three-dimensional model is developed to study the dynamic process of three-roll plate bending using finite element method (FEM). In this work, the continuous three-roll bending configuration with cylindrical rolls is used to bend a thick plate into a cylindrical shape. It presents the geometrical setup and the finite element model. This 3D simulation is based on the elastic plastic explicit dynamic FEM under the ANSYS/LS-DYNA environment. Effect of initial strain and change of material properties during deformation is neglected. In order to investigate the influence of parameters on the process, top roller position, friction between rolls and plate, and temperature are also discussed. It is found that the simulation program is a feasible and economical method to study the influence of these parameters, and the FEM simulation can also provide engineers with a convenient analytical tool for optimizing process parameters.

The Parametric Analysis of the Threshold Value Judging Mechanism in MEMS Safety and Arming Device

2015 ◽  
Vol 645-646 ◽  
pp. 968-971
Author(s):  
Fu Fu Wang ◽  
Wen Zhong Lou ◽  
Fang Yi Liu ◽  
Da Kui Wang ◽  
Ming Rong Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Threshold Value ◽  
Element Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Long Distance ◽  
And Control ◽  
The Mathematical Model ◽  
The Finite Element Model

In this paper, a mechanical MEMS S&A device has been proposed. The size of the device is 10mm×13mm×0.5mm. The role of the threshold value judging mechanism is to determine the environment suffered by centrifugal force and control the sub-centrifugal slider not movement under the threshold, so as to effectively guarantee the time of long-distance arming. Through establishing the three-dimensional model of threshold value judging mechanism, establishing the force and the parameters of locking-releasing mechanism, deriving the mathematical model according to the rigid dynamic mechanics theory and establishing the finite element model by using ANSYS/LS-DYNA, appropriate threshold value judging mechanism is designed to meet two items, one item is the deformation of threshold value rod is not enough to release sub-centrifugal slider when the speed is less than 60000r/min; the other item is deformation of threshold value rod can release sub-centrifugal slider when the speed is more than 60000r/min.

Three-Dimensional Analysis of Continuously Reinforced Concrete Pavements

2000 ◽  
Vol 1730 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Seong-Min Kim ◽  
Moon C. Won ◽  
B. Frank McCullough
Keyword(s):  
Reinforced Concrete ◽  
Three Dimensional ◽  
Drying Shrinkage ◽  
Nonlinear Effects ◽  
Element Model ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Transverse Steel ◽  
Three Dimensional Finite Element

Continuously reinforced concrete pavement (CRCP) performance depends primarily on early-age cracks that result from changes in temperature and drying shrinkage. Presented is the behavior of the CRCP due to the temperature change obtained by using a three-dimensional finite element model. The nonlinear effects of the bond-slip between concrete and steel and between concrete and base have been studied. Modeling for the curling effect and for the viscoelastic material characteristics also has been considered. The results from the two-dimensional and three-dimensional models have been compared to verify the possibility of using a two-dimensional model. From this study, it was found that crack width and concrete stress are dependent on the transverse steel arrangement near the edge (longitudinal joint), but they are almost independent in the interior of the slab. The tensile stress occurring at the top of the edge on the transverse steel location can be higher than that occurring at the top of the slab center. This represents the possibility of forming a transverse crack from the edge on the transverse steel location. The twodimensional model with the plane stress element gives results very close to those of the three-dimensional model, except near the edge.

Impact of Welding Sequence on the CRDM Nozzle-to-Vessel Weld Stress Analysis

2004 ◽  
Author(s):  
Yaoshan Chen ◽  
David Rudland ◽  
Gery Wilkowski
Keyword(s):  
Computing Time ◽  
Three Dimensional ◽  
Welding Process ◽  
Element Model ◽  
Three Dimensional Model ◽  
Control Rod ◽  
Moving Source ◽  
Welding Sequence ◽  
Significant Difference ◽  
Three Dimensional Finite Element

A three-dimensional finite element model is presented to simulate the welding process of the side-hill control-rod-drive-mechanism (CRDM) nozzle to the vessel head. Emphasis is given to how the weld is laid out in the analysis so that accurate residual stress results can be obtained while the required computing time is viable. In the order of complexity, three approaches are examined in this study: a) the simultaneous approach, i.e., the weld bead (therefore the heat associated with it) is put in the model in a uniform fashion; b) the piece-by-piece approach, i.e., the weld is laid out segment by segment; c) the moving-source approach where the analysis is done by simulating the moving heat source. It is found that there is a significant difference between the stress results by the uniform approach and the piece-by-piece approach. While the moving source method gives the closet representation of the welding process, the computing time for such a multi-pass, three-dimensional model is still prohibitive. The natural choice is therefore the piece-by-piece approach, with the number of segments for the weld dependent on the weld parameters and the geometries of the nozzle and vessel head.

Finite Element Analysis of Key Component on Two Wheels Scooter

2014 ◽  
Vol 597 ◽  
pp. 531-534
Author(s):  
Zhi Dong Huang ◽  
Yun Pu Du ◽  
Bao Quan Liu ◽  
Guang Yang ◽  
Yu Feng Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Strain Diagram ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Innovative Design ◽  
Driving System ◽  
Set Up

Based on Solidworks software, the three-dimensional model of two wheels scooter is set up. The finite element model of two wheels scooter is generated. Finite element analysis of driving system on two wheels scooter is investigated. The stress and strain of driving system is investigated. The stress diagram and the strain diagram are obtained. The method and the result can be used as a reference of innovative design of two wheels scooter.

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