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 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.

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.

Influence of the TMJ Implant Geometry on Stress Distribution

2012 ◽  
Vol 488-489 ◽  
pp. 991-995 ◽  
Author(s):  
Zohreh Arabshahi ◽  
Jamal Kashani ◽  
Mohammed Rafiq Abdul Kadir ◽  
Abbas Azari
Keyword(s):  
Stress Distribution ◽  
Temporomandibular Joint ◽  
Contact Surface ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Surface Region ◽  
Implant Design ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Applied Loading

The purpose of this study was to investigate the influence of Temporomandibular Joint implant geometry on stress distribution in total reconstruction of temporomandibular joint. A three dimensional model of a lower jaw of a patient was developed from a Computed Tomography scan images. Anatomical curvature and flat contact surface of implant design and fixation screws were modeled. Two implanted mandibles were then compared by means of finite element analysis. The muscle forces for incisal clenching were applied. The equivalent stress resulted in contact surface region of the bone and implant and in fixation screw holes were investigated to evaluate the designs. In applied loading condition, The results showed that anatomical design of implant was more preferred and it will lead to long-term success of implant.

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.

A Three Dimensional Finite Element of Anterior Cruciate Ligament Model

2012 ◽  
Vol 626 ◽  
pp. 896-901
Author(s):  
A.H. Alafiah ◽  
M. Normahira ◽  
M.N. Anas
Keyword(s):  
Finite Element ◽  
Anterior Cruciate Ligament ◽  
Stress Distribution ◽  
Contact Pressure ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Knee Ligament ◽  
Suitable Material ◽  
Anterior Cruciate

Anterior Cruciate Ligament (ACL) is of the major knee ligament. A three dimensional model that reflects the geometric characteristics of the human ACL developed to explore and analyze finite element parameters such as contact pressure and stress distribution on ACL in response to complex loading conditions. Moreover, various cases studied such as cases involving and uninvolving ligament in order to obtain and analyze the stress and contact pressure relationship between ACL, meniscus and cartilage. It is known that the contact and friction caused by the ACL wrapping around the bone during knee motion played the role of transferring the force from the ACL to the bone, and had a direct effect on the stress distribution of the ACL. Thus, the project lead to better understand the mechanism of injury, to improve the design of ACL reconstruction using suitable material and optimizing rehabilitation protocols by investigation of contact pressure with and without ACL.

scholarly journals Comparative analysis of stress distribution in one-piece and two-piece implants with narrow and extra-narrow diameters: A finite element study

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245800
Author(s):  
Fabricia Teixeira Barbosa ◽  
Luiz Carlos Silveira Zanatta ◽  
Edélcio de Souza Rendohl ◽  
Sergio Alexandre Gehrke
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Von Mises Stress ◽  
Axial Loads ◽  
Three Dimensional Model ◽  
The One ◽  
Von Mises

Objectives The aim of this in vitro study was to evaluate the stress distribution on three implant models with narrow and extra-narrow diameters using the finite element method (FEA). Materials and methods Dental implants of extra-narrow diameter of 2.5 mm for a one-piece implant (group G1), a narrow diameter of 3.0 mm for a one-piece implant (group G2) and a narrow diameter of 3.5 mm for a two-piece implant with a Morse taper connection (group G3). A three-dimensional model was designed with cortical and cancellous bone, a crown and an implant/abutment set of each group. Axial and angled (30°) loads of 150 N was applied. The equivalent von Mises stress was used for the implants and peri-implant bone plus the Mohr-Coulomb analysis to confirm the data of the peri-implant bone. Results In the axial load, the maximum stress value of the cortical bone for the group G1 was 22.35% higher than that the group G2 and 321.23% than the group G3. Whereas in angled load, the groups G1 and G2 showing a similar value (# 3.5%) and a highest difference for the group G3 (391.8%). In the implant structure, the group G1 showed a value of 2188MPa, 93.6% higher than the limit. Conclusions The results of this study show that the extra-narrow one-piece implant should be used with great caution, especially in areas of non-axial loads, whereas the one- and two-piece narrow-diameter implants show adequate behavior in both directions of the applied load.

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.

scholarly journals A Finite Element Analysis to Compare Stress Distribution on Extra-Short Implants with Two Different Internal Connections

2019 ◽  
Vol 8 (8) ◽  
pp. 1103 ◽  
Author(s):  
García-Braz ◽  
Prados-Privado ◽  
Zanatta ◽  
Calvo-Guirado ◽  
Prados-Frutos ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Axial Load ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Stress Concentrations ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Short Implants

Background: The goal of this study was to analyze the stress distribution on two types of extra-short dental implants with 5 mm of length: An internal hexagon (IH) and morse taper connection (MT). Methods: The three-dimensional model was composed of trabecular and cortical bone, a crown, an extra-short dental implant and their components. An axial load of 150 N was applied and another inclined 30° with the same magnitude. Results: Stress concentrations on the IH implant are observed in the region of the first threads for the screw. However, in the MT implant the highest stress occurs at the edges of the upper implant platform. Conclusions: In view of the results obtained in this study the two types of prosthetic fittings present a good stress distribution. The Morse taper connections presented better behavior than the internal in both loading configurations.

Effect of Friction on Residual Stress Distribution Induced by Split Sleeve Cold Expansion Process

2020 ◽  
Author(s):  
Mithun K. Dey ◽  
Dave Kim ◽  
Hua Tan
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Compressive Residual Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Distribution ◽  
Expansion Process ◽  
Cold Expansion ◽  
Three Dimensional Finite Element

Abstract Residual Stress distribution and parametric influence of friction are studied for the split sleeve cold expanded holes in Al 2024 T351 alloy, by developing a three-dimensional finite element model of the process. Fastener holes in the alloy are necessary for the manufacturing process, but they create a potential area for stress concentration, which eventually leads to fatigue under cyclic loading. Beneficial compressive residual stress distribution as a result of the split sleeve cold expansion process provides retardation against crack initiation and propagation at the critical zones near hole edges. In this parametric study, the influence of friction between contact surfaces of the split sleeve and mandrel is numerically investigated. Hole reaming process after split sleeve cold expansion is often not discussed. Without this post-processing procedure, split sleeve cold expansion is incomplete in practice, and its purpose of providing better fatigue performance is invalidated. This study presents results and an overview of the significance of friction with the consideration of the postprocessing of split sleeve cold expansion. The numerical results show that with increasing friction coefficient, compressive residual stress reduces significantly at the mandrel entry side, which makes the hole edge more vulnerable to fatigue. The different aspects of finite element modeling approaches are also discussed to present the accuracy of the prediction. Experimental residual stress observation or visual validation is expensive and time-consuming. So better numerical prediction with the transparency of the analysis design can provide critical information on the process.

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.

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