scholarly journals Numerical Simulation and Mechanism Analysis on the Concave Deformation of Automotive Dry Clutch Pressure Plate

2019 ◽  
Vol 9 (23) ◽  
pp. 5017
Author(s):  
Yubing Gong ◽  
Penghui Wang ◽  
Wencheng Ge ◽  
Yun-Bo Yi
Keyword(s):  
Room Temperature ◽  
Von Mises Stress ◽  
Mechanism Analysis ◽  
Cooling Process ◽  
Pressure Plate ◽  
Thermal Stress Distribution ◽  
Dry Clutch ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Plate Assembly

It is well known that slipping in automotive clutches is closely related to the concave deformation of the pressure plate, but the mechanism of this deformation is not clear. A simplified model of a pressure plate assembly is developed by simulating the deformation field of the plate under the condition of continuous sliding, followed by natural cooling to room temperature. The distribution of displacement is obtained from numerical simulations. The equivalent von Mises stresses of the pressure plate with or without concave deformation are analyzed and compared. The mechanism leading to the concave deformation of the pressure plate is put forward in terms of equivalent von Mises stress. The results show that (1) the concave deformation of the pressure plate is produced during the cooling process and (2) the profile of the concave deformation is determined by its thermal stress distribution. The deformation is mainly caused by the overstressed upper part of the inner rim of the pressure plate during clutch operations.

A fretting finite element investigation of a plane-strain cylindrical contact of Inconel 617/Incoloy 800H at room and high temperatures

2018 ◽  
Vol 233 (4) ◽  
pp. 553-569 ◽  
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Room Temperature ◽  
Tangential Force ◽  
Alloy 800H ◽  
Incoloy 800H ◽  
Inconel 617 ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Two Bodies

This work presents a finite element study of a 2D plane strain fretting model of a half-cylinder in contact with a flat block under oscillatory tangential loading. The two bodies are deformable and are set to Inconel 617 and Incoloy 800H at room temperature (20 ℃) and 800 ℃. However, because the results are normalized, they can characterize a range of contact scales (micro to macro). Different coefficients of friction are used at the interface. This work finds that the edges of the contacting areas experience large von Mises stresses along with significant residual plastic strains, while pileup could also appear when the coefficients of friction are sufficiently large. In addition, junction growth is investigated, showing that the direction of the growth is in the same direction of the tangential force that the weaker material (Incoloy alloy 800H) experiences. The fretting loop (caused by the tangential force during the fretting motion) for the initial few cycles of loading is generated, and it compares well with the reported experimental results. The different extents of damage at room temperature and 800 ℃ are also compared.

Analysis of Loads and Stresses for a Sewing Needle

2002 ◽  
Author(s):  
Yuan Mao Huang
Keyword(s):  
Shear Stress ◽  
Personal Computer ◽  
Failure Modes ◽  
Von Mises Stress ◽  
Bending Stress ◽  
Principal Stresses ◽  
Acceptable Accuracy ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Cost

This study analyzes the loads of a needle by using singularity functions and determines the Von-Mises stresses to predict the failure modes of needles by using a personal computer. After principal stresses are calculated from the bending stress, compressive stress and shear stress, predicted failure modes of needles based on the Von-Mises stress coincide with practical existing failure modes reported by a manufacturer. These calculated stresses are also compared with the results obtained by using the software ABAQUS in the mainframe, and the deviation between the results calculated by these two methods is also investigated. Using this methodology can obtain loads, stresses and failure modes of a needle with acceptable accuracy while reducing the cost of using the commercial software in the mainframe.

scholarly journals Aerodynamic and Structural Characteristics of a Centrifugal Compressor Impeller

2019 ◽  
Vol 9 (16) ◽  
pp. 3416 ◽  
Author(s):  
T R Jebieshia ◽  
Senthil Kumar Raman ◽  
Heuy Dong Kim
Keyword(s):  
Centrifugal Compressor ◽  
Structural Characteristics ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Von Mises Stress ◽  
Impeller Blade ◽  
Compressor Impeller ◽  
The One ◽  
Von Mises ◽  
Von Mises Stresses

The present study focuses on the aerodynamic performance and structural analysis of the centrifugal compressor impeller. The performance characteristics of the impeller are analyzed with and without splitter blades by varying the total number of main and splitter blades. The operating conditions of the compressor under centrifugal force and pressure load from the aerodynamic analysis are applied to the impeller blade and hub to perform the one-way Fluid–Structure Interaction (FSI). For the stress assessment, maximum equivalent von Mises stresses in the impeller blades are compared with the maximum allowable stress of the impeller material. The effects of varying the pressure field on the deformation and stress of the impeller are also calculated. The aerodynamic and structural performance of the centrifugal compressor at 73,000 rpm are investigated in terms of the efficiency, pressure ratio, equivalent von Mises stress, and total deformation of the impeller.

THE BIOMECHANICAL EFFECTS OF CEMENT AUGMENTATION AND PARTIAL VERTEBRAL HEIGHT RESTORATION ON THE LOAD TRANSFER CHANGE OF ADJACENT VERTEBRAE IN VERTEBROPLASTY

2015 ◽  
Vol 15 (03) ◽  
pp. 1550025 ◽  
Author(s):  
CHIEN-YU LIN ◽  
WENG-PIN CHEN ◽  
PO-LIANG LAI ◽  
SHIH-YOUENG CHUANG ◽  
DA-TONG JU ◽  
...  
Keyword(s):  
Load Transfer ◽  
Cement Augmentation ◽  
Erector Spinae ◽  
Von Mises Stress ◽  
Fe Model ◽  
Vertebral Height ◽  
Adjacent Disc ◽  
Before And After ◽  
Von Mises ◽  
Von Mises Stresses

Vertebroplasty is commonly used to treat vertebral wedge fractures (VWFs). However, differing degrees of vertebral height restoration (VHR) have been reported after vertebroplasty, and little is known about how grades (steepness) of VWF deformities affect loadings on the fractured and adjacent unfractured vertebrae. Therefore, the goal of this study was to create a non-linear finite element (FE) model of the T10–L2 thoracolumbar segments. With this model, we aimed to evaluate the biomechanical outcomes of three different collapse models (25%, 50%, and 75%) at the T12 vertebra before and after cement augmentation (CA) and with and without VHR. In these VWF simulations, the forces of the erector spinae, the intradiscal pressure, and the maximum von Mises stresses in the endplates and vertebral bodies increased as vertebral deformation increased. Performing CA alone, without restoring vertebral height for the fractured vertebra, did not change the stiffness of multiple spinal segments or the pressures on the adjacent disc, but it did decrease stresses on the endplates and the vertebral bone. A 10% restoration of vertebral height after CA reduced the maximum von Mises stress in the endplates and bone structures more than when CA did not restore vertebral height (no VHR). These results suggest that achieving partial VHR during vertebroplasty may help prevent postvertebroplasty fractures in the fractured and adjacent vertebrae.

Gun Barrel Refurbishing Using a Shrink-Fitted Autofrettaged Liner

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
J. Perry ◽  
M. Perl
Keyword(s):  
Cross Sections ◽  
Cost Effective ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Internal Diameter ◽  
Original Performance ◽  
Gun Barrel ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Cost

During the firing of guns, the barrel undergoes two major damaging processes: wear of its inner surface and internal cracking. Barrel's are condemned based on either the increase of their internal diameter due to wear or the severity of their internal cracking. The cost of replacing such a damaged gun barrel runs in the tenth of thousands of U.S.$. Therefore, cost effective methods are sought for restoring such gun barrels. In the present analysis, a new method is proposed for refurbishing vintage gun barrels by machining their inner damaged layer and replacing it by an intact, autofrettaged, shrink-fit liner that will restore the barrel to its original performance. The design of the shrink-fitted liner is based on two design principles. First, the von-Mises residual stress distribution through the thickness of the barrel at each of its cross sections along the inserted liner should be at least equal in magnitude to von Mises stress, which prevailed in the original barrel. Second, once the maximum pressure is applied to the compound barrel, the von-Mises stresses at the inner surfaces of the liner machined barrel should be equal to their respective yield stresses. The preliminary results demonstrate the ability of this process to mend such barrels and bringing them back to their initial safe maximum pressure (SMP) and their intact conditions, rather than condemn them. Furthermore, from the authors' experience, based on a preliminary rough estimate, such an alternative seems to be cost effective.

Fluid-Structure Interaction Analysis of Flow-Induced Deformation in a Two-Phase, Neo-Hookean Marine Egg

2006 ◽  
Vol 128 (4) ◽  
pp. 519-526 ◽  
Author(s):  
T. Kim ◽  
C W. Wang ◽  
F. I. M. Thomas ◽  
A. M. Sastry
Keyword(s):  
Interaction Analysis ◽  
Von Mises Stress ◽  
Finite Element Analyses ◽  
Two Phase ◽  
Shear Moduli ◽  
Arbacia Punctulata ◽  
Structure Interaction ◽  
Material Parameters ◽  
Von Mises ◽  
Von Mises Stresses

Coupled computational fluid dynamics and finite element analyses were used to determine the material properties of the egg and jelly layer of the sea urchin Arbacia punctulata. Prior experimental shear flow results were used to provide material parameters for these simulations. A Neo-Hookean model was used to model the hyperelastic behaviors of the jelly layer and egg. A simple compressive simulation was then performed, to compare the maximum von Mises stresses within eggs, with and without jelly layers. Results of this study showed that (1) shear moduli range from ∼100to160Pa, and ∼40to140Pa for an egg without a jelly layer, and jelly layer itself, respectively; and (2) the presence of the jelly layer significantly reduces maximum von Mises stress in an egg undergoing compression.

Trans-Thrombus Blood Pressure Effects in Abdominal Aortic Aneurysms

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Clark A. Meyer ◽  
Carine Guivier-Curien ◽  
James E. Moore
Keyword(s):  
Wall Stress ◽  
Aortic Aneurysms ◽  
Pressure Effects ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Aneurysm Wall ◽  
Abdominal Aortic ◽  
Histopathological Studies ◽  
Von Mises ◽  
Von Mises Stresses

How much and how the thrombus supports the wall of an abdominal aortic aneurysm (AAA) is unclear. While some previous studies have indicated that thrombus lacks the mechanical integrity to support much load compared with the aneurysm wall, others have shown that removing thrombus in computational AAA models drastically changes aneurysm wall stress. Histopathological studies have shown that thrombus properties vary through the thickness and it can be porous. The goal of this study is to explore the variations in thrombus properties, including the ability to isolate pressure from the aneurysm wall, incomplete attachment, and their effects on aneurysm wall stress, an important parameter in determining risk for rupture. An analytical model comprised of cylinders and two patient specific models were constructed with pressurization boundary conditions applied at the lumen or the thrombus/aneurysm wall interface (to simulate complete transmission of pressure through porous thrombus). Aneurysm wall stress was also calculated in the absence of thrombus. The potential importance of partial thrombus attachment was also analyzed. Pressurizing at either surface (lumen versus interface) made little difference to mean von Mises aneurysm wall stress values with thrombus completely attached (3.1% analytic, 1.2% patient specific) while thrombus presence reduced mean von Mises stress considerably (79% analytic, 40–46% patient specific) in comparison to models without it. Peak von Mises stresses were similarly influenced with pressurization surface differing slightly (3.1% analytic, 1.4% patient specific) and reductions in stress by thrombus presence (80% analytic, 28–37% patient specific). The case of partial thrombus attachment was investigated using a cylindrical model in which there was no attachment between the thrombus and aneurysm wall in a small area (10 deg). Applying pressure at the lumen resulted in a similar stress field to fully attached thrombus, whereas applying pressure at the interface resulted in a 42% increase in peak aneurysm wall stress. Taken together, these results show that the thrombus can have a wall stress reducing role even if it does not shield the aneurysm wall from direct pressurization—as long as the thrombus is fully attached to the aneurysm wall. Furthermore, the potential for porous thrombus to transmit pressure to the interface can result in a considerable increase in aneurysm wall stress in cases of partial attachment. In the search for models capable of accurately assessing the risk for rupture, the nature of the thrombus and its attachment to the aneurysm wall must be carefully assessed.

scholarly journals Influence of sagittal root positions on the stress distribution around custom-made root-analogue implants: a three-dimensional finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chunping Lin ◽  
Hongcheng Hu ◽  
Junxin Zhu ◽  
Yuwei Wu ◽  
Qiguo Rong ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Class I ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Custom Made ◽  
Root Position ◽  
Von Mises ◽  
Von Mises Stresses

Abstract Background Stress concentration may cause bone resorption even lead to the failure of implantation. This study was designed to investigate whether a certain sagittal root position could cause stress concentration around maxillary anterior custom-made root-analogue implants via three-dimensional finite element analysis. Methods The von Mises stresses in the bone around implants in different groups were compared by finite element analysis. Six models were constructed and divided into two groups through Geomagic Studio 2012 software. The smooth group included models of unthreaded custom-made implants in Class I, II or III sagittal root positions. The threaded group included models of reverse buttress-threaded implants in the three positions. The von Mises stress distributions and the range of the stresses under vertical and oblique loads of 100 N were analyzed through ANSYS 16.0 software. Results Stress concentrations around the labial lamella area were more prominent in the Class I position than in the Class II and Class III positions under oblique loading. Under vertical loading, the most obvious stress concentration areas were the labial lamella and palatal apical areas in the Class I and Class III positions, respectively. Stress was relatively distributed in the labial and palatal lamellae in the Class II position. The maximum von Mises stresses in the bone around the custom-made root-analogue implants in this study were lower than around traditional implants reported in the literature. The maximum von Mises stresses in this study were all less than 25 MPa in cortical bone and less than 6 MPa in cancellous bone. Additionally, compared to the smooth group, the threaded group showed lower von Mises stress concentration in the bone around the implants. Conclusions The sagittal root position affected the von Mises stress distribution around custom-made root-analogue implants. There was no certain sagittal root position that could cause excessive stress concentration around the custom-made root-analogue implants. Among the three sagittal root positions, the Class II position would be the most appropriate site for custom-made root-analogue implants.

scholarly journals Effects of the geometric shape and placing length of a fiber post on the stress distribution in a mandibular premolar tooth: A finite element analysis study

2018 ◽  
Vol 8 (3) ◽  
pp. 105-110
Author(s):  
Tuğrul Aslan ◽  
Emir Esim ◽  
Kerem Kılıç ◽  
Özgür Er ◽  
Şahin Yıldırım
Keyword(s):  
Stress Distribution ◽  
Von Mises Stress ◽  
Fiber Post ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Fiber Posts ◽  
Luting Cement ◽  
Circular Fiber ◽  
Von Mises ◽  
Von Mises Stresses

Aim: The aim of this study was to evaluate the effects of two geometrically different fiber post systems and two different placing lengths on the stress distribution of endodontically treated teeth. Methodology: Four different mandibular premolar tooth models were created. These models were restored using oval or circular fiber posts with two different placing lengths. An oblique force of 300 N was applied to the top of the tooth, and von Mises stress evaluations were carried out on the dentin tissue, luting cement, and fiber posts. Results: The maximum von Mises stresses were observed in the 10-mm long circular fiber post model, while the minimum stresses were seen in the 5-mm long oval fiber post model. In general, the oval fiber post models presented more homogeneous stresses than the circular fiber post models. Moreover, the 10-mm long fiber post models generated greater von Mises stresses than the 5-mm long fiber post models in the dentin tissue and luting cement. Conclusion: According to the study findings, the use of oval fiber posts at both placing lengths is suggested for oval shaped root canals due to the lower stress concentrations.

scholarly journals FINITE ELEMENT ANALYSIS USING SHELL ELEMENTS ON RETICULATED STRUCTURES

2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Alexandre Huberto Balbino Selhorst ◽  
Rafael Elias Meyer ◽  
Tatielen Pereira Costa ◽  
Liércio André Isoldi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Von Mises Stress ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Shell Elements ◽  
Final Weight ◽  
Verification Process ◽  
Von Mises ◽  
Von Mises Stresses

This paper studies the possibility of using SHELL elements on structures that are usually designed using BEAM or BAR elements. Using SHELL elements in such structures, named reticulated structures, opens the possibility to remove material from the structures’ members by adding holes. Once the members get holes, the final weight of the structure and material consumption will drop. In order to develop the study, a total of three different structures were analyzed using the software ANSYS®. This software uses the Finite Element Method to solve the equations originated from the designed structure upon it is meshed and the boundary conditions are set. Several results between SHELL and SOLID elements for each one of the structures were compared. The comparison of SHELL model with a SOLID model is used as a verification process, for SOLID elements are known to return accurate values. All of the meshes were tested by the independence mesh study to check its convergence. It is shown that the results are in a very good acceptable range with differences no bigger than 0.1 mm for displacements, and the map of von Mises stresses are pretty similar. Von Mises stresses for Finite Element Analysis for the C-Shaped Truss are shown in a figure comparing the results between the two finite elements used. This figure shows that there are no major differences between the SHELL and SOLID analyses. The Finite Element Analyses results were compared to analytical solutions, also. In this case, a noticeable difference in one structure for von Mises Stress was found. This difference, however, is understandable and reasonable, given the works presented on this paper.

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