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.

scholarly journals An elastoplastic finite element study of cylindrical plane-strain contact for steel/steel and Inconel 617/Incoloy 800H undergoing unidirectional sliding

2019 ◽  
Vol 234 (1) ◽  
pp. 126-133
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Coefficient Of Friction ◽  
Tangential Force ◽  
Leading Edge ◽  
Effective Coefficient ◽  
Incoloy 800H ◽  
Inconel 617 ◽  
Von Mises ◽  
Sliding Distance

The current work employs a two-dimensional plane strain finite element analysis to investigate the unidirectional sliding contact between a deformable half-cylinder and a deformable flat block. The unidirectional sliding is governed by a displacement-controlled action where the materials of the two contacting bodies are first set to identical steels at 20 ℃ and then to Inconel 617 and Incoloy 800H at 800 ℃. First, a normal interference (indentation) is applied, which is followed by unidirectional sliding. The von Mises stress distribution, plastic strain distribution, junction growth, normal force, tangential force, effective coefficient of friction, and scars on the surface of the block are obtained during the sliding motion. The leading edge of the contacting area and the bulk material under the leading edge experience large von Mises stresses. The large plastic strain is found on the surface of the block, and forms a “pocket” shape under the surface. The junction growth is also investigated, showing the direction of the growth is in the same direction of the tangential force that the weaker material experiences. The forces and the effective coefficient of friction are found to stabilize after a certain sliding distance, and the effective coefficient of friction converges to the coefficient of friction used in the model. Pileup is found on the surface of the block after a sufficient unidirectional sliding distance.

An Elastoplastic Finite Element Study of Displacement-Controlled Fretting in a Plane-Strain Cylindrical Contact

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Tangential Force ◽  
Ductile Material ◽  
Finite Element Study ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Element Study

This work presents a finite element study of a two-dimensional (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 the same material properties (specifically steel), however, because the results are normalized, they can characterize a range of contact scales (micro to macro), and are applicable for ductile material pairs that behave in an elastic-perfectly plastic manner. Different coefficients of friction (COFs) are used in 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 there when the COFs are sufficiently large. In addition, junction growth is investigated, showing a magnitude that increases with the COF, while the rate of growth stabilization decreases with the COF. 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 reported experimental results. The effects of boundary conditions are also discussed where a prestressed compressed block is found to improve (i.e., reduce) the magnitude of the plastic strain compared to an unstressed block.

scholarly journals Reconstruction of Severe Acetabular Bone Defect with 3D Printed Ti6Al4V Augment: A Finite Element Study

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jun Fu ◽  
Ming Ni ◽  
Jiying Chen ◽  
Xiang Li ◽  
Wei Chai ◽  
...  
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Bone Defect ◽  
Cancellous Bone ◽  
Acetabular Bone ◽  
Fea Model ◽  
Acetabular Bone Defect ◽  
3D Printed ◽  
Von Mises ◽  
Von Mises Stresses

Purpose. The purpose of this study was to establish the finite element analysis (FEA) model of acetabular bone defect reconstructed by 3D printed Ti6Al4V augment and TM augment and further to analyze the stress distribution and clinical safety of augments, screws, and bones.Methods. The FEA model of acetabular bone defect reconstructed by 3D printed Ti6Al4V augment was established by the CT data of a patient with Paprosky IIIA defect. The von Mises stresses of augments, screws, and bones were analyzed by a single-legged stance loading applied in 3 increments (500 N, 2000 N, and 3000 N).Results. The peak von Mises stresses under the maximal loading in the 3D printed augments, screws, and cortical bone were less than the yield strength of the corresponding component. However, the peak stress in the bone was greater than the yield strength of cancellous bone under walking or jogging loading. And under the same loading, the peak compressive and shear stresses in bone contact with TM augment were larger than these with 3D printed augment.Conclusions. The FEA results show that all the components will be intact under single-legged standing. However, partial cancellous bone contacted with 3D printed augment and screws will lose efficacy under walking or jogging load. So we recommend that patients can stand under full bearing, but can not walk or jog immediately after surgery.

A Finite Element Analysis of the Human Temporomandibular Joint

1994 ◽  
Vol 116 (4) ◽  
pp. 401-407 ◽  
Author(s):  
J. Chen ◽  
Liangfeng Xu
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Reaction Force ◽  
Element Model ◽  
Contact Stresses ◽  
Element Analysis ◽  
Tensile Stresses ◽  
Reaction Forces ◽  
Von Mises ◽  
Von Mises Stresses

A 2-D finite element model of the human temporomandibular joint (TMJ) has been developed to investigate the stresses and reaction forces within the joint during normal sagittal jaw closure. The mechanical parameters analyzed were maximum principal and von Mises stresses in the disk, the contact stresses on the condylar and temporal surfaces, and the condylar reactions. The model bypassed the complexity of estimating muscle forces by using measured joint motion as input. The model was evaluated by several tests. The results demonstrated that the resultant condylar reaction force was directed toward the posterior side of the eminence. The contact stresses along the condylar and temporal surfaces were not evenly distributed. Separations were found at both upper and lower boundaries. High tensile stresses were found at the upper boundaries. High tensile stresses were found at the upper boundary of the middle portion of the disk.

Vertical tail FEA with a CAD/CAE based multidisciplinary process

2018 ◽  
Vol 90 (4) ◽  
pp. 652-658
Author(s):  
Péter Deák
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Tail Length ◽  
Element Model ◽  
Point Of View ◽  
Content Type ◽  
Nodal Displacements ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Aided Design

Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

An experimental-nonlinear finite element study of a balloon expandable stent inside a realistic stenotic human coronary artery to investigate plaque and arterial wall injury

2015 ◽  
Vol 60 (6) ◽  
Author(s):  
Alireza Karimi ◽  
Reza Razaghi ◽  
Ahmad Shojaei ◽  
Mahdi Navidbakhsh
Keyword(s):  
Finite Element ◽  
Arterial Wall ◽  
Material Model ◽  
Nonlinear Finite Element ◽  
Outer Side ◽  
Human Coronary Artery ◽  
Stent Expansion ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Angioplasty And Stenting

AbstractThe stresses induced within plaque tissues and arterial layers during stent expansion inside an atherosclerotic artery can be exceeded from the yield stresses of those tissues and, consequently, lead to plaque or arterial wall rupture. The distribution and magnitude of the stresses in the plaque-artery-stent structure might be distinctly different for different plaque types. In this study, the mechanical properties of six healthy and atherosclerotic human coronary arteries were determined for application in plaque and arterial vulnerability assessment. A nonlinear finite element simulation based on an Ogden material model was established to investigate the effect of plaque types on the stresses induced in the arterial wall during implantation of a balloon expandable coronary stent. The atherosclerotic artery was assumed to consist of a plaque and normal arterial tissues on its outer side. The results indicated a significant influence of plaque types on the maximum stresses induced within the plaque wall and arterial wall during stenting but not when computing maximum stress on the stent. The stress on the stiffest calcified plaque wall was 3.161 MPa, whereas cellular and hypocellular plaques showed relatively less stress on their wall. The highest von Mises stresses within the arterial wall were observed on the hypocellular plaque, whereas the lowest stresses were seen to be located in the calcified and cellular plaques. Although the computed stresses on the arterial wall for the calcified and cellular plaques were not high enough to invoke a rupture, the stress on the hypocellular plaque was relatively higher than that of the strength of the arterial wall. These findings may have implications not only for understanding the stresses induced in plaque and the arterial wall, but also for developing surgeries such as balloon-angioplasty and stenting.

scholarly journals Effect of Augmentation Material Stiffness on Adjacent Vertebrae after Osteoporotic Vertebroplasty Using Finite Element Analysis with Different Loading Methods

2015 ◽  
Vol 6;18 (6;11) ◽  
pp. E1101-E1110
Author(s):  
Ah-Reum Cho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Cement ◽  
Vertebral Fractures ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Adjacent Vertebral Body ◽  
Von Mises ◽  
Von Mises Stresses

Background: Vertebroplasty is an effective treatment for osteoporotic vertebral fractures, which are one of the most common fractures associated with osteoporosis. However, clinical observation has shown that the risk of adjacent vertebral body fractures may increase after vertebroplasty. The mechanism underlying adjacent vertebral body fracture after vertebroplasty is not clear; excessive stiffness resulting from polymethyl methacrylate has been suspected as an important mechanism. Objectives: The aim of our study was to compare the effects of bone cement stiffness on adjacent vertebrae after osteoporotic vertebroplasty under load-controlled versus displacementcontrolled conditions. Study Design: An experimental computer study using a finite element analysis. Setting: Medical research institute, university hospital, Korea. Methods: A three-dimensional digital anatomic model of L1/2 bone structure was reconstructed from human computed tomographic images. The reconstructed three-dimensional geometry was processed for finite element analysis such as meshing elements and applying material properties. Two boundary conditions, load-controlled and displacement-controlled methods, were applied to each of 5 deformation modes: compression, flexion, extension, lateral bending, and torsion. Results: The adjacent L1 vertebra, irrespective of augmentation, revealed nearly similar maximum von Mises stresses under the load-controlled condition. However, for the displacementcontrolled condition, the maximum von Mises stresses in the cortical bone and inferior endplate of the adjacent L1 vertebra increased significantly after cement augmentation. This increase was more significant than that with stiffer bone cement under all modes, except the torsion mode. Limitations: The finite element model was simplified, excluding muscular forces and incorporating a large volume of bone cement, to more clearly demonstrate effects of bone cement stiffness on adjacent vertebrae after vertebroplasty. Conclusion: Excessive stiffness of augmented bone cement increases the risk of adjacent vertebral fractures after vertebroplasty in an osteoporotic finite element model. This result was most prominently observed using the displacement-controlled method. Key words: Bone cements, displacement-controlled method, finite element analysis, loadcontrolled method, osteoporosis, osteoporotic fracture, polymethyl methacrylate, vertebroplasty

scholarly journals Assessing the Impact of Changes on Design and Material of Howe Bridges by Finite Element Analysis

2021 ◽  
Vol 3 (3) ◽  
pp. 33-37
Author(s):  
Jairo Aparecido Martins ◽  
Estaner Claro Romão
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Lateral Loads ◽  
Element Analysis ◽  
Design Changes ◽  
Minimal Design ◽  
Von Mises ◽  
Truss Bridge ◽  
Von Mises Stresses ◽  
The Impact

This paper presents an investigation of changes on design and material of a Howe bridge under vertical loads. Specifically, it aimed to find out how small changes on Howe bridge design and material affected von Mises stresses as well as stresses at Z direction. As a method, it was used a finite element analysis (linear-elastic) by Autodesk F-360. Half of a bridge was designed (one bridge side) and loaded with a central higher load and two equal smaller lateral loads. In essence, von Mises stresses (s) and stress at Z direction (sz) decreased on stresses values until a certain design change, which was proportional to a raise of mass due to beams added on the trusses. With a change of material to a lighter metal, from steel to aluminum, it was possible to overcome the mass drawback brought by steel and utterly possible to end up for a more effective design for a Howe truss bridge by applying minimal design changes.

Biomechanical evaluation of the screw preload values used in the plate placement for bone fractures

2020 ◽  
pp. 095441192096462
Author(s):  
Talip Çelik
Keyword(s):  
Finite Element ◽  
Bone Fractures ◽  
Bone Plate ◽  
Long Bone ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Biomechanical Evaluation ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Plate System

The purpose of this study is to examine the effects of screw preload values on the bone-plate system. The preload value was taken differently in the literature range from 50 N to 3000 N. These preload value were examined in this study. The finite element method was used to calculate the strain and stress on the models. The long bone, plate and screws were modeled as 3D using CAD software. The finite element models were created using Ansys Workbench software. The convergence and validation study were made for the correct results. The 400 N axial load was applied to the proximal end of bone. The distal end of the bone fixed for boundary condition. The preload values were applied to the screws differently. The results of the finite element analysis were compared and evaluated. The results showed that when the preload values increased, the von Mises stresses and strains on the bone and plate system increased. The critical preload value of the screw is the 500 N. The upper values of this critical value can be damaged bone and plate system. The critical region of the bone is the holes where the screw inserted. In conclusion, the preload values of the screw should not exceed the 500 N for the successful fixation.

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