Study of Different Biomaterials for Artificial Lumbar Disc Prosthesis Using FEM

The purpose of this study was to analyze the behavior of a lumbar spine disc prosthesis with different materials. The study was performed at L4-L5 lumbar motion segment using the finite element method (FEM). A healthy Finite Element (FE) model was used as a reference with which to compare the results of the FE simulations of the artificial discs. The healthy and the artificial FE models were subjected to a combination of 0.5 MPa Compression pre-load and 10Nm of Flexion moment. The artificial FE models were based on Maverick artificial disc, and the three materials proposed for study the artificial disk were Titanium, Ceramic and CrCoMo alloy. The most suitable material for developed the artificial disc was the CoCrMo alloy due to: The von Mises stresses on the bone with which this artificial disc was in contact were reduced as much as possible and also, were very similar to the von Mises stresses obtained in the bones from the healthy disc.

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Finite element simulations of the effects of an extraoral device, RAMPA, on anterosuperior protraction of the maxilla and comparison with gHu-1 intraoral device

The Angle Orthodontist ◽

10.2319/020521-106.1 ◽

2021 ◽

Author(s):

Mohammad Moshfeghi ◽

Yasushi Mitani ◽

Bumkyoo Choi ◽

Peiman Emamy

Keyword(s):

Finite Element ◽

Fe Model ◽

Maxillary Expansion ◽

Lateral Direction ◽

Positive Effects ◽

Intraoral Device ◽

Nodal Displacements ◽

Von Mises ◽

External Forces ◽

Von Mises Stresses

ABSTRACT Objectives To investigate the effects of an extraoral device, right-angle maxillary protraction appliance (RAMPA), combined with a semi-rapid maxillary expansion intraoral device (gHu-1) on the anterosuperior protraction of maxillary bone. Materials and Methods The finite element (FE) model included craniofacial bones and all sutures. The linear assumption was assumed for the FE simulations and the material properties of bones and sutures. The gHu-1 was simulated under screw activations equal to Δx = 0.25 and 0.5 mm in the lateral direction with and without RAMPA under a set of external forces {F1 = 2.94, F2 = 1.47, F3 = 4.44} N. Results Displacement contours, nodal displacements of 12 landmarks, and von Mises stresses were compared. Combining RAMPA and gHu-1 (with Δx = 0.25 mm) resulted in changes in the displacement of the front part of the maxilla near the mid-palatal suture from (0.02, −0.1, −0.02) mm to (0.02, 0.3, 0.8) mm. For gHu-1 with Δx = 0.5 mm, the displacement of the same part changed from (0.04, −0.04, −0.2) mm to (0.04, 0.3, 0) mm. Similar trends were found in other locations. Conclusions The findings are in agreement with the previous cephalometric clinical data of an 8-year-old patient and prove the positive effects of RAMPA on the anterosuperior protraction of the maxilla when it is combined with the intraoral device gHu-1. In addition, RAMPA does not interfere with the lateral expansion generated by the intraoral device.

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

BioMed Research International ◽

10.1155/2018/6367203 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 3

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.

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Finite Element Analysis of In-Plane Displacements and Von-Mises Stresses in Ellipsoidal and Circular Cylinderical Petroleum Tankers

Engineering ◽

10.4236/eng.2013.52024 ◽

2013 ◽

Vol 05 (02) ◽

pp. 167-177

Author(s):

Oluleke Oluwole ◽

Eyere Emagbetere

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Element Analysis ◽

Von Mises ◽

Von Mises Stresses

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A Finite Element Analysis of the Human Temporomandibular Joint

Journal of Biomechanical Engineering ◽

10.1115/1.2895790 ◽

1994 ◽

Vol 116 (4) ◽

pp. 401-407 ◽

Cited By ~ 71

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.

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Vertical tail FEA with a CAD/CAE based multidisciplinary process

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-11-2016-0212 ◽

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.

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

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650118788755 ◽

2018 ◽

Vol 233 (4) ◽

pp. 553-569 ◽

Cited By ~ 2

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.

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

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519415500256 ◽

2015 ◽

Vol 15 (03) ◽

pp. 1550025 ◽

Cited By ~ 1

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.

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A Novel Rat Model of Orthodontic Tooth Movement Using Temporary Skeletal Anchorage Devices: 3D Finite Element Analysis andIn VivoValidation

International Journal of Dentistry ◽

10.1155/2014/917535 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Neelambar Kaipatur ◽

Yuchin Wu ◽

Samer Adeeb ◽

Thomas Stevenson ◽

Paul Major ◽

...

Keyword(s):

Finite Element ◽

Alveolar Bone ◽

Tooth Movement ◽

Orthodontic Tooth Movement ◽

Von Mises Stress ◽

Fe Model ◽

Sprague Dawley ◽

Element Analysis ◽

Von Mises ◽

The Right

The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built usingμCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. Forin vivovalidation of the FE model, Sprague-Dawley rats (n=25) were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs.

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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

Biomedical Engineering / Biomedizinische Technik ◽

10.1515/bmt-2014-0144 ◽

2015 ◽

Vol 60 (6) ◽

Cited By ~ 7

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.

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