scholarly journals Kyphoplasty of Osteoporotic Fractured Vertebrae: A Finite Element Analysis about Two Types of Cement

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Carolin Meyer ◽  
Kerstin van Gaalen ◽  
Tim Leschinger ◽  
Max J. Scheyerer ◽  
Wolfram F. Neiss ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vertebral Body ◽  
Lumbar Vertebrae ◽  
Von Mises Stress ◽  
Vertebral Compression Fractures ◽  
Stress Concentrations ◽  
Lower Stress ◽  
Element Analysis ◽  
Von Mises

If conservative treatment of osteoporotic vertebral compression fractures fails, vertebro- or kyphoplasty is indicated. Usually, polymethylmethacrylate cement (PMMA) is applied coming along with many disadvantageous features. Aluminum-free glass-polyalkenoate cement (GPC) appears to be a benefit alternative material. This study aimed at comparing the mean stress values in human vertebrae after kyphoplasty with PMMA and GPC (IlluminOss™) at hand of a finite element analysis. Three models were created performing kyphoplasty using PMMA or IlluminOss™, respectively, at two native, human lumbar vertebrae (L4) while one remains intact. Finite element analysis was performed using CT-scans of every vertebra. Moreover the PMMA-treated vertebra was used as a model as analyses were executed using material data of PMMA and of GPC. The unimpaired, spongious bone showed potentials of 0.25 MPa maximally. After augmentation stress levels showed fivefold increase, rising from externally to internally, revealing stress peaks at the ventral border of the spinal canal. At central areas of cement 1 MPa is measured in both types of cement. Around these central areas the von Mises stress decreased about 25-50% (0.5-0.75 MPa). If workload of 500 N was applied, the stress appeared to be more centralized at the IlluminOss™-model, similar to the unimpaired. Considering the endplates the GPC model also closely resembles the unimpaired. Comparing the PMMA-treated vertebral body and the GPC-simulation, there is an obvious difference. While the PMMA-treated model showed a central stress peak of 5 MPa, the GPC-simulation of the same vertebral body presents lower stress of 1.2-2.5 MPa. Finite element analysis showed that IlluminOss™ (GPC), used in kyphoplasty of vertebral bodies, creates lower level stress and strain compared to standardly used PMMA, leading to lower stress concentrations on the cranial and caudal vertebral surface especially. GPC appears to own advantageous biological and clinical relevant features.

Comparison of Torque Transmitting Shaft Connectivity Using a Trilobe Polygon Connection and an Involute Spline

2000 ◽  
Vol 122 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Zella L. Kahn-Jetter ◽  
Eugene Hundertmark ◽  
Suzanne Wright
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
The Other ◽  
Von Mises Stress ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Principal Compressive Stress ◽  
Torque Transmission ◽  
Von Mises ◽  
Involute Spline

The results of a finite element analysis of a trilobe polygon shaft connection used as an alternative for a spline for torque transmission is presented. These results are compared to the results of a finite element analysis previously performed on an involute spline. It is shown that the tensile stress in the polygon shaft is significantly smaller than in the involute spline and is smaller than all the other stresses in both the shaft and the hub in the polygon connection. Furthermore, the magnitudes and distributions of the maximum principal compressive stress, the shear stress, and the Von Mises stress are nearly the same on the shaft and the hub. It appears that polygonal connections can be more advantageous than splined connections because of lower stresses and the lack of stress concentrations typical of splines. [S1050-0472(00)00601-2]

Finite element analysis of endodontically treated tooth restored with different posts under thermal and mechanical loading

2011 ◽  
Vol 1 (3) ◽  
pp. 75 ◽  
Author(s):  
Ozkan ADIGÜZEL ◽  
Senem YİĞİT ÖZER ◽  
Emrullah BAHŞİ ◽  
İzzet YAVUZ
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Loading ◽  
Maximum Stress ◽  
Von Mises Stress ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Endodontically Treated Tooth ◽  
Von Mises ◽  
Titanium Post

Aim: This study compared the stress distributions of endodontically treated tooth restored with carbon and titanium post under thermal and mechanical loading conditions. Methodology: A 3-dimensional finite element model was created to represent in a labiolingual cross-sectional view of an endodontically treated maxillary central incisor tooth with its supporting structures. It was modified according to two post systems with different physical properties consisting titanium, and carbon fiber. Stress distribution and stress values were then calculated by considering the three dimensional von Mises stress criteria. Results: A 100-N static vertical occlusal load was applied on the node at the center of occlusal surface of the tooth. The von Mises stress values for carbon post model was on the coronal third and the cervical area of the root in the range of 436,16 and 3,59 MPa,  for titanium post model was 590,55 and 3,05 MPa. Thermal stress values for carbon post model showed that maximum stress concentrations were noted on the coronal third and the top of the post area of the root in the range of 509,94 and 6,38 MPa. Titanium post model showed that maximum stress concentrations were noted on the coronal third and top of the post area of the root in the range of 1165,06 and 3,06 MPa. Conclusion: This study shows that the titanium post yields larger stresses than the carbon post under thermal conditions.  How to cite this article: Adıgüzel Ö, Yiğit Özer S, Bahşi E, Yavuz İ. Finite element analysis of endodontically treated tooth restored with different posts under thermal and mechanical loading. Int Dent Res 2011;3:75-80. Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

scholarly journals 3D Finite Element Analysis of Rotary Instruments in Root Canal Dentine with Different Elastic Moduli

2021 ◽  
Vol 11 (6) ◽  
pp. 2547 ◽  
Author(s):  
Carlo Prati ◽  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Alexandre Luiz Souto Borges ◽  
Maurizio Ventre ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Root Canal ◽  
Elastic Moduli ◽  
Reaction Force ◽  
Von Mises Stress ◽  
Elastic Behavior ◽  
Element Analysis ◽  
Heat Treated ◽  
Von Mises

The aim of the present investigation was to calculate the stress distribution generated in the root dentine canal during mechanical rotation of five different NiTi endodontic instruments by means of a finite element analysis (FEA). Two conventional alloy NiTi instruments F360 25/04 and F6 Skytaper 25/06, in comparison to three heat treated alloys NiTI Hyflex CM 25/04, Protaper Next 25/06 and One Curve 25/06 were considered and analyzed. The instruments’ flexibility (reaction force) and geometrical features (cross section, conicity) were previously investigated. For each instrument, dentine root canals with two different elastic moduli(18 and 42 GPa) were simulated with defined apical ratios. Ten different CAD instrument models were created and their mechanical behaviors were analyzed by a 3D-FEA. Static structural analyses were performed with a non-failure condition, since a linear elastic behavior was assumed for all components. All the instruments generated a stress area concentration in correspondence to the root canal curvature at approx. 7 mm from the apex. The maximum values were found when instruments were analyzed in the highest elastic modulus dentine canal. Strain and von Mises stress patterns showed a higher concentration in the first part of curved radius of all the instruments. Conventional Ni-Ti endodontic instruments demonstrated higher stress magnitudes, regardless of the conicity of 4% and 6%, and they showed the highest von Mises stress values in sound, as well as in mineralized dentine canals. Heat-treated endodontic instruments with higher flexibility values showed a reduced stress concentration map. Hyflex CM 25/04 displayed the lowest von Mises stress values of, respectively, 35.73 and 44.30 GPa for sound and mineralized dentine. The mechanical behavior of all rotary endodontic instruments was influenced by the different elastic moduli and by the dentine canal rigidity.

Investigating the Calibration Curves for a Two Component Cutting Tool Lathe Dynamometer Using Finite Element Analysis

2016 ◽  
Vol 24 ◽  
pp. 71-84
Author(s):  
Osezua Obehi Ibhadode ◽  
Ishaya Musa Dagwa ◽  
Akii Okonigbon Akhaehomen Ibhadode
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cutting Tool ◽  
Von Mises Stress ◽  
Equation Modeling ◽  
Element Analysis ◽  
Calibration Curves ◽  
Two Component ◽  
Applied Forces ◽  
Von Mises

Calibration curves of a multi-component dynamometer is of essence in machining operations in a lathe machine as they serve to provide values of force and stress components for cutting tool development and optimization. In this study, finite element analysis has been used to obtain the deflection and stress response of a two component cutting tool lathe dynamometer, for turning operation, when the cutting tool is subjected to cutting and thrust forces from 98.1N to 686.7N (10 to 70kg-wts), at intervals of 98.1N(10kg-wt). By obtaining the governing equation, modeling the dynamometer assembly, defining boundary conditions, generating the assembly mesh, and simulating in Inventor Professional; horizontal and vertical components of deflection by the dynamometer were read off for three different loading scenarios. For these three loading scenarios, calibration plots by experiment compared with plots obtained from simulation by finite element analysis gave accuracies of 79%, 95%, 84% and 36%, 57%, 63% for vertical and horizontal deflections respectively. Also, plots of horizontal and vertical components of Von Mises stress against applied forces were obtained.

scholarly journals Simulasi Kekuatan Mekanik Sudu Turbin Angin Horizontal Menggunakan Software Simscale

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Mubni Nazar ◽  
Anggito Pringgo Tetuko ◽  
Djuhana Djuhana
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Penelitian ini dilakukan untuk meningkatkan koefisien daya yang maksimal. Salah satunya dengan mengunakan kualitas sudu yang baik. Untuk mengoptimalkan fungsi turbin angin penulis menggunakan material sudu pada turbin angin dengan menggunakan Acrylonitrine Butadine Styrene (ABS). Oleh karena itu pada penelitian ini metode yang digunakan adalah metode Finite Element Analysis Simulasi yang dipilih adalah dynamic. Penelitian ini adalah pengujian kekuatan sudu turbin angin horizontal dengan variasi kecepatan angin 10 – 20 m/s ditinjau dari von mises stress dan displacement. Dari hasil simulasi kecepatan angin memiiki pengaruh terhadap distribusi stress dan displacement. Material yang digunakan masih berada di bawah batas kekuatan material, semakin besar gaya yang diberikan semakin besar nilai stress dan displacement. Pada hasil simulasi didapatkan nilai stress minimum 5.8 Pa stress maksimum 22.94 Sedangkan dalam pengujian displacement dihasilkan nilai minimum 1.27 m displacement maksimum 4.99 m.

scholarly journals Is Perpendicular Double Two-Hole Plates Fixation Superior to Single Four-Hole Plate Fixation to Treat Mandibular Symphysis Fracture?—A Finite Element Study

2021 ◽  
Vol 11 (18) ◽  
pp. 8629
Author(s):  
Li-Ren Chang ◽  
Ya-Pei Hou ◽  
Ting-Sheng Lin
Keyword(s):  
Finite Element ◽  
Plate Fixation ◽  
Mandibular Condyle ◽  
Fracture Site ◽  
Von Mises Stress ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Mandibular Symphysis ◽  
Lower Border ◽  
Von Mises

The effectiveness of a single four-hole plate (S4HP), perpendicularly oriented four-hole and two-hole plate (Per4H2HP), and perpendicularly oriented double two-hole plate (PerD2HP) for the fixation of a mandibular fracture was studied. A finite element analysis of the mandibular symphysis fractures treated with S4HP, Per4H2HP, and PerD2HP was performed. All surface nodes were fixed in the mandibular condyle region and occlusal muscle forces were applied. The maximal von Mises stress (MaxVMS) values of the plates, screws and screw holes were investigated. The displacement of the fracture site on the lower border of the mandibular symphysis was recorded. The displacement on the lower border of the fracture sites in the S4HP group was greater than that in the Per4H2HP group and the PerD2HP group. There was no eversion at the fracture site among all groups. Both the S4HP and Per4H2HP groups showed stress concentrations on the screws close to the fracture site. The MaxVMS increased when the number of screw holes on the mandibular anterior lower border decreased. The displacement of the fracture site and eversion with Per4H2HP and PerD2HP were far lower than those with S4HP. PerD2HP is a stable and green fixation technique for mandibular symphysis fractures.

Investigation on stress distribution and pressure capacity of two-layer split high-pressure die based on finite element analysis

2019 ◽  
Vol 233 (14) ◽  
pp. 5048-5055
Author(s):  
Z Yi ◽  
WZ Fu ◽  
MZ Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Stress State ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Element Analysis ◽  
Round Cylinder ◽  
Von Mises ◽  
Supporting Ring

In order to obtain a higher pressure capacity for the high-pressure die with a larger sample cavity, two types of two-layer split dies with a round cylinder and a quadrate cylinder were designed based on the conventional belt-type die. Finite element analysis was performed to investigate the stress distributions and pressure capacities of the high-pressure dies using a derived Mohr–Coulomb criterion and the von Mises criterion for the cylinder and supporting rings, respectively. As predicted by the finite element analysis results, in the two-layer split dies with a round cylinder, the stress state of the cylinder can be only slightly improved; and the von Mises stress of the first layer supporting ring can be hardly decreased. However, in the two-layer split dies with a quadrate cylinder and sample cavity, the stress state of the cylinder can be remarkably improved. Simultaneously, the von Mises stress of the supporting rings, especially for the first-layer supporting ring, can be also effectively decreased. The pressure capacities of the two-layer split dies with a round cylinder and a quadrate cylinder are 16.5% and 63.9% higher with respect to the conventional belt-type die.

Finite element analysis (FEA) of polylactic acid/polypropylene carbonate (PLA/PPC) blends fixation plate for craniomaxillofacial surgery

2019 ◽  
Vol 10 (5) ◽  
pp. 678-691
Author(s):  
Intan Najwa Humaira Mohamed Haneef ◽  
Norhashimah Shaffiar ◽  
Yose Fachmi Buys ◽  
Abdul Malek Abd. Hamid
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Human Body ◽  
Healing Process ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Content Type ◽  
New Material ◽  
Fixation Plate ◽  
Von Mises

Purpose The internal fixation plate of bone fractures by using polylactic acid (PLA) has attracted the attention of many researchers, as it is biodegradable and biocompatible to the human body. However, its brittleness has led to implant fracture. On the contrary, polypropylene carbonate (PPC), which is also biodegradable and biocompatible, has an excellent elongation at break. The purpose of this paper is to compare the PLA fixation plate with the new fixation plate made up of PLA/PPC blends by using finite element analysis (FEA). Design/methodology/approach The mandible bone from CT data set and fixation plate was designed by using the MIMICS, Amira and Solidworks softwares. Abaqus software was used for FEA of PLA/PPC fixation plate applied on the fractured mandible bone. A model of mandibular bone with a fracture in the body was subjected to incisor load. The analysis was run to determine the von Mises stress, elongation of the fixation plate and the displacement of the fractured gap of PLA/PPC blends fixation plate. Findings The von Mises stress predicted that all the blend compositions were safe to be used as a fixation plate since the stress values were less than the yield strength. In addition, the stress value of the fixation plate was gradually decreased up to 20 percent when the amount of PPC increased to 30 percent. This indicates that the stress shielding effect was successfully reduced. The elongation of the fixation plate was gradually increased from 11.54 to 12.55 µm as the amount of PPC in the blends increased from 0 to 30 percent, thereby illustrating that the flexibility of the fixation plate was improved by the addition of PPC. Finally, the measured displacement of the fractured gap for all compositions of PLA/PPC blends fixation plate is less than 150 µm, which proves the likely success of fracture fixation by using the PLA/PPC blends. Research limitations/implications An optimum solution of PLA/PPC blends and another new material such as compatibilizer need to be introduced in the blends in order to improve the performance of PLA/PPC blends as a new material for a fixation plate. Besides, by using the same method of producing PLA/PPC blends, longer durations for in vitro degradation of PLA/PPC blends are essential to further understand the degradation behavior of the blends applied in the human body. Finally, it is also important to further test the mechanical strength of PLA/PPC blends during the degradation period to know the current strength of the implant in the healing process of the bone. Practical implications PLA fixation plate and screw can commercially be used in CMF surgery since they reduce cost because of the elimination of secondary surgery to remove the fixation plate and screw after the healing process. Social implications It is hoped that the advantages of this research will ensure the market of PLA product to continue expanding in medical application. Originality/value This study is one of the alternative ways for the biomedical researchers to improve the elongation break of PLA. Currently, many researchers focus on polymeric materials such as PLA, poly(glycolic) acid and polydioxanone blends, which were extensively being used in CMF surgery. However, the work on PLA/PPC blends to be used as one of the materials for the CMF fixation plate is very limited, if any. PPC, the proposed material for this research, will improve the mechanical performance of PLA fixation plate and screw to become more sustainable and flexible when applied on human mandible bone.

scholarly journals Effect of Fiber Posts on Stress Distribution of Endodontically Treated Upper Premolars: Finite Element Analysis

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1708 ◽  
Author(s):  
Maciej Zarow ◽  
Mirco Vadini ◽  
Agnieszka Chojnacka-Brozek ◽  
Katarzyna Szczeklik ◽  
Grzegorz Milewski ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Resin Composite ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Endodontically Treated Tooth ◽  
Maxillary Premolars ◽  
Von Mises

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial–occlusal–distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal–palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin.

The function(s) of bone ornamentation in the crocodylomorph osteoderms: a biomechanical model based on a finite element analysis

Paleobiology ◽  
2019 ◽  
Vol 45 (1) ◽  
pp. 182-200 ◽  
Author(s):  
François Clarac ◽  
Florent Goussard ◽  
Vivian de Buffrénil ◽  
Vittorio Sansalone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Von Mises Stress ◽  
Late Triassic ◽  
Mechanical Resistance ◽  
Apical Surface ◽  
Element Analysis ◽  
Physiological Functions ◽  
Von Mises

AbstractThis paper aims at assessing the influence of the bone ornamentation and, specifically, the associated loss of bone mass on the mechanical response of the crocodylomorph osteoderms. To this end, we have performed three-dimensional (3D) modeling and a finite element analysis on a sample that includes both extant dry bones and well-preserved fossils tracing back to the Late Triassic. We simulated an external attack under various angles on the apical surface of each osteoderm and further repeated the simulation on an equivalent set of smoothed 3D-modeled osteoderms. The comparative results indicated that the presence of an apical sculpture has no significant influence on the von Mises stress distribution in the osteoderm volume, although it produces a slight increase in its numerical score. Moreover, performing parametric analyses, we showed that the Young's modulus of the osteoderm, which may vary depending on the bone porosity, the collagen fiber orientation, or the calcification density, has no impact on the von Mises stress distribution inside the osteoderm volume. As the crocodylomorph bone ornamentation is continuously remodeled by pit resorption and secondary bone deposition, we assume that the apical sculpture may be the outcome of a trade-off between the bone mechanical resistance and the involvement in physiological functions. These physiological functions are indeed based on the setup of a bone superficial vessel network and/or the recurrent release of mineral elements into the plasma: heat transfers during basking and respiratory acidosis buffering during prolonged apnea in neosuchians and teleosaurids; compensatory homeostasis in response to general calcium deficiencies. On a general morphological basis, the osteoderm geometric variability within our sample leads us to assess that the global osteoderm geometry (whether square or rectangular) does not influence the von Mises stress, whereas the presence of a dorsal keel would somewhat reduce the stress along the vertical axis.

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