On the Effect of Screw Preload on the Stress Distribution of Mandibles During Segmental Defect Treatment Using an Additively Manufactured Hardware

2016 ◽  
Author(s):  
Amirhesam Amerinatanzi ◽  
Narges Shayesteh Moghaddam ◽  
Ahmadreza Jahadakbar ◽  
David Dean ◽  
Mohammad Elahinia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Fixation Device ◽  
Element Analysis ◽  
Porous Niti ◽  
The Finite Element Analysis ◽  
Low Stiffness ◽  
Von Mises

The most common method for mandibular reconstructive surgery is the use of a Ti-6Al-4V fixation device and a fibular double barrel graft. This highly stiff fixation hardware (E = 112 GPa) often shields the bone graft (E = 20 GPa) from carrying the load, which may result in bone resorption. Highly stiff Ti-6Al-4V fixation hardware is also likely to concentrate stress in the fixation plate or at screw threads, possibly leading to hardware cracking or screw pull-out. As a solution for that, we have proposed and studied the effect of using a low stiffness, porous NiTi fixation device [1–4]. Although the stress in the fixation device is increased, using such low stiffness fixation hardware, is preferable to have an even higher stress on the graft in order to minimize the risk of resorption or hardware failure. We assume that preloading screws allows them to better engage the fixation hardware with the plate and the surrounding bone and causes an increased von Mises stress. The fixation device can be patient-specific and additively manufactured, such that the shape would match the outer surface of the cortical bone. In this study, we modeled a healthy cadaver mandible via CT-derived 3D surface data. The mandible was virtually resected in the molar region (M1−3). The model simulated the result of reconstructive surgery under the highest chewing loading regime (i.e., 526 N on first right molar tooth [5, 6]) where reconstruction was done with either Ti-6Al-4V fixation hardware or patient specific, stiffness-matched, porous NiTi fixation hardware. The calibration of the material properties for this simulation was done using experimentally obtained data (DSC and compression tests) of Ni-rich NiTi bulk samples. The analyzed term in the finite element analysis was stress distribution in the cortical and cancellous bone. Porous NiTi fixation devices were also produced using Selective Laser Melting (SLM) using the geometry of the aforementioned cadaver mandible. In this paper we have studied the effect of additional torque or preload on the performance of the fixation plates. The finite element analysis demonstrated that applying a preload to the screws increased the stress on the bone. Under similar levels of applied preload, the porous NiTi fixation device showed an increased level of von Mises stress in the bone, particularly in the graft. Additionally, the analysis indicated the higher level of stress on the bone surrounding the screws for the case of using NiTi, which could contribute to increasing screw stability. The fabricated patient-specific fixation hardware not only matched the shape of cortical bone but also contained the level of porosity that defines the appropriate modulus of elasticity.

scholarly journals Stress Distribution Analysis of the Rectangular and Star-Blade for Plastic Crusher Machine Using Finite Element Analysis

2021 ◽  
Vol 2111 (1) ◽  
pp. 012015
Author(s):  
Nalendro Mataram ◽  
Sigiet Haryo Pranoto ◽  
Rizqi Ilmal Yaqin ◽  
Anis Siti Nurrohkayati ◽  
Noer Aden Bahry ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Waste ◽  
Von Mises Stress ◽  
Distribution Analysis ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Stress Result ◽  
Von Mises ◽  
Better Than

Abstract Recycling plastic waste can help reduce plastic waste, which is the world’s largest problem. The first solution is a plastic crusher machine, which converts plastic packaging into pellets, especially for plastics made from polyester, which is often used in bottle packaging. An integral part of the crushing machine is the crushing blade, which determines the design and analysis of the blade. The finite element analysis method is widely used in engineering analysis. Its results can provide useful information for the analysis of manufacturing processes. A rectangular blade and a star-shaped blade are the two types to consider. The analytical results obtained on the blade of the crusher machine in the rectangular shape that was given loads by 200 N, 400 N, and 600 N are 1.285 × 103 N/m2, 2.570 × 103 N/m2, and 3.855 × 103 N/m2, respectively. We obtained the displacements are 1.080 × 10-6 mm, 2.160 × 10-6 mm, and 3.241 × 10-6 mm, respectively. The maximum von mises stress result on consecutive star-shaped blades are 8.890 × 102 N/m2, 1.778 × 103 N/m2, and 2.667 × 103 N/m2. The displacement obtained are 1.211 × 10-6 mm, 2.422 × 10-6 mm, and 3.633 × 10-6 mm. The results of this analysis indicate that for the star blade, the shape is better than for the rectangular blade at the same time, and for the star blade, the stress is smaller than for the rectangular blade. Based on this simulation, the safety factor is 15, which means that it is more than 1, which means that it is safe.

scholarly journals A deep learning approach to estimate stress distribution: a fast and accurate surrogate of finite-element analysis

2018 ◽  
Vol 15 (138) ◽  
pp. 20170844 ◽  
Author(s):  
Liang Liang ◽  
Minliang Liu ◽  
Caitlin Martin ◽  
Wei Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deep Learning ◽  
Stress Distribution ◽  
Machine Learning Techniques ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Stress Distributions ◽  
Element Analysis ◽  
Von Mises

Structural finite-element analysis (FEA) has been widely used to study the biomechanics of human tissues and organs, as well as tissue–medical device interactions, and treatment strategies. However, patient-specific FEA models usually require complex procedures to set up and long computing times to obtain final simulation results, preventing prompt feedback to clinicians in time-sensitive clinical applications. In this study, by using machine learning techniques, we developed a deep learning (DL) model to directly estimate the stress distributions of the aorta. The DL model was designed and trained to take the input of FEA and directly output the aortic wall stress distributions, bypassing the FEA calculation process. The trained DL model is capable of predicting the stress distributions with average errors of 0.492% and 0.891% in the Von Mises stress distribution and peak Von Mises stress, respectively. This study marks, to our knowledge, the first study that demonstrates the feasibility and great potential of using the DL technique as a fast and accurate surrogate of FEA for stress analysis.

scholarly journals Similar stress repartition for a standard uncemented collared femoral stem versus a shortened collared femoral stem

SICOT-J ◽  
2021 ◽  
Vol 7 ◽  
pp. 58
Author(s):  
Cécile Batailler ◽  
Jobe Shatrov ◽  
Axel Schmidt ◽  
Elvire Servien ◽  
Jean Marc Puch ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Stem ◽  
Short Stem ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Significant Difference ◽  
The Finite Element Analysis ◽  
Von Mises ◽  
Short Stems

Introduction: The design of uncemented femoral stems for use in total hip arthroplasty has evolved. Several uncemented short stems have been developed with different bone fixations, shapes, or stem lengths. The literature analyzing the biomechanical performance of short to standard stem lengths is limited. The aim was to compare the stress repartition on a standard uncemented stem and a shortened uncemented femoral stem with the same design features. Material and methods: This finite element analysis assessed the stress repartition on two femoral components with the same design (uncemented, collared, proximal trapezoidal cross-section, and a tapered quadrangular distal stem) but with two different lengths. The shortened stem was shorter by 40 mm compared to the standard stem. The stress repartition was analysed according to the Von Mises criterion. Results: The stress repartition was similar for the standard and shorter stem without significant difference (p = 0.94). The mean Von Mises stress was 58.1 MPa [0.2; 154.1] for the standard stem and 57.2 MPa [0.03; 160.2] for the short stem. The distal part of the standard stem, which was removed in the short stem, had mean stress of 3.7 MPa [0.2; 7.0]. Conclusion: The finite element analysis found similar stress repartitions between a standard uncemented collared stem and a short, collared stem with the same design. A clinical study assessing the clinical outcomes and the bone remodelling with a collared short stem would be interesting to confirm these first promising results.

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.

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.

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.

A comparative study between zirconia and titanium abutments on the stress distribution in parafunctional loading: A 3D finite element analysis

2020 ◽  
Vol 28 (6) ◽  
pp. 603-613 ◽  
Author(s):  
Efe Can Sivrikaya ◽  
Mehmet Sami Guler ◽  
Muhammed Latif Bekci
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Principal Stresses ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
3D Fea ◽  
Von Mises ◽  
Three Dimensional Finite Element

BACKGROUND: Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. OBJECTIVES: The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). METHODS: Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. RESULTS: In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. CONCLUSIONS: Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.

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