Analysis and Evaluating of Flexible Ankle Foot Orthosis for Drop Foot Deformity

2020 ◽  
Vol 398 ◽  
pp. 41-47 ◽  
Author(s):  
Fahad Mohanad Kadhim ◽  
Marfa Salah Hayal
Keyword(s):  
Composite Material ◽  
Reaction Force ◽  
Good Control ◽  
Trunk Muscles ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Experimental Part ◽  
Sound Side ◽  
The Difference ◽  
Von Mises

This work involved two major parts: the first Part is the experimental part included manufacturing ankle foot orthotics, measure the (the reaction force of the ground, pressure distribution) for both normal (healthy) and sound side (intake) legs in two case, the first measurement when the patient walking without orthosis while the second test when the patient dressed up the flexible (AFO). The pressure generated between leg and calf part is measured by F-Socket devise. The experimental part also consist test the mechanical properties of a suggestion composite material. The second Part is the (FEM) finite element analysis for numerical simulation part during which the stresses are calculated using ANSYS 14.5 software. Experimental work was done on a case study suffering from low level spinal cord trauma he has good control of the trunk muscles but the muscle weakness and nerve damage for right leg. The patient with age, weight of 30years, 75kg, respectively. The Results show the parameters of test for both legs (left and right) in two cases. The results show that the data of the gait cycle in the case of the patient wearing the brace is more acceptable and we notice improvement in the performance of walking steps and reduce the difference between the infected leg and natural and this indicates the good evaluation of this orthosis. Max pressure obtained is 1.53*10^5MPa from F .Socket at calf region .Max stress Calculated at Posterior ankle joint because it is flexible Position The equivalent Von-Mises stress and the safety factor for fatigue of the composite material gave good results this led to the longer life design.

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.

Evaluation and Analysis of Different Types of Prosthetic Knee Joint Used by above Knee Amputee

2020 ◽  
Vol 398 ◽  
pp. 34-40 ◽  
Author(s):  
Fahad Mohanad Kadhim ◽  
Jumaa Salman Chiad ◽  
Maryam Abdul Salam Enad
Keyword(s):  
Gait Cycle ◽  
Reaction Force ◽  
Maximum Velocity ◽  
Knee Joints ◽  
Von Mises Stress ◽  
Prosthetic Knee ◽  
Prosthetic Limb ◽  
Left And Right ◽  
The Difference ◽  
Von Mises

Four prosthetic knee joints (polycentric knee weight activating-4bar and friction, extension assist controlled),(single axis knee weight activating and friction, internal extension assist controlled), (single axis knee weight activating-4bar and hydraulically, controlled) and (polycentric knee geometric locking-6bar, hydraulically controlled) for a trans-femoral patient were tested. The tests were conducted to find the maximum velocity as well as discussing the most comfortable prosthetic forthe patient and walking stability for these prosthetic knees by examining the gait cycle and measuring the ground reaction force (GRF), using force a plate device. Also, the interface pressure was measured between socket and stump muscles by using F-socket device to get the stress distribution during walking with a prosthetic knee. Results manifested that the polycentric knee geometric locking - 6bar, hydraulically controlled is the best because of the good homogenous distribution of GRF between the healthy and prosthetic limb, during which the difference between both the healthy and prosthetic limb is with the least value (4%).And, K4 gives the minimum value of differences in contact pressure between the left and right limb with a value of (24%), it alsoimparts the maximum symmetry between the left and right limb according to the gait cycle parameters.The best results of the interface pressures and kinovea velocity are achieved whenK4 is used with (132.4KPa, 0.71m/s), respectively. Finally, the polycentric knee geometric locking - 6bar, hydraulically controlled is the best according to the ANSYS results during which it yields the minimum values of Von-Mises stress with 14.24MPa and a maximum factor of safety of 3.11.

FE Analysis of the Effect of Material Gradient on the Performance of a Functionally Graded Endodontic Prefabricated Parallel Post

2015 ◽  
Vol 752-753 ◽  
pp. 382-386 ◽  
Author(s):  
Wasim M.K. Helal ◽  
Dong Yan Shi ◽  
Zhi Kai Wang
Keyword(s):  
Shear Stress ◽  
Volume Fraction ◽  
Fe Analysis ◽  
Functionally Graded ◽  
Von Mises Stress ◽  
Sigmoid Function ◽  
Current Investigation ◽  
Element Analysis ◽  
The Difference ◽  
Von Mises

A study of the effect of material gradient on the performance of a functionally graded endodontic prefabricated parallel post (FGEPPP) is the main goal of the current study. Elastic modulus (E) of FGEPPP is considered to vary continuously from lower to upper surfaces. This variation is performed according the volume fraction. Based on a modified sigmoid function, the volume fraction will be defined in the present work. The primary goal of the current investigation is to analyze the difference between the performance of a homogeneous endodontic prefabricated parallel post (EPPP) and a FGEPPP through finite element analysis (FEA). In the current investigation, von Mises stress, and shear stress in FGEPPP case with a modified sigmoid function and in homogeneous EPPP case are carried out. After that, the effect of material gradient on the performance of an EPPP made of FGM was carried out through FEA in the current investigation. The simulation cases shown that, the maximum values of von Mises stress, and shear stress increase when increasing the value of “D”, and decrease when increasing the value of “w”.

scholarly journals The Mechanical Behaviors of Various Dental Implant Materials under Fatigue

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Fatma Bayata ◽  
Cengiz Yildiz
Keyword(s):  
Surface Properties ◽  
Dental Implant ◽  
Mechanical Performance ◽  
Bone Structure ◽  
Von Mises Stress ◽  
Implant Design ◽  
Element Analysis ◽  
The Difference ◽  
Von Mises ◽  
Cp Ti

The selection of materials has a considerable role on long-term stability of implants. The materials having high resistance to fatigue are required for dental implant applications since these implants are subjected to cyclic loads during chewing. This study evaluates the performance of different types of materials (AISI 316L stainless steel, alumina and its porous state, CoCr alloys, yttrium-stabilized zirconia (YSZ), zirconia-toughened alumina (ZTA), and cp Ti with the nanotubular TiO2 surface) by finite element analysis (FEA) under real cyclic biting loads and researches the optimum material for implant applications. For the analysis, the implant design generated by our group was utilized. The mechanical behavior and the life of the implant under biting loads were estimated based on the material and surface properties. According to the condition based on ISO 14801, the FEA results showed that the equivalent von Mises stress values were in the range of 226.95 MPa and 239.05 MPa. The penetration analysis was also performed, and the calculated penetration of the models onto the bone structure ranged between 0.0037389 mm and 0.013626 mm. L-605 CoCr alloy-assigned implant model showed the least penetration, while cp Ti with the nanotubular TiO2 surface led to the most one. However, the difference was about 0.01 mm, and it may not be evaluated as a distinct difference. As the final numerical evaluation item, the fatigue life was executed, and the results were achieved in the range of 4 × 105 and 1 × 109 cycles. These results indicated that different materials showed good performance for each evaluation component, but considering the overall mechanical performance and the treatment process (implant adsorption) by means of surface properties, cp Ti with the nanotubular TiO2 surface material was evaluated as the suitable one, and it may also be implied that it displayed enough performance in the designed dental implant model.

scholarly journals Wind Mill Shaft Optimization Based on layer Orientation Angles using Composite Materials

2020 ◽  
Vol 9 (8) ◽  
pp. 677-684
Keyword(s):  
Composite Material ◽  
Material Selection ◽  
Fibre Orientation ◽  
Von Mises Stress ◽  
Optimization Analysis ◽  
Element Analysis ◽  
Transmission Shaft ◽  
Layer Orientation ◽  
Von Mises ◽  
Strength Improvement

This paper presents an application of Finite Element Analysis (FEA) for strength improvement of wind mill shaft. Also provides fundamental knowledge of transmission shaft analysis using composite material. The existing shaft is modelled using CATIA and analyzed using ANSYS 16.0. The results for stresses generated are shear stress 68.298MPa, von-mises stress 119.2MPa and deformation is 3.3905mm. First optimization is done based on fibre orientation angles of composite material. Further alternate material selection is done through study and optimization analysis is done for the same. Carbon epoxy-UD selected as material and gives final stresses as 22.974MPa and deformation is 1.255mm. The torsion deflections were obtained experimentally. The results of experimental study and FEA results are found same as infinite life.

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

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 Biomechanical assessment of different fixation methods in mandibular high sagittal oblique osteotomy using a three-dimensional finite element analysis model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles Savoldelli ◽  
Elodie Ehrmann ◽  
Yannick Tillier
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Analysis Model ◽  
Element Analysis ◽  
Fixation Methods ◽  
Oblique Osteotomy ◽  
Von Mises

AbstractWith modern-day technical advances, high sagittal oblique osteotomy (HSOO) of the mandible was recently described as an alternative to bilateral sagittal split osteotomy for the correction of mandibular skeletal deformities. However, neither in vitro nor numerical biomechanical assessments have evaluated the performance of fixation methods in HSOO. The aim of this study was to compare the biomechanical characteristics and stress distribution in bone and osteosynthesis fixations when using different designs and placing configurations, in order to determine a favourable plating method. We established two finite element models of HSOO with advancement (T1) and set-back (T2) movements of the mandible. Six different configurations of fixation of the ramus, progressively loaded by a constant force, were assessed for each model. The von Mises stress distribution in fixations and in bone, and bony segment displacement, were analysed. The lowest mechanical stresses and minimal gradient of displacement between the proximal and distal bony segments were detected in the combined one-third anterior- and posterior-positioned double mini-plate T1 and T2 models. This suggests that the appropriate method to correct mandibular deformities in HSOO surgery is with use of double mini-plates positioned in the anterior one-third and posterior one-third between the bony segments of the ramus.

scholarly journals Effect of Ring Material and Diameter on Orthopedic Implant Stability: External Fixation in Femur Bone

2018 ◽  
Vol 7 (4.26) ◽  
pp. 190 ◽  
Author(s):  
Nur Fatin Izzati Ibrahim ◽  
Ruslizam Daud ◽  
Muhammad Khairul Ali Hassan ◽  
Noor Ali Hassan ◽  
Noor Alia Md Zain ◽  
...  
Keyword(s):  
External Fixation ◽  
Von Mises Stress ◽  
Axial Stiffness ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Ring Diameter ◽  
The Stability ◽  
Von Mises ◽  
Fixation Frame ◽  
Ring Material

Axial stiffness is the most important factor in stability. It is known that any changes in the diameter of any components of the frame will either increase or decrease the axial stiffness of the fixation. The model of implant and bone will be variety as the variables changes. Current studies states that ring stability are one of the most important factors in ensuring fractured bones to have a successful re-union. In circular external fixation, the stability of the pin-bone interaction is influenced by the stability of the fixation frame where the major component is the rings. The objective is to study the finite element analysis (FEA) of the external fixator assembled in human diaphysis under compression force with different materials of the exoskeleton which are stainless steel, titanium alloy, magnesium alloy and carbon fiber. The results obtained show the mechanical strength of each material where it will be used to compare the value of von-Mises stress, stiffness and total deformation to acquire the best suitable ring diameter and material. Based on the result, as the diameter of the ring increases, the stiffness of the ring will be decreased. 

scholarly journals The Effect of Nanoparticles in Single Lap Joints Studied by Numerical Analyses

2020 ◽  
Vol 5 (10) ◽  
pp. 1288-1293
Author(s):  
Panagiotis J. Charitidis
Keyword(s):  
Finite Element ◽  
Failure Load ◽  
Tensile Loading ◽  
Lap Joints ◽  
Von Mises Stress ◽  
Adhesive Material ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Epoxy Adhesives ◽  
Von Mises

The present study concerns with the finite element investigation of balanced aluminium single lap joints subjected to tensile loading. Epoxy adhesives were used for bonding having different nanoparticles rate in the epoxy resin (0.5, 1.0, 1.5 and to 2 wt. %, respectively). Two-dimensional (2D) finite element analysis has been employed to determine the peeling stress, von Mises stress, and the shear strain distribution across the midplane of the joints. The results mainly prove that the nanoparticles rate in the adhesive material directly affects the joint tensile strength. Nanocomposite adhesives present a higher failure load than that of neat adhesives. Furthermore, nanocomposite adhesive with 0.5 wt. % of nanoparticles generated strengths (shear and peeling strengths) more than neat adhesives, after which decreased by further addition of the nanoparticles.

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