Design of Metacarpophalangeal Single-Piece Joint Prosthesis to Increase Motion in Abduction/Adduction

2019 ◽  
Author(s):  
Nathan Millard ◽  
Raymond K. Yee
Keyword(s):  
Shear Strain ◽  
Strain Energy ◽  
Equivalent Stress ◽  
Distal Portion ◽  
Equivalent Strain ◽  
Cross Sectional ◽  
Finite Element Software ◽  
Single Piece ◽  
Flexion Extension ◽  
Flexion And Extension

Abstract One of the leading causes of disability is rheumatoid arthritis (RA), especially that of the hand, the metacarpophalangeal (MCP) joint being affected the most. Current single piece prostheses are designed to allow for motion in flexion and extension, but little effort is put towards motion in abduction and adduction. The objective of this study is to determine the effects of web (hinge) joint cross-sectional geometry on stress, strain, shear strain, strain energy, and reaction moment magnitude for an MCP joint that is subject to not only flexion and extension but also abduction and adduction. Using finger bone dimensions from the literature, geometry was produced in ANSYS finite element software. The geometry was assigned a hyperelastic material constitutive model, making the analysis nonlinear. The cross-sectional shape of the hinge was controlled by ellipse dimensions, one for thickness and one for width. Motion boundary conditions were applied to the distal portion of the model resulting in bending at the hinge. The study showed that for flexion/extension motion the von Mises (equivalent) stress, shear strain, and equivalent strain are linearly proportional to the thickness but inversely proportional to the width. The reaction moment and strain energy are linearly proportional to the thickness but exponentially proportional to the width. For motion in abduction and adduction the behavior is opposite; the width acting as the thickness does in flexion/extension motion and the thickness acting as the width does in flexion/extension motion. It was also seen that high levels of shear strain develop on the palmer side of the model, indicating that failure has the most potential to occur in that area.

Numerical Simulation of Canned Hot-Extrusion Process of Mo Powder

2011 ◽  
Vol 295-297 ◽  
pp. 1341-1346
Author(s):  
Jian Li ◽  
Jun Zhang
Keyword(s):  
Equivalent Stress ◽  
Hot Extrusion ◽  
Material Model ◽  
Extrusion Process ◽  
Equivalent Strain ◽  
Maximum Temperature ◽  
Entrance Angle ◽  
Finite Element Software ◽  
The Press ◽  
Maximum Equivalent Stress

Aiming at the stress state in the hot-extrusion process of Mo powder, the paper has studied the 3D stress characteristics provided by the hot-extrusion of the canning. The material model is established by the finite element software DEFORM-3D. Via calculating, the load-stroke curve, temperature, relative density, the equivalent stress and the equivalent strain distribution characteristics were obtained. The results show that canned powder after hot-extrusion technology can improve its density greatly. The press load grows fleetly at early, and then slowly grows at the stable stage. Only reach last stage the press load drops quickly of the hot-extrusion. The maximum temperature and maximum equivalent strain appear below the die entrance. The maximum equivalent stress appears in the die entrance. Therefore ,the die entrance angle and the surface geometric parameters of the die have significant effects on the equivalent stress.

New strain energy-based critical plane approach for multiaxial fatigue life prediction

2019 ◽  
Vol 54 (5-6) ◽  
pp. 310-319
Author(s):  
Meng-Fei Hao ◽  
Shun-Peng Zhu ◽  
Ding Liao
Keyword(s):  
Fatigue Life ◽  
Strain Energy ◽  
Equivalent Stress ◽  
Equivalent Strain ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Critical Plane Approach ◽  
Energy Aspect ◽  
Life Predictions

Based on critical plane approach, this article develops a new damage parameter through combing the equivalent strain energy aspect for multiaxial fatigue analysis, which includes no additional fitted parameters and overcomes the deficiency of using only equivalent stress/strain criterion separately under multiaxial loadings. Then, experimental data of GH4169, TC4, Al 7050-T7451 alloys under different loading conditions are applied for model validation and comparison with other four models. Results indicate that the proposed damage parameter yields better multiaxial fatigue life predictions than others.

Study on the Structure of the Flexspline of Harmonic Reducer

2013 ◽  
Vol 385-386 ◽  
pp. 344-347
Author(s):  
Xin Wang ◽  
Xuan Zhou ◽  
Cheng Qun Li
Keyword(s):  
Finite Element ◽  
Optimization Design ◽  
Equivalent Stress ◽  
Equivalent Strain ◽  
Work Process ◽  
Fem Model ◽  
Finite Element Software ◽  
Mechanics Of Materials ◽  
Wave Generator ◽  
Element Theory

According to the flexible gears damage problem during the work process of the harmonic reducer, a FEM model of the flexible and wave generator was established. On the basis of the mechanics of materials and the finite element theory, a large number of numerical simulations by the use of the finite element software were made. The analysis shows that: the dangerous area is between the flexspline tooth rim and cylinder part. On this basis, the equivalent strain and equivalent stress at different transition fillet were discussed by the use of numerical simulation. The results show that: the equivalent strain and equivalent stress are decrease with the increase of the transition fillet. It provides a basis theory of the optimization design of the flexspline.

scholarly journals Analysis Of Light Gauge Steel By Using Fem Subjected To Tension Load

2021 ◽  
Vol 23 (09) ◽  
pp. 590-603
Author(s):  
Dr.A. Paulmakesh ◽  
◽  
Gizachew Markos Makebo ◽  
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Equivalent Stress ◽  
Model Material ◽  
Cross Sectional ◽  
Finite Element Software ◽  
Tension Load ◽  
Steel Angle ◽  
Cold Formed Steel ◽  
Tension Members

The effective sectional area concept was adopted to conduct the analysis of cold-formed Tension members. ANSYS software was utilized to simulate the behavior of cold-formed steel angle under tension load. The paper describes the results from a finite element investigation into the load capacity tension members of single angle sections of 1.5,.1.6,2 3,4 mm and double angles sections of 2mm under plain (without Lipped) and with Lipped conditions subjected to tension. Numerical investigations were carried out using finite element software ANSYS. In order to simulate the experimental behavior using the analytical model, material non-linearity’s and geometric nonlinearity’s were incorporated. The ultimate strength for cross – sectional dimensions with varying eccentricity loads under tension loading conditions was achieved through the ANSYS 15.0 workbench. In the numerical investigation, 180 specimens were modeled on tensioning elements attached to bolts. To find equivalent stress, equivalent elastic strain and total deformation of single and double-angle sections were investigated.

scholarly journals Instability analysis of a filament-wound composite tube subjected to compression/bending

2019 ◽  
Vol 28 ◽  
pp. 096369351987741
Author(s):  
Gyula Szabó ◽  
Károly Váradi
Keyword(s):  
Failure Modes ◽  
Slenderness Ratio ◽  
Equivalent Stress ◽  
Bending Test ◽  
Test Machine ◽  
Fe Model ◽  
Rubber Tube ◽  
Nonlinear Buckling ◽  
Cross Sectional ◽  
Composite Tube

The aim of this study is to investigate the global buckling of a relatively long composite cord–rubber tube subjected to axial compression and its cross-sectional instability due to bending by a macromechanical nonlinear finite element (FE) model (nonlinear buckling analysis). Composite reinforcement layers are modelled as transversely isotropic ones, while elastomer liners are described by a hyperelastic material model that assumes incompressibility. Force–displacement, equivalent strain, equivalent stress results along with oblateness and curvature results for the complete process have been presented. It is justified that bending leads to ovalization of the cross section and results in a loss of the load-carrying capacity of the tube. Strain states in reinforcement layers have been presented, which imply that the probable failure modes of the reinforcement layers are both delamination and yarn-matrix debonding. There is a significant increase in strains due to cross-sectional instability, which proves that the effect of cross-sectional instability on material behaviour of the tube is crucial. A parametric analysis has been performed to investigate the effect of the member slenderness ratio on cross-sectional instability of the composite tube. It shows that Brazier force is inversely proportional to the slenderness ratio. It further shows that higher oblateness parameters occur in case of a lower slenderness ratio and that cross-sectional instability takes place at a lower dimensionless displacement in case of a lower slenderness ratio. FE results have been validated by a compression/bending test experiment conducted on a tensile test machine.

scholarly journals Joint-Specific Play Controller for Upper Extremity Therapy: Feasibility Study in Children With Wrist Impairment

2016 ◽  
Vol 96 (11) ◽  
pp. 1773-1781
Author(s):  
Bethany J. Wilcox ◽  
Megan M. Wilkins ◽  
Benjamin Basseches ◽  
Joel B. Schwartz ◽  
Karen Kerman ◽  
...  
Keyword(s):  
Upper Extremity ◽  
Computer Games ◽  
Average Frequency ◽  
Cross Sectional Study ◽  
Wrist Flexion ◽  
Motor Impairments ◽  
Cross Sectional ◽  
Play Activity ◽  
Play Session ◽  
Flexion And Extension

Abstract Background Challenges with any therapeutic program for children include the level of the child's engagement or adherence. Capitalizing on one of the primary learning avenues of children, play, the approach described in this article is to develop therapeutic toy and game controllers that require specific and repetitive joint movements to trigger toy/game activation. Objective The goal of this study was to evaluate a specially designed wrist flexion and extension play controller in a cohort of children with upper extremity motor impairments (UEMIs). The aim was to understand the relationship among controller play activity, measures of wrist and forearm range of motion (ROM) and spasticity, and ratings of fun and difficulty. Design This was a cross-sectional study of 21 children (12 male, 9 female; 4–12 years of age) with UEMIs. Methods All children participated in a structured in-clinic play session during which measurements of spasticity and ROM were collected. The children were fitted with the controller and played with 2 toys and 2 computer games for 5 minutes each. Wrist flexion and extension motion during play was recorded and analyzed. In addition, children rated the fun and difficulty of play. Results Flexion and extension goal movements were repeatedly achieved by children during the play session at an average frequency of 0.27 Hz. At this frequency, 15 minutes of play per day would result in approximately 1,700 targeted joint motions per week. Play activity was associated with ROM measures, specifically supination, but toy perception ratings of enjoyment and difficulty were not correlated with clinical measures. Limitations The reported results may not be representative of children with more severe UEMIs. Conclusions These outcomes indicate that the therapeutic controllers elicited repetitive goal movements and were adaptable, enjoyable, and challenging for children of varying ages and UEMIs.

Research on NX-Based Progressive Die Design

2012 ◽  
Vol 602-604 ◽  
pp. 1818-1821
Author(s):  
Jun Liu ◽  
Cong Dong Ji
Keyword(s):  
Design Method ◽  
Equivalent Stress ◽  
Equivalent Strain ◽  
Die Design ◽  
Support Design ◽  
Stress Resilience ◽  
Progressive Die ◽  
Key Technology ◽  
Product Manufacturing ◽  
Progressive Die Design

Progressive die has been widely used in product manufacturing field. This paper proposed a NX-based computer server support design method. The equivalent stress, resilience, equivalent strain, attenuation, and forming were analyzed in detail. The key technology of confirming blank dimension and stock layout of server support were explicated clearly.

Elasto-plastic and creep behaviour of axially loaded, shouldered tubes

1980 ◽  
Vol 15 (1) ◽  
pp. 21-29 ◽  
Author(s):  
R J Dawson ◽  
H Fessler ◽  
T H Hyde ◽  
J J Webster
Keyword(s):  
Finite Element ◽  
Creep Behaviour ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Equivalent Strain ◽  
Uniaxial Tensile ◽  
Plastic Strain Increment ◽  
Axially Loaded ◽  
Initial Strains ◽  
Creep Strains

This paper compares the finite element predictions of elasto-plastic and creep behaviour with experimental data for axially loaded, shouldered tube models. Four shouldered tube models were made of a lead alloy and tested at 61°C, using strain gauges to measure the elasto-plastic and creep strains in the plain tube and fillet regions of the models. Instantaneous stress-strain and creep data were obtained from strain-gauged, uniaxial tensile specimens. The finite element solutions are based on the incremental Prandtl-Reuss equations. The elasto-plastic iterative solutions use a ‘negative gradient’ from the calculated point to the equivalent stress-equivalent strain curve to get the next estimate of the plastic strain increment. A time incremental method is used to obtain the creep solutions. Tests with the mean tube stress below, at and above the yield stress showed very good agreement between prediction and measurement of initial strains in the fillets. Differences between predictions and measurements of creep strains are attributable to cast-to-cast variations.

Change of the critical thickness in the preferred orientation of TiN films

1995 ◽  
Vol 10 (3) ◽  
pp. 634-639 ◽  
Author(s):  
U.C. Oh ◽  
Jung Ho Je ◽  
Jeong Y. Lee
Keyword(s):  
Strain Energy ◽  
Unit Volume ◽  
Critical Thickness ◽  
Preferred Orientation ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Working Pressure ◽  
Cross Sectional ◽  
Tin Films ◽  
Tin Thin Films

Recently it was observed through cross-sectional TEM that the preferred orientation of the TiN thin film was changed from (200) to (111) with thickness. In this study, the process of the change in the preferred orientation was studied near the critical thickness by x-ray diffraction, and the value of the critical thickness could be estimated. The change of the critical thickness was also investigated with the strain energy per unit volume. The strain energy could be changed by controlling the energy of the bombarding particle, i.e., by adjusting the rf power, the working pressure, and the substrate bias in sputtering. The critical thickness was decreased monotonically in all cases as the energy of the bombarding particle or the strain energy per unit volume was increased. These results surely show the dependence of the change of the preferred orientation on the strain energy in the TiN thin films.

Toe Flexor Strength, Flexibility and Function and Flexor Hallucis Longus Tendon Morphology in Dancers and Non-Dancers

2015 ◽  
Vol 30 (3) ◽  
pp. 152-156 ◽  
Author(s):  
KM Rowley ◽  
Danielle N Jarvis ◽  
Toshiyuki Kurihara ◽  
Yu-Jen Chang ◽  
Abbigail L Fietzer ◽  
...  
Keyword(s):  
Flexor Hallucis Longus ◽  
Cross Sectional ◽  
Joint Range Of Motion ◽  
High Prevalence ◽  
Balance Ability ◽  
Tendon Thickness ◽  
Toe Flexor Strength ◽  
And Function ◽  
Joint Range ◽  
Flexion And Extension

Tendinopathy of the flexor hallucis longus (FHL), colloquially referred to as “dancer’s tendinitis,” is a common condition in dancers and attributed to high demand on this muscle in positions of extreme ankle plantarflexion and metatarsophalangeal (MTP) flexion and extension. Despite such a high prevalence, there has been little research into preventative or nonsurgical interventions. As a means to identify potential targets for prevention and intervention, this study aimed to characterize toe flexors in dancers by measuring strength, flexibility, function, and FHL tendon morphology. Dancers (n=25) were compared to non-dancers (n=25) in toe flexor isometric strength, first MTP joint range of motion, foot longitudinal arch flexibility, balance ability, endurance during modified heel raises without use of the toes, and FHL tendon thickness, cross-sectional area, and peak spatial frequency. Significant differences were found in functional first MTP joint extension (dancers 101.95º, non-dancers 91.15º, p<0.001), balance ability during single-leg stance on the toes (dancers 11.43 s, non-dancers 5.90 s, p=0.013), and during modified heel raises (dancers 22.20 reps, non-dancers 28.80 reps, p=0.001). Findings indicate that dancers rely on toe flexors more than non-dancers to complete balance and heel raise tasks. Efficacy of using this modified heel raise task with the toes off the edge of a block as a means to train larger plantarflexors and as a nonsurgical intervention should be studied in the future. Improving interventions for FHL tendinopathy will be impactful for dancers, in whom this condition is highly prevalent.

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