scholarly journals Stress distribution in the bonobo (Pan paniscus) trapeziometacarpal joint during grasping

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12068
Author(s):  
Timo van Leeuwen ◽  
G. Harry van Lenthe ◽  
Evie E. Vereecke ◽  
Marco T. Schneider
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Pan Paniscus ◽  
Distribution Patterns ◽  
Stress Distributions ◽  
Element Analysis ◽  
High Agreement ◽  
Form Function ◽  
Individual Variations ◽  
Stress Patterns

The primate thumb plays a central role in grasping and the basal trapeziometacarpal (TMC) joint is critical to its function. The TMC joint morphology varies across primates, yet little is known about form-function interaction within in the TMC joint. The purpose of this study was to investigate how stress distributions within the joint differ between five grasping types commonly employed by bonobos (Pan paniscus). Five cadaveric bonobo forearms were CT scanned in five standardized positions of the hand as a basis for the generation of parametric finite element models to compare grasps. We have developed a finite element analysis (FEA) approach to investigate stress distribution patterns in the TMC joint associated with each grasp type. We hypothesized that the simulated stress distributions for each position would correspond with the patterns expected from a saddle-shaped joint. However, we also expected differences in stress patterns arising from instraspecific variations in morphology. The models showed a high agreement between simulated and expected stress patterns for each of the five grasps (86% of successful simulations), while partially (52%) and fully (14%) diverging patterns were also encountered. We identified individual variations of key morphological features in the bonobo TMC joint that account for the diverging stress patterns and emphasized the effect of interindividual morphological variation on joint functioning. This study gives unprecedented insight in the form-function interactions in the TMC joint of the bonobo and provides an innovative FEA approach to modelling intra-articular stress distributions, a valuable tool for the study of the primate thumb biomechanics.

Finite Element Analysis of Poor Distal Contact of the Femoral Component of a Cementless Hip Endoprosthesis

1993 ◽  
Vol 207 (4) ◽  
pp. 255-261 ◽  
Author(s):  
M Taylor ◽  
E W Abel
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Hip Endoprosthesis ◽  
Applied Loading ◽  
Femoral Geometry ◽  
Contact Models

The difficulty of achieving good distal contact between a cementless hip endoprosthesis and the femur is well established. This finite element study investigates the effect on the stress distribution within the femur due to varying lengths of distal gap. Three-dimensional anatomical models of two different sized femurs were generated, based upon computer tomograph scans of two cadaveric specimens. A further six models were derived from each original model, with distal gaps varying from 10 to 60 mm in length. The resulting stress distributions within these were compared to the uniform contact models. The extent to which femoral geometry was an influencing factor on the stress distribution within the bone was also studied. Lack of distal contact with the prosthesis was found not to affect the proximal stress distribution within the femur, for distal gap lengths of up to 60 mm. In the region of no distal contact, the stress within the femur was at normal physiological levels associated with the applied loading and boundary conditions. The femoral geometry was found to have little influence on the stress distribution within the cortical bone. Although localized variations were noted, both femurs exhibited the same general stress distribution pattern.

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.

scholarly journals A Comparative Analysis of Standardised Threads for Use in Implants for Direct Skeletal Attachment of Limb Prosthesis: A Finite Element Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Piotr Prochor ◽  
Eugeniusz Sajewicz
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Analysis ◽  
Stress Distribution ◽  
Additional Stress ◽  
Element Analysis ◽  
Proposed Modification ◽  
Implant Loading ◽  
Stress Patterns ◽  
Limb Prosthesis

The aim of the research was to determine the optimal thread’s shape to be used in implants for direct skeletal attachment of limb prosthesis. In addition, by testing appropriate parameters’ modification of the suitable thread, an attempt was made to maximise its effectiveness. The analyses included three thread types described in the ISO standards: shallow, symmetrical, and asymmetrical. The obtained results suggest that shallow thread ensures the lowest equivalent and directional stress peaks generated in the bone as well as favourable stress patterns and profiles during implant loading in relation to symmetrical and asymmetrical threads. Moreover, shallow thread ensured the generation of single equivalent and directional stress peaks, while symmetrical and asymmetrical threads provided additional stress peak for equivalent as well as for each of directional peaks. Subsequently, optimisation of the shallow thread’s shape was conducted by changing two relevant thread’s parameters (flank angle and rounding arc) which influence the generated stress distribution. The highest reduction of stress peaks was obtained while reducing the rounding arc by 0.2 mm. Therefore, it can be stated that the proposed modification of the HA thread can lead to obtaining a higher biomechanical effectiveness of implants for direct skeletal attachment of limb prosthesis.

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.

A NOVEL METHOD FOR THE DESIGN OF PROSTHESES BASED ON THERMOELASTIC STRESS ANALYSIS AND FINITE ELEMENT ANALYSIS

2014 ◽  
Vol 14 (05) ◽  
pp. 1450064
Author(s):  
FERDINANDO CANNELLA ◽  
ALBERTO GARINEI ◽  
MARIAPAOLA D'IMPERIO ◽  
GIANLUCA ROSSI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Low Cost ◽  
Thermoelastic Stress ◽  
Fe Model ◽  
Element Analysis ◽  
The People ◽  
Teak Wood ◽  
Stress Patterns

This work is about a prosthesis destined for the people of Senegal and the victims of mines that have been spread throughout countries involved in war. The purpose of this study is to design a new, low-cost prosthesis using the materials produced in Senegal: teak wood and iron (AISI 304). In order to optimize the design of the new prosthesis, a methodology was developed to evaluate stress patterns for different configurations. A commercial CAD and ANSYS Workbench were used to define prosthesis geometry and to perform Finite Element Analysis. Load and constraints were defined according to Regulation ISO10328-2006, and stress distribution was estimated using the FE model. Fatigue due to the cycling load was also taken into account. The two materials currently used in western countries, titanium and steel (AISI 1020), were compared to iron and teak in order to determine the prosthesis' lifespan based on the differences in structural behaviors. An experimental, non-contact measurement technique based on the Thermoelastic principle is proposed here to validate the FE model. This technique permits the evaluation of superficial stress patterns on the prosthesis subjected to a cyclic load. A loading rig was built to test the prosthesis, and experimental and FEM results were compared to allow qualitative mechanical assessment of the new prosthesis. The finding of this work was that the prosthesis can indeed be built using autochthonous materials such as teak and iron. Moreover, the methodology proposed can be used for the performance prediction and design of new prostheses using materials that are typically expensive or difficult to test (such as wood), allowing for optimization of the geometry based on stress distribution, an increase in reliability and a decrease in costs.

scholarly journals Retention System and Splinting on Morse Taper Implants in the Posterior Maxilla by 3D Finite Element Analysis

2018 ◽  
Vol 29 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Cleidiel Aparecido Araujo Lemos ◽  
Fellippo Ramos Verri ◽  
Joel Ferreira Santiago Júnior ◽  
Daniel Augusto de Faria Almeida ◽  
Victor Eduardo de Souza Batista ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Bone Tissue ◽  
Stress Distributions ◽  
Element Analysis ◽  
3D Finite Element ◽  
3D Finite Element Analysis ◽  
Posterior Maxilla ◽  
Oblique Loading

Abstract The purpose of this study was to evaluate different retention systems (cement- or screw-retained) and crown designs (non-splinted or splinted) of fixed implant-supported restorations, in terms of stress distributions in implants/components and bone tissue, by 3-dimensional (3D) finite element analysis. Four 3D models were simulated with the InVesalius, Rhinoceros 3D, and SolidWorks programs. Models were made of type III bone from the posterior maxillary area. Models included three 4.0-mm-diameter Morse taper (MT) implants with different lengths, which supported metal-ceramic crowns. Models were processed by the Femap and NeiNastran programs, using an axial force of 400 N and oblique force of 200 N. Results were visualized as the von Mises stress and maximum principal stress (σmax). Under axial loading, there was no difference in the distribution of stress in implants/components between retention systems and splinted crowns; however, in oblique loading, cemented prostheses showed better stress distribution than screwed prostheses, whereas splinted crowns tended to reduce stress in the implant of the first molar. In the bone tissue cemented prostheses showed better stress distribution in bone tissue than screwed prostheses under axial and oblique loading. The splinted design only had an effect in the screwed prosthesis, with no influence in the cemented prosthesis. Cemented prostheses on MT implants showed more favorable stress distributions in implants/components and bone tissue. Splinting was favorable for stress distribution only for screwed prostheses under oblique loading.

scholarly journals Finite Element Analysis of the Endodontically-treated Maxillary Premolars restored with Composite Resin along with Glass Fiber Insertion in Various Positions

2015 ◽  
Vol 16 (4) ◽  
pp. 284-290 ◽  
Author(s):  
Elmira Jafari Navimipour ◽  
Fatemeh Sadat Mirhashemi
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Glass Fiber ◽  
Composite Resin ◽  
Fem Analysis ◽  
Distribution Patterns ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Maxillary Premolars ◽  
Von Mises

ABSTRACT Aim This study evaluated the effect of three methods of glass fiber insertion on stress distribution pattern and cusp movement of the root-filled maxillary premolars using finite element method (FEM) analysis. Materials and methods A three-dimensional (3D) FEM model of a sound upper premolar tooth and four models of root-filled upper premolars with mesiocclusodistal (MOD) cavities were molded and restored with: (1) Composite resin only (NF); (2) Composite resin along with a ribbon of glass fiber placed in the occlusal third (OF); (3) Composite resin along with a ribbon of glass fiber placed circumferentially in the cervical third (CF), and (4) Composite resin along with occlusal and circumferential fibers (OCF). A static vertical load was applied to calculate the stress distributions. Structural analysis program by Solidworks were used for FEM analysis. Von-Mises stress values and cusp movements induced by occlusal loading were evaluated. Results Maximum Von-Mises stress of enamel occurred in sound tooth, followed by NF, CF, OF and OCF. Maximum Von- Mises stress of dentin occurred in sound tooth, followed by OF, OCF, CF and NF. Stress distribution patterns of OF and OCF were similar. Maximum overall stress values were concentrated in NF. Although stress distribution patterns of NF and CF were found as similar, CF showed lower stress values. Palatal cusp movement was more than buccal cusp in all of the models. Conclusion The results of our study indicated that while the circumferential fiber had little effect on overall stress concentration, it provided a more favorable stress distribution pattern in cervical region. The occlusal fiber reduced the average stress in the entire structure but did not reduce cuspal movement. Clinical significance Incorporating glass fiber in composite restorations may alter the stress state within the structure depending on fiber position. How to cite this article Navimipour EJ, Firouzmandi M, Mirhashemi FS. Finite Element Analysis of the Endodonticallytreated Maxillary Premolars restored with Composite Resin along with Glass Fiber Insertion in Various Positions. J Contemp Dent Pract 2015;16(4):284-290.

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