Multi-layered bird beaks: a finite-element approach towards the role of keratin in stress dissipation

Bird beaks are layered structures, which contain a bony core and an outer keratin layer. The elastic moduli of this bone and keratin were obtained in a previous study. However, the mechanical role and interaction of both materials in stress dissipation during seed crushing remain unknown. In this paper, a multi-layered finite-element (FE) model of the Java finch's upper beak ( Padda oryzivora ) is established. Validation measurements are conducted using in vivo bite forces and by comparing the displacements with those obtained by digital speckle pattern interferometry. Next, the Young modulus of bone and keratin in this FE model was optimized in order to obtain the smallest peak von Mises stress in the upper beak. To do so, we created a surrogate model, which also allows us to study the impact of changing material properties of both tissues on the peak stresses. The theoretically best values for both moduli in the Java finch are retrieved and correspond well with previous experimentally obtained values, suggesting that material properties are tuned to the mechanical demands imposed during seed crushing.

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A Novel Rat Model of Orthodontic Tooth Movement Using Temporary Skeletal Anchorage Devices: 3D Finite Element Analysis andIn VivoValidation

International Journal of Dentistry ◽

10.1155/2014/917535 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Neelambar Kaipatur ◽

Yuchin Wu ◽

Samer Adeeb ◽

Thomas Stevenson ◽

Paul Major ◽

...

Keyword(s):

Finite Element ◽

Alveolar Bone ◽

Tooth Movement ◽

Orthodontic Tooth Movement ◽

Von Mises Stress ◽

Fe Model ◽

Sprague Dawley ◽

Element Analysis ◽

Von Mises ◽

The Right

The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built usingμCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. Forin vivovalidation of the FE model, Sprague-Dawley rats (n=25) were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs.

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Identification of Surgical Plan for Syndesmotic Fixation Procedure Based on Finite Element Method

Applied Sciences ◽

10.3390/app10124349 ◽

2020 ◽

Vol 10 (12) ◽

pp. 4349 ◽

Cited By ~ 1

Author(s):

Tae Sik Goh ◽

Beop-Yong Lim ◽

Jung Sub Lee ◽

Chi-Seung Lee

Keyword(s):

Finite Element ◽

Simulation Method ◽

Fe Analysis ◽

Von Mises Stress ◽

Fe Model ◽

Syndesmotic Screw ◽

Surgical Options ◽

Biomechanical Parameters ◽

Von Mises ◽

Two Parameters

Syndesmosis injuries account for approximately 20% of ankle fractures that require surgery. Although multiple surgical options are available, all of them are based on metal screws. Serious complications that arise when applying metal screws include screw loosening or breakage. To prevent such complications, we applied a simulation method using a finite element (FE) analysis. We created a 3D FE model of an ankle joint and conducted an FE analysis focusing on syndesmosis in terms of the level, material, and diameter of the syndesmotic screw and the number of penetrated cortical bones. The magnitude and direction of the force applied to the tibia in the midstance state were considered for simulating the model. The maximum von-Mises stress and syndesmosis widening were analyzed in terms of different biomechanical parameters. We identified the characteristics of the most biomechanically stable syndesmotic screw and its fixation point on the basis of the two parameters. We demonstrated that the ideal syndesmotic screw fixation should be fixed at a level 20 to 25 mm above the ankle using a 4.5 mm titanium screw.

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Development of a Finite Element Head Model for the Study of Impact Head Injury

BioMed Research International ◽

10.1155/2014/408278 ◽

2014 ◽

Vol 2014 ◽

pp. 1-14 ◽

Cited By ~ 21

Author(s):

Bin Yang ◽

Kwong-Ming Tse ◽

Ning Chen ◽

Long-Bin Tan ◽

Qing-Qian Zheng ◽

...

Keyword(s):

Finite Element ◽

Brain Injuries ◽

Current Knowledge ◽

Human Head ◽

Von Mises Stress ◽

Head Model ◽

Fe Model ◽

Prediction And Prevention ◽

Von Mises ◽

The Brain

This study is aimed at developing a high quality, validated finite element (FE) human head model for traumatic brain injuries (TBI) prediction and prevention during vehicle collisions. The geometry of the FE model was based on computed tomography (CT) and magnetic resonance imaging (MRI) scans of a volunteer close to the anthropometry of a 50th percentile male. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue. The cerebrospinal fluid (CSF) was simulated explicitly as a hydrostatic fluid by using a surface-based fluid modeling method. The model was validated in the loading condition observed in frontal impact vehicle collision. These validations include the intracranial pressure (ICP), brain motion, impact force and intracranial acceleration response, maximum von Mises stress in the brain, and maximum principal stress in the skull. Overall results obtained in the validation indicated improved biofidelity relative to previous FE models, and the change in the maximum von Mises in the brain is mainly caused by the improvement of the CSF simulation. The model may be used for improving the current injury criteria of the brain and anthropometric test devices.

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Effects of Revision Rod Position on Spinal Construct Stability in Lumbar Revision Surgery: A Finite Element Study

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.799727 ◽

2022 ◽

Vol 9 ◽

Author(s):

Quan-Chang Tan ◽

Jin-Feng Huang ◽

Hao Bai ◽

Zi-Xuan Liu ◽

Xin-Yi Huang ◽

...

Keyword(s):

Finite Element ◽

Revision Surgery ◽

Spinal Instrumentation ◽

Axial Rotation ◽

Von Mises Stress ◽

Fe Model ◽

Interspinous Ligament ◽

Moment Load ◽

Von Mises ◽

Changing Tendency

Revision surgery (RS) is a necessary surgical intervention in clinical practice to treat spinal instrumentation–related symptomatic complications. Three constructs with different configurations have been applied in RS. One distinguishing characteristic of these configurations is that the revision rods connecting previous segments and revision segments are placed alongside, outside, or inside the previous rods at the level of facetectomy. Whether the position of the revision rod could generate mechanical disparities in revision constructs is unknown. The objective of this study was to assess the influence of the revision rod position on the construct after RS. A validated spinal finite element (FE) model was developed to simulate RS after previous instrumented fusion using a modified dual-rod construct (DRCm), satellite-rod construct (SRC), and cortical bone trajectory construct (CBTC). Thereafter, maximum von Mises stress (VMS) on the annulus fibrosus and cages and the ligament force of the interspinous ligament, supraspinous ligament, and ligamentum flavum under a pure moment load and a follower load in six directions were applied to assess the influence of the revision rod position on the revision construct. An approximately identical overall reducing tendency of VMS was observed among the three constructs. The changing tendency of the maximum VMS on the cages placed at L4-L5 was nearly equal among the three constructs. However, the changing tendency of the maximum VMS on the cage placed at L2-L3 was notable, especially in the CBTC under right bending and left axial rotation. The overall changing tendency of the ligament force in the DRCm, SRC, and CBTC was also approximately equal, while the ligament force of the CBTC was found to be significantly greater than that of the DRCm and SRC at L1-L2. The results indicated that the stiffness associated with the CBTC might be lower than that associated with the DRCm and SRC in RS. The results of the present study indicated that the DRCm, SRC, and CBTC could provide sufficient stabilization in RS. The CBTC was a less rigid construct. Rather than the revision rod position, the method of constructing spinal instrumentation played a role in influencing the biomechanics of revision.

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FINITE ELEMENT ANALYSIS OF THE HUMAN HEAD UNDER SIDE CAR CRASH IMPACTS AT DIFFERENT SPEEDS

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519414400028 ◽

2014 ◽

Vol 14 (06) ◽

pp. 1440002 ◽

Cited By ~ 3

Author(s):

XINGQIAO DENG ◽

SHOU AN CHEN ◽

R. PRABHU ◽

YUANYUAN JIANG ◽

Y. MAO ◽

...

Keyword(s):

Finite Element ◽

Brain Injuries ◽

Head Injuries ◽

Human Head ◽

Side Impact ◽

Von Mises Stress ◽

Head Model ◽

Car Crash ◽

Von Mises ◽

The Impact

Mechanical response of the human head under a side car crash impact is crucial for modeling traumatic brain injuries (TBI) or concussions. The current advances in computational methods and the finite element models of the human head provide a significant opportunity for biomechanical study of brain injuries; however, limited experimental data is available for delineating the injury relationship between the head injury criteria (HIC) and the tensile pressure or von Mises stress. In this research, we assess human head injuries in a side impact car crash using finite element (FE) simulations that quantify the tensile pressures and maximum strain profiles. In doing so, five FE analyses for the human head have been carried out to investigate the correlations between the HIC measured in the dummy model at different moving deformable barrier (MDB) velocities increasing from 10 mph to 30 mph in 5 mph increments and the pressure and von Mises stress of the skull, the skin, the cerebral spinal fluid (CSF) and the brain. The computational simulation results for the tensile pressures and von Mises stresses correlated well with the HIC15 and peak accelerations. Also a second-order polynomial seemed to fit the stress levels to the impact speeds and as such the presented method for using FE human head analysis could be used for reconstruction of head impacts in different side car crash conditions; furthermore, the head model would provide a tool for investigation of the cause and mechanisms of head injuries once the type and locations of injuries are quantified.

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DEVELOPMENTS, MECHANICAL PROPERTY MEASUREMENTS AND STRENGTH EVALUATIONS OF THE WRIST BRACES FOR THE WRIST FRACTURE PATIENTS

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519419400219 ◽

2019 ◽

Vol 19 (02) ◽

pp. 1940021

Author(s):

CHUNG-DE CHEN ◽

CHING-HSIANG CHEN ◽

CHENG-LI LIN ◽

CHIEN-KUNG LIN ◽

CHI-TSANG WANG ◽

...

Keyword(s):

Finite Element ◽

Impact Analysis ◽

Element Model ◽

Tensile Tests ◽

Wrist Fracture ◽

Von Mises Stress ◽

3D Scanner ◽

Surface Anatomy ◽

Von Mises ◽

The Impact

In this paper, the wrist braces for the wrist fracture patients are developed. Geometry of the patient’s wrist surface anatomy was digitalized and recorded by an optical 3D scanner. An expert software was developed to generate the brace model, on which several holes are distributed to increase the air permeability. Finally, the brace is fabricated by commercial FDM 3D printer. For ensuring the strength of the wrist brace, the tensile test and impact test were conducted to measure the elastic modulus, yielding strength and fracture strength. A finite element model was established to investigate the stresses and deformations when the wrist brace is subjected to a static load. The mechanical properties measured in the tensile tests are as input parameters in the model. The static analysis showed that, for four considered movements of the wrist, the maximum von-Mises stress is less than the yielding strength. An impact analysis was also conducted to simulate brace impacted by a moving rigid ball with a mass of 0.3768[Formula: see text]kg. The results showed that the deformation at the impact point remains in the elastic range when the impact speed is 3[Formula: see text]m/s. The finite element calculations give us rules to design the number of holes and the thickness of the brace.

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Crash Injury Analysis of Knee Joint Considering Pedestrian Safety

Journal of Biomedical Physics and Engineering ◽

10.31661/jbpe.v0i0.424 ◽

2016 ◽

Author(s):

M Asgari ◽

Sh S Keyvanian

Keyword(s):

Finite Element ◽

Knee Joint ◽

Soft Tissues ◽

Human Anatomy ◽

Von Mises Stress ◽

Physical Parameters ◽

Fe Model ◽

Impact Biomechanics ◽

Pedestrian Accidents ◽

The Impact

Background: Lower extremity injuries are frequently observed in car-to-pedestrian accidents and due to the bumper height of most cars, knee joint is one of the most damaged body parts in car-to-pedestrian collisions.Objective: The aim of this paper is first to provide an accurate Finite Element model of the knee joint and second to investigate lower limb impact biomechanics in car-to-pedestrian accidents and to predict the effect of parameters such as collision speed and height due to the car speed and bumper height on knee joint injuries, especially in soft tissues such as ligaments, cartilages and menisci.Methods: A 3D finite element (FE) model of human body knee joint is developed based on human anatomy. The model consists of femur, tibia, menisci, articular cartilages and ligaments. Material properties of bones and soft tissues were assumed to be elastic, homogenous and isotropic.Results: FE model is used to perform injury reconstructions and predict the damages by using physical parameters such as Von-Mises stress and equivalent elastic strain of tissues.Conclusion: The results of simulations first show that the most vulnerable part of the knee is MCL ligament and second the effect of speed and height of the impact on knee joint. In the critical member, MCL, the damage increased in higher speeds but as an exception, smaller damages took place in menisci due to the increased distance of two bones in the higher speed.

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Different fixation pattern for thoracolumbar fracture of ankylosing spondylitis: A finite element analysis

PLoS ONE ◽

10.1371/journal.pone.0250009 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0250009

Author(s):

Tianyu Zhang ◽

Yanhua Wang ◽

Peixun Zhang ◽

Feng Xue ◽

Dianying Zhang ◽

...

Keyword(s):

Finite Element ◽

Ankylosing Spondylitis ◽

Internal Fixation ◽

Thoracolumbar Fracture ◽

Von Mises Stress ◽

Fe Model ◽

Pull Force ◽

Kyphosis Correction ◽

Four Levels ◽

Von Mises

The objective of this study is to establish an ankylosing spondylitis (AS) thoracolumbar fracture finite element (FE) model and provide a proper posterior fixation choice from the biomechanical perspective. The ankylosing spondylitis T9-L5 FE model was built and the range of motion (ROM) was compared to previous studies. The L1 transverse fracture was simulated and was separately fixed by five different patterns. The pull force and yielding force of the screws, the von Mises stress of the internal fixation, and the displacement of fracture site were analyzed to evaluate the proper fixation pattern for thoracolumbar fracture of AS. ROM of AS model was obviously restricted comparing to the normal vertebral experimental data. All the fixation patterns can stabilize the fracture. At least four levels of fixation can reduce the von Mises stress of the internal fixation. Four levels fixation has a higher pull force than the six levels fixation. Skipped level fixation did not reduce the stress, pull force and yielding force. The kyphosis correction did not change the biomechanical load. At least 4 levels fixation was needed for AS thoracolumbar fracture. The cemented screws should be chosen in 4 levels fixation to increase the holding of the screws. The skipped fixation has no advantage. The kyphosis correction can be chosen after weighing the pros and cons.

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To Evaluate the Influence of Implant Length on Stress Distribution of Osseointegrated Implant: A Three-Dimensional Finite Element Analysis: An In Vitro Study

Dental Journal of Advance Studies ◽

10.1055/s-0038-1677646 ◽

2018 ◽

Vol 6 (02/03) ◽

pp. 097-105

Author(s):

Neha Jindal ◽

Manjit Kumar ◽

Shailesh Jain ◽

Navjot Kaur ◽

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Stress Distribution ◽

Biomechanical Analysis ◽

Von Mises Stress ◽

Element Analysis ◽

Von Mises ◽

The Impact ◽

Implant Length ◽

Nonsignificant Decrease

AbstractFinite element analysis is a technique for obtaining a solution to a complex mechanical problem by dividing the problem domain into a collection of much smaller and simpler domains (elements) in which the field variables can be interpolated with the use of shape functions. An overall approximated solution to the original problem is determined based on variational principles. Finite element analysis can provide a nondestructive system for quantifying stresses generated at the various interfaces of similar or dissimilar material. The finite element method also allows the study of the internal state of stress of components as well as stress patterns in two or more dissimilar materials adjacent to each other without affecting their independent behavior. This method is therefore ideally suitable for the biomechanical analysis of orthopedic, cardiovascular, and dental structures. In this study, implants of different length were numerically analyzed using bone-implant models developed from computed tomography-generated images of the mandible with osseointegrated implants. The impact of various lengths on stress distribution was examined using implants with a length of 8, 10, and 13 mm in mandibular first molar region under axial load of 100 N and buccolingual load of 50 N. All materials were assumed to be linearly elastic and isotropic. The Statistical Package for the Social Sciences software package was used for statistical analysis. Maximum von Mises stresses were located around the implant neck. It was demonstrated that there was statistically nonsignificant decrease in von Mises stress as the implant length increased. Within the limitations of this study, there was statistically nonsignificant decrease in von Mises stress as the implant length increased.

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Biomechanical Behavior of Bioactive Material in Dental Implant: A Three-Dimensional Finite Element Analysis

The Scientific World JOURNAL ◽

10.1155/2020/2363298 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Vathsala Patil ◽

Nithesh Naik ◽

Srikanth Gadicherla ◽

Komal Smriti ◽

Adithya Raju ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Graphene Oxide ◽

Titanium Implant ◽

Von Mises Stress ◽

Implant Design ◽

Element Analysis ◽

Von Mises ◽

Implant System ◽

The Impact

Dental implants are widely accepted for the rehabilitation of missing teeth due to their aesthetic compliance, functional ability, and great survival rate. The various components in implant design like thread design, thread angle, pitch, and material used for manufacturing play a critical role in its success. Understanding these influencing factors and implementing them properly in implant design can reduce cases of potential implant failure. Recently, finite element analysis (FEA) is being widely used in the field of health sciences to solve problems in designing medical devices. It provides valid and accurate assessment in the clinical and in vitro analysis. Hence, this study was conducted to evaluate the impact of thread design of the implant and 3 different bioactive materials, titanium alloy, graphene, and reduced graphene oxide (rGO) on stress, strain, and deformation in the implant system using FEA. In this study, the FEA model of the bones and the tissues are modeled as homogeneous, isotropic, and linearly elastic material with a titanium implant system with an assumption of it 100% osseointegrated into the bone. The titanium was functionalized with graphene and graphene oxide. A modeling software tool Catia® and Ansys Workbench® is used to perform the analysis and evaluate the von Mises stress distribution, strain, and deformation at the implant and implant-cortical bone interface. The results showed that the titanium implant with a surface coating of graphene oxide exhibited better mechanical behavior than graphene, with mean von Mises stress of 39.64 MPa in pitch 1, 23.65 MPa in pitch 2, and 37.23 MPa in pitch 3. It also revealed that functionalizing the titanium implant will help in reducing the stress at the implant system. Overall, the study emphasizes the use of FEA analysis methods in solving various biomechanical issues about medical and dental devices, which can further open up for invivo study and their practical uses.

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