Numerical and Experimental Analysis of Articular Chondrocyte Deformation: Calibration of a Multiscale Finite Element Model

2007 ◽  
Author(s):  
Scott L. Bevill ◽  
Paul L. Briant ◽  
Thomas P. Andriacchi
Keyword(s):  
Finite Element ◽  
Load Transfer ◽  
Numerical Models ◽  
Experimental Studies ◽  
Element Model ◽  
Cartilage Explants ◽  
Fe Model ◽  
Articular Chondrocyte ◽  
Superficial Zone

Mechanical loading of chondrocytes in isolation [1] and of articular cartilage in culture [2] has been reported to be a potent regulator of chondrocyte metabolism. Experimental studies have related tissue-level and cell-level strains in mechanically loaded cartilage explants [3], but cannot be readily extended to address more physiologic loading cases. Numerical models, which might address this need, have primarily been axisymmetric [4, 5] or two-dimensional [6] and have idealized chondrocyte geometry. Given the complexity of the mechanism of the load transfer between the tissue and cell, however, there remains a lack of information regarding the in vivo level of cell stresses and strains. Thus, the purpose of this study was to develop a multiscale experimental/numerical approach to calibrate a three-dimensional finite element (FE) model of a chondrocyte based on experimentally derived chondrocyte morphology and deformation data. The method was than applied to determine the modulus of a chondrocyte located in the superficial zone.

A Biomechanical Model of Lumbar Spine

2000 ◽  
Author(s):  
Subramanya Uppala ◽  
Robert X. Gao ◽  
Scott Cowan ◽  
K. Francis Lee
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Biomechanical Model ◽  
Element Model ◽  
Fe Model ◽  
Flexion Extension ◽  
Cortical Shell ◽  
Three Dimensional Finite Element

Abstract The strength and stability of the lumbar spine are determined not only by the bone and muscles, but also by the visco-elastic structures and the interplay between the different components of the spine, such as ligaments, capsules, annulus fibrosis, and articular cartilage. In this paper we present a non-linear three-dimensional Finite Element model of the lumbar spine. Specifically, a three-dimensional FE model of the L4-5 one-motion segment/2 vertebrae was developed. The cortical shell and the cancellous bone of the vertebral body were modeled as 3D isoparametric eight-nodal elements. Finite element models of spinal injuries with fixation devices are also developed. The deformations across the different sections of the spine are observed under the application of axial compression, flexion/extension, and lateral bending. The developed FE models provided input to both the fixture design and experimental studies.

Automotive Glass Exciter Technology for Acoustic Application

2014 ◽  
Author(s):  
Babak Ebrahimi ◽  
Amir Khajepour ◽  
Todd Deaville
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Experimental Studies ◽  
Element Model ◽  
Fe Model ◽  
Component Level ◽  
Modeling And Analysis ◽  
Electric Actuator ◽  
Conventional Systems ◽  
Fine Tune

This paper discusses the modeling and analysis of a novel audio subwoofer system for automotive applications using the automobile windshield glass. The use of a piezo-electric actuator coupled with a mechanical amplifier linked to a large glass panel provides a highly efficient method of producing sound. The proposed subwoofer system has the advantage over existing conventional systems of not only reducing the weight of the automobile, but also a significant power savings resulting in an increase of expected fuel economy. Among various design challenges, the glass-sealing design is of huge importance, as it affects the system dynamic response and so the output sound characteristics. The main goal in this manuscript is to evaluate different glass-sealing design configurations by providing a comprehensive Finite Element model of the system. To do so, a comprehensive, yet simplified FE model is developed, and experimental studies are performed in the component level to fine-tune and verify the model. Harmonic response of the system for each sealing configuration design is obtained in the frequency range of 0–200 Hz, and the results are compared and discussed. The finite element model is also beneficial in preliminary design of other components as well as the exciter placement, and predicting the performance of the overall system.

scholarly journals A musculoskeletal finite element model of rat knee joint for evaluating cartilage biomechanics during gait

2021 ◽  
Author(s):  
Gustavo A. Orozco ◽  
Kalle Karjalainen ◽  
Eng Kuan Moo ◽  
Lauri Stenroth ◽  
Petri Tanska ◽  
...  
Keyword(s):  
Finite Element ◽  
Animal Models ◽  
Knee Joint ◽  
Gait Cycle ◽  
Numerical Models ◽  
Small Animal ◽  
Element Model ◽  
Lateral Compartment ◽  
Fe Model ◽  
Joint Injury

Abnormal loading of the knee due to injuries or obesity is thought to contribute to the development of osteoarthritis (OA). Small animal models have been used for studying OA progression mechanisms. However, numerical models to study cartilage responses under dynamic loading in preclinical animal models have not been developed. Here we present a musculoskeletal finite element (FE) model of a rat knee joint to evaluate cartilage biomechanical responses during a gait cycle. The rat knee joint geometries were obtained from a 3-D MRI dataset and the boundary conditions regarding loading in the joint were extracted from a musculoskeletal model of the rat hindlimb. The fibril-reinforced poroelastic (FRPE) properties of the rat cartilage were derived from data of mechanical indentation tests. Our numerical results showed the relevance of simulating anatomical and locomotion characteristics in the rat knee joint for estimating tissue responses such as contact pressures, stresses, strains, and fluid pressures. We found that the contact pressure and maximum principal strain were virtually constant in the medial compartment whereas they showed the highest values at the beginning of the gait cycle in the lateral compartment. Furthermore, we found that the maximum principal stress increased during the stance phase of gait, with the greatest values at midstance. We anticipate that our approach serves as a first step towards investigating the effects of gait abnormalities on the adaptation and degeneration of rat knee joint tissues and could be used to evaluate biomechanically-driven mechanisms of the progression of OA as a consequence of joint injury or obesity.

NONLINEAR FINITE ELEMENT ANALYSIS OF FRP STRENGTHENED RC BEAMS

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Prabin Pathak ◽  
Y. X. Zhang
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Experimental Studies ◽  
Material Model ◽  
Element Model ◽  
Steel Reinforcement ◽  
Elastic Model ◽  
Fe Model ◽  
Rc Beams ◽  
Element Analysis

A simple, accurate and efficient finite element model is developed in ANSYS for numerical modelling of the nonlinear structural behavior of FRP strengthened RC beams under static loading in this paper. Geometric nonlinearity and material non-linear properties of concrete and steel rebar are accounted for this model. Concrete and steel reinforcement are modelled using Solid 65 element and Link 180 element, and FRP and adhesive are modelled using Shell 181element and Solid 45 element. Concrete is modelled using Nitereka and Neal’s model for compression, and isotropic and linear elastic model before cracking with strength gradually reducing to zero after cracking for tension. For steel reinforcement, the elastic perfectly plastic material model is used. FRPs are assumed to be linearly elastic until rupture and epoxy is assumed to be linearly elastic. The new FE model is validated by comparing the computed results with those obtained from experimental studies.

Damping Matrix Identification by Finite Element Model Updating Using Frequency Response Data

2017 ◽  
Vol 17 (01) ◽  
pp. 1750004 ◽  
Author(s):  
S. Pradhan ◽  
S. V. Modak
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Frequency Response ◽  
Model Updating ◽  
Experimental Studies ◽  
Element Model ◽  
Fe Model ◽  
Damping Matrix ◽  
Steel Cast ◽  
Identification Techniques

Accurate modeling of damping is essential for prediction of vibration response of a structure. This paper presents a study of damping matrix identification method using experimental data. The identification is done by performing finite element (FE) model updating using normal frequency response functions (FRFs). The paper addresses some key issues like data incompleteness and computation of the normal FRFs for carrying out the model updating using experimental data. The effect of various levels of damping in structures on the performance of the identification techniques is also investigated. Experimental studies on three beam structures made up of mild steel, cast iron and acrylic are presented to demonstrate the effectiveness of the identification techniques for different levels of damping.

scholarly journals Nonlinear Finite Element Modelling of Railway Turnout System considering Bearer/Sleeper-Ballast Interaction

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
James Sae Siew ◽  
Olivia Mirza ◽  
Sakdirat Kaewunruen
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Load Transfer ◽  
Element Model ◽  
Operational Reliability ◽  
Fe Model ◽  
Rail Network ◽  
Numerical Studies ◽  
Frequent Monitoring ◽  
Great Consideration

Rail turnouts are built to enable flexibility in the rail network as they allow for vehicles to switch between various tracks, therefore maximizing the utilisation of existing rail infrastructure. In general, railway turnouts are a safety-critical and expensive feature to a rail system as they suffer aggressive operational loads, in comparison to a plain rail track, and thus require frequent monitoring and maintenance. In practice, great consideration is given to the dynamic interaction between the turnouts components as a failed component may have adverse effects on the performance of neighbouring components. This paper presents a nonlinear 3D finite element (FE) model, taking into account the nonlinearities of materials, in order to evaluate the interaction and behaviour of turnout components. Using ABAQUS, the finite element model was developed to simulate standard concrete bearers with 60 kg/m rail and with a tangential turnout radius of 250 m. The turnout structure is supported by a ballast layer, which is represented by a nonlinearly deformable tensionless solid. The numerical studies firstly demonstrate the importance of load transfer mechanisms in the failure modes of the turnout components. The outcome will lead to a better design and maintenance of railway turnouts, improving public safety and operational reliability.

Finite Element Modeling and Experimental Studies of Stack-Type Piezoelectric Energy Harvester

2017 ◽  
Vol 09 (06) ◽  
pp. 1750084 ◽  
Author(s):  
L. V. Duong ◽  
M. T. Pham ◽  
V. A. Chebanenko ◽  
A. N. Solovyev ◽  
Chuong V. Nguyen
Keyword(s):  
Finite Element ◽  
Output Voltage ◽  
Energy Harvester ◽  
Numerical Models ◽  
Experimental Studies ◽  
Fe Model ◽  
Resistive Load ◽  
Piezoelectric Energy ◽  
Load Rate ◽  
1D Model

In this paper, closed-form coupled electromechanical one-dimensional (1D) model and finite element (FE) model for stack-type piezoelectric energy harvester (PEH) and delivery to a resistive load available in the literature were proposed. We obtained the values of some parameters of 1D model and set the boundaries of its applicability based on the comparison of the resonance frequency and output voltage between the FE model and 1D model. The numerical modeling results of the full-scale experiment with low-frequency pulse excitation of the stack-type PEH for the energy storage device are described. PEH is a multilayer axisymmetric piezoceramic package. The dependence between the output voltage and the current load rate under the harmonic and non-stationary mechanical action of the PEH is studied. The experimental results-to-numerical calculation correlation has shown their good coincidence, which allows using the analyzed numerical models to optimize the PEH design at the given external action frequency and the active resistance value of the external electric circuit. Besides, it found that the frequency dependence of the output voltage of the stack-type PEH is of a complex nature depending both on the compressive pulse loading level and the piezoelectric modulus value of the PEH sensitive element, and on the electrical load resistance.

Validate Mandible Finite Element Model under Removable Partial Denture (RPD) with In Vivo Pressure Measurement

2014 ◽  
Vol 553 ◽  
pp. 322-326 ◽  
Author(s):  
Hanako Suenaga ◽  
Jun Ning Chen ◽  
Wei Li ◽  
Keiichiro Yamaguchi ◽  
Keiichi Sasaki ◽  
...  
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Patient Specific ◽  
Fe Model ◽  
Removable Partial Denture ◽  
Partial Denture ◽  
Element Simulation ◽  
Clinical Measurements

This study aims to analyze the functional contact pressure induced by Removable Partial Denture (RPD) by using a 3D finite element (FE) model constructed based on patient specific CT scans. This model was validated against the in vivo test results. The outcomes demonstrate that the finite element simulation has the capability of quantifying localized stress distribution in a complicated denture-mucosa contact problem, with a reasonable matching to clinical measurements of occlusal force and pressure distribution. The methodology is of considerable clinical implication to improve the long term outcomes of the denture treatment.

Fatigue Assessment of a Slender Footbridge Based on an Updated Finite Element Model

2018 ◽  
Vol 774 ◽  
pp. 589-594
Author(s):  
J. Pérez-Aracil ◽  
A.M. Hernandez-Díaz ◽  
J.F. Jiménez-Alonso ◽  
F.J. Puerta-Lopez
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fatigue Damage ◽  
Model Updating ◽  
Numerical Models ◽  
Vertical Direction ◽  
Element Model ◽  
Modal Parameters ◽  
Fe Model ◽  
Fatigue Assessment

Finite element model updating is a well-known technique to better characterize the real behaviour of civil engineering structures. The updated numerical model can be used to perform a more accurate structural assessment. Herein, its effectiveness is validated through the fatigue assessment of a lively footbridge considering two different numerical models: (i) a preliminary finite element (FE) model and (ii) an updated version of the preliminary model based on the modal parameters of the footbridge identified experimentally. For this purpose, the Malecon footbridge (Murcia, Spain) has been considered. This footbridge, a cable-stayed structure, is prone to vibrate in vertical direction under continuous walking pedestrian flows so fatigue damage might be expected on its supporting cables. A detailed FE model of the footbridge has been performed and subsequently updated based on the experimental modal parameters of the structure. The behaviour of the pedestrian flows was characterized by field observations. Finally, a comparison is performed between the fatigue damage of some cables of the footbridge considering the two mentioned FE models. The safe life method was used to assess such damage. As result, a maximum relative difference around 52 % was obtained between the two numerical models.

scholarly journals NUMERICAL INVESTIGATION OF THE BEARING CAPACITY OF TRANSVERSELY PRESTRESSED CONCRETE DECK SLABS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Sana Amir ◽  
Cor van der Veen ◽  
Joost Walraven ◽  
Ane de Boer ◽  
Joost C. Walraven
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Numerical Models ◽  
Experimental Studies ◽  
Shear Capacity ◽  
Punching Shear ◽  
Scale Model ◽  
Fe Model ◽  
Deck Slabs ◽  
Concrete Deck

The paper investigates the effect of various geometrical and material parameters on the bearing (punching shear) capacity of transversely prestressed concrete deck slabs by numerical methods. Experiments on a 1:2 scale model of such a bridge were carried out in the laboratory and a 3D nonlinear finite element (FE) model was developed in the finite element analysis software package TNO DIANA (2012) to study the structural behavior in punching shear. A comparison of the experimental and numerical ultimate loads show that the non-linear FE models can predict the load carrying capacity quite accurately with a standard deviation of 0.1 and the coefficient of variation of only 10%. The effect of varying the transverse prestressing level, the presence and size of the ducts, size of the loading plate and the concrete class is also described as part of the parametric study. It was observed that sufficient saving in cost could be made if calibrated numerical models are employed to investigate existing structures rather than doing expensive experimental studies.

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