scholarly journals Are CT-Based Finite Element Model Predictions of Femoral Bone Strengthening Clinically Useful?

2018 ◽  
Vol 16 (3) ◽  
pp. 216-223 ◽  
Author(s):  
Marco Viceconti ◽  
Muhammad Qasim ◽  
Pinaki Bhattacharya ◽  
Xinshan Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Femoral Bone ◽  
Model Predictions

scholarly journals Correction to: Are CT-Based Finite Element Model Predictions of Femoral Bone Strength Clinically Useful?

2018 ◽  
Vol 17 (6) ◽  
pp. 580-580
Author(s):  
Marco Viceconti ◽  
Muhammad Qasim ◽  
Pinaki Bhattacharya ◽  
Xinshan Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bone Strength ◽  
Element Model ◽  
Femoral Bone ◽  
Model Predictions

Rigid-Plastic Impact of Single Angular Particles

2021 ◽  
Author(s):  
Sandeep Dhar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Orientation Dependence ◽  
Particle Orientation ◽  
Rigid Plastic ◽  
Plastic Model ◽  
Model Predictions ◽  
Good Agreement ◽  
Angular Particles

The trajectory of an angular particle as it cuts a ductile target is, in general, complicated because of its dependence not only on particle shape, but also on particle orientation at the initial instant of impact. This orientation dependence has also made experimental measurement of impact parameters of single angular particles very difficult, resulting in a relatively small amount of available experimental data in the literature. The current work is focused on obtaining measurements of particle kinematics for comparison to rigid plastic model developed by Papini and Spelt. Fundamental mechanisms of material removal are identified, and measurements of rebound parameters and corresponding crater dimensions of single hardened steel particles launched against flat aluminium alloy targets are presented. Also a 2-D finite element model is developed and a dynamic analysis is performed to predict the erosion mechanism. Overall, a good agreement was found among the experimental results, rigid-plastic model predictions and finite element model predictions.

Assessment of a finite element model for plate shearing

2002 ◽  
Vol 216 (4) ◽  
pp. 519-529 ◽  
Author(s):  
J P Domblesky ◽  
L Zhao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Plane Strain ◽  
Element Model ◽  
Experimental Results ◽  
Process Conditions ◽  
Initiation And Propagation ◽  
Model Predictions ◽  
Edge Wear ◽  
Strain Model

A study was conducted to assess the robustness of a plane strain finite element model that was developed to simulate plate shearing using the Cockroft-Latham fracture criterion and element deletion. Model predictions for blade gap, ductility and edge wear were compared with published experimental results. Results showed that the model was able to simulate initiation and propagation of fracture lines at the punch and die corners and the resultant break angle along the edge was found to be close to values observed in practice. Simulated edge geometry and microhardness were found to be in reasonable agreement with published experimental results for the steel plate considered although the model was unable to simulate double cutting at 0.8 per cent clearance. Results also suggest that edge hardness is independent of the starting ductility in the plate and that increasing the edge radii does not effectively simulate edge wear. Based on the results obtained, it may be concluded that the plane strain model is able to simulate plate shearing with sufficient accuracy in the range of normal process conditions.

A Finite Element Model of Cell-Matrix Interactions to Study the Differential Effect of Scaffold Composition on Chondrogenic Response to Mechanical Stimulation

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Taly P. Appelman ◽  
Joseph Mizrahi ◽  
Dror Seliktar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Loading ◽  
Mechanical Stimulation ◽  
Element Model ◽  
Encapsulated Cells ◽  
Cell Matrix ◽  
Matrix Interactions ◽  
Model Predictions ◽  
Cell Matrix Interactions

Mechanically induced cell deformations have been shown to influence chondrocyte response in 3D culture. However, the relationship between the mechanical stimulation and cell response is not yet fully understood. In this study a finite element model was developed to investigate cell-matrix interactions under unconfined compression conditions, using a tissue engineered encapsulating hydrogel seeded with chondrocytes. Model predictions of stress and strain distributions within the cell and on the cell boundary were shown to exhibit space-dependent responses that varied with scaffold mechanical properties, the presence of a pericellular matrix (PCM), and the cell size. The simulations predicted that when the cells were initially encapsulated into the hydrogel scaffolds, the cell size hardly affected the magnitude of the stresses and strains that were reaching the encapsulated cells. However, with the inclusion of a PCM layer, larger cells experienced enhanced stresses and strains resulting from the mechanical stimulation. It was also noted that the PCM had a stress shielding effect on the cells in that the peak stresses experienced within the cells during loading were significantly reduced. On the other hand, the PCM caused the stresses at the cell-matrix interface to increase. Based on the model predictions, the PCM modified the spatial stress distribution within and around the encapsulated cells by redirecting the maximum stresses from the periphery of the cells to the cell nucleus. In a tissue engineered cartilage exposed to mechanical loading, the formation of a neo-PCM by encapsulated chondrocytes appears to protect them from initially excessive mechanical loading. Predictive models can thus shed important insight into how chondrocytes remodel their local environment in order to redistribute mechanical signals in tissue engineered constructs.

scholarly journals IWSHM 2017: Application of guided wave methods to quantitatively assess healing in osseointegrated prostheses

2018 ◽  
Vol 17 (6) ◽  
pp. 1377-1392 ◽  
Author(s):  
Wentao Wang ◽  
Jerome P Lynch
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Longitudinal Wave ◽  
Bone Healing ◽  
Guided Waves ◽  
Element Model ◽  
Wave Mode ◽  
Guided Wave ◽  
Care Providers ◽  
Femoral Bone

Osseointegrated prosthesis is essentially a prosthetic fixture surgically implanted into the bone that extends out of the limb so that an artificial limb can be attached. While osseointegrated prostheses can dramatically improve the quality of life of amputees, there remains a lack of quantitative evidence of the osseointegration process that occurs at the bone–prosthesis surface after surgery. This study advances a sensing strategy that employs piezoelectric elements mounted to the percutaneous end of the prosthesis to generate guided waves that propagate along the length of the prosthesis fixture. The properties of the guided waves exhibit sensitivity to both the degree of bone healing that occurs at the prosthesis surface and the movement of the prosthesis due to loss of osseointegration. Use of the prosthesis as a wave guide offers care providers a quantitative approach to determining when an osseointegrated prosthesis can be loaded and tracks the integrity of osseointegration over the lifespan of the amputee. The study validates the proposed guided wave strategy using a prosthesis model consisting of a solid titanium rod implanted in an adult femoral bone. First, a high-fidelity finite element model is created to study changes in guided waves as a result of bone healing. A laboratory model is also adopted using a synthetic femoral bone identical to that modeled in the finite element model. The energy of the first longitudinal wave mode introduced at the percutaneous end of the prosthesis provides a repeatable metric for accurate assessment of both osseointegration and prosthesis pullout from the bone. The results of this study reveal that the energy of the longitudinal wave mode decreases by nearly half during the osseointegration healing process. In addition, the wave energy is also found to increase as the osseointegrated fixture loosens and is withdrawn from the bone.

Flow and heat transfer in CVD reactors: Comparison of Raman temperature measurements and finite element model predictions

1990 ◽  
Vol 100 (3) ◽  
pp. 577-599 ◽  
Author(s):  
Dimitrios I. Fotiadis ◽  
Martin Boekholt ◽  
Klavs F. Jensen ◽  
Wolfgang Richter
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Temperature Measurements ◽  
Flow And Heat Transfer ◽  
Model Predictions

Experimental Validation of a Finite Element Model of an Osteoporotic Human Femoral Bone Using Strain Gauge Measurement

2014 ◽  
Vol 658 ◽  
pp. 513-519
Author(s):  
Ioana Alexandra Takacs ◽  
Mircea Cristian Dudescu ◽  
Mihail Hărdău ◽  
Adrian Ioan Botean
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Gauge ◽  
Computer Aided Design ◽  
Experimental Validation ◽  
Element Model ◽  
Femoral Bone ◽  
Vitro Analysis ◽  
Gauge Measurement

The complications of fractures caused by osteoporosis have a mortality rate of 15-20 % in elderly people, leading to severe physical disability and long term home care [1]. Although currently, the technology that allows us to prevent osteoporosis and fractures caused by this disease exists, the statistics are concerning and can be considered basis for further research regarding this pathology of the bone tissue. This paper aims to address this issue form an engineering perspective by achieving experimental validation of a finite element model of an osteoporotic human femoral bone using strain gauge measurement for an in vitro analysis. A Computer Aided Design (CAD) model based on a CT of a human femoral bone was then used in a numerical analysis. The material constants used are taken from the literature and have been validated experimentally by strain gauge technique.

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