Experimental Validation of a Finite Element Model of the Proximal Femur Using Digital Image Correlation and a Composite Bone Model

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
A. S. Dickinson ◽  
A. C. Taylor ◽  
H. Ozturk ◽  
M. Browne
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Finite Element Model ◽  
Digital Image ◽  
Proximal Femur ◽  
Element Model ◽  
Image Correlation ◽  
Generation Process ◽  
Full Field ◽  
Biomechanical Models

Computational biomechanical models are useful tools for supporting orthopedic implant design and surgical decision making, but because they are a simplification of the clinical scenario they must be carefully validated to ensure that they are still representative. The goal of this study was to assess the validity of the generation process of a structural finite element model of the proximal femur employing the digital image correlation (DIC) strain measurement technique. A finite element analysis model of the proximal femur subjected to gait loading was generated from a CT scan of an analog composite femur, and its predicted mechanical behavior was compared with an experimental model. Whereas previous studies have employed strain gauging to obtain discreet point data for validation, in this study DIC was used for full field quantified comparison of the predicted and experimentally measured strains. The strain predicted by the computational model was in good agreement with experimental measurements, with R2 correlation values from 0.83 to 0.92 between the simulation and the tests. The sensitivity and repeatability of the strain measurements were comparable to or better than values reported in the literature for other DIC tests on tissue specimens. The experimental-model correlation was in the same range as values obtained from strain gauging, but the DIC technique produced more detailed, full field data and is potentially easier to use. As such, the findings supported the validity of the model generation process, giving greater confidence in the model’s predictions, and digital image correlation was demonstrated as a useful tool for the validation of biomechanical models.

Finite element model updating from full-field vibration measurement using digital image correlation

2011 ◽  
Vol 330 (8) ◽  
pp. 1599-1620 ◽  
Author(s):  
Weizhuo Wang ◽  
John E. Mottershead ◽  
Alexander Ihle ◽  
Thorsten Siebert ◽  
Hans Reinhard Schubach
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Finite Element Model ◽  
Digital Image ◽  
Model Updating ◽  
Element Model ◽  
Image Correlation ◽  
Vibration Measurement ◽  
Finite Element Model Updating ◽  
Full Field

A study of loading rate effect fracture behavior of concrete based on digital image correlation and finite-element method

2020 ◽  
pp. 030932472094862
Author(s):  
Xudong Chen ◽  
Chen Chen ◽  
Xiyuan Cheng ◽  
Chaoguo Wu ◽  
Zhenxiang Shi ◽  
...  
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Finite Element Model ◽  
Digital Image ◽  
Fracture Process ◽  
Loading Rate ◽  
Element Model ◽  
Rate Effect ◽  
Image Correlation ◽  
Extended Finite Element

To study the rate effect on the fracture properties of concrete, 700 mm × 150 mm × 100 mm specimens with a 60-mm notch were used for three-point bending test at the loading rate of 0.0005, 0.005, 0.05, and 0.5 mm/s, respectively. In the test, digital image correlation was used for monitoring the fracture process. The result shows that the fracture stress, unstable fracture toughness, and fracture energy have rate sensitivity. The numerical simulation was performed by extended finite-element model. The model calibration had a very good agreement with the experimental result under different loading rate. Meanwhile, fracture process zone length calculated by digital image correlation is similar to the result obtained by the extended finite-element model under different loading rate.

Use of Digital Image Correlation to Track Strain Evolution in Compressed Masonry Piers

2015 ◽  
Vol 732 ◽  
pp. 337-340
Author(s):  
Jakub Antoš ◽  
Václav Nežerka ◽  
Pavel Tesárek
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Localization ◽  
Material Model ◽  
Element Model ◽  
Image Correlation ◽  
Full Field ◽  
Constitutive Material Model ◽  
The Cost ◽  
Constitutive Material

In order to develop a constitutive material model and to verify its consistency when implemented in a computational code, it is necessary to understand the material and to carry out a comprehensive experimental analysis. This can be a challenging task in the case of composite materials and structures, such as masonry, when using conventional measurements. Strain gauges and allow recording strains at a limited number of discrete points and do not provide sufficient amount of data, thus increasing the cost of the analysis. From that reason a full-field non-contact measurements, such as Digital Image Correlation (DIC), became very popular and valuable for analysis of structures subjected to mechanical loading and precise detection of the onset of strain localization. The presented study deals with tracking the strain localization using DIC in the case of masonry piers loaded by the combination of bending and compression. In such case the strain localizes into more compliant mortar joints while the complete collapse occurs when the masonry blocks fail to transfer tensile stress due to transversal expansion. The obtained data will be used for the validation of a finite element model to predict the behavior of masonry structures.

scholarly journals Bending fracture behavior of freestanding (Gd0.9Yb0.1)2Zr2O7 coatings by using digital image correlation and FEM simulation with 3D geometrical reconstruction

2019 ◽  
Vol 8 (4) ◽  
pp. 564-575 ◽  
Author(s):  
Weiguo Mao ◽  
Yujie Wang ◽  
Jun Shi ◽  
Huiyu Huang ◽  
Yuncheng Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Element Model ◽  
Image Correlation ◽  
Propagation Path ◽  
Correlation Technique ◽  
Bending Fracture

AbstractIt is important to investigate the mechanical performances of (Gd0.9Yb0.1)2Zr2O7 (GYbZ) materials deposited on irregular substrates for improving new thermal barrier coatings. Three-point bending fracture characteristics of freestanding GYbZ coating prepared by supersonic plasma sprayed (SPS) technique were investigated with the help of digital image correlation technique. The cracking time, crack propagation path, and mechanical properties of GYbZ coating were obtained. Meanwhile, the X-ray computed tomography technique was introduced to scan the microstructure of freestanding GYbZ coatings, which are used to establish three-dimensional (3D) finite element model by using the Avizo software. The brittle cracking criterion was applied to describe the bending fracture process of GYbZ coatings. The critical cracking strain was estimated as 0.36%±0.03% by repeatedly comparing the difference between the experimental and simulated curves. The results would be extended to predict the dangerous region and failure mechanisms of GYbZ coatings deposited on irregular substrate during finite element simulations.

scholarly journals Experimental Validation of a Voxel-Based Finite Element Model Simulating Femoroplasty of Lytic Lesions in the Proximal Femur

2021 ◽  
Author(s):  
Amelie Sas ◽  
An Sermon ◽  
G. Harry van Lenthe
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bone Cement ◽  
Proximal Femur ◽  
Correlation Coefficients ◽  
Element Model ◽  
Surface Strain ◽  
Image Correlation ◽  
Finite Element Models ◽  
Before And After

Abstract Femoroplasty is a procedure where bone cement is injected percutaneously into a weakened proximal femur. Uncertainty exists whether femoroplasty provides sufficient mechanical strengthening to prevent fractures in patients with femoral bone metastases. Finite element models are promising tools to evaluate the mechanical effectiveness of femoroplasty, but a thorough validation is required. This study validated a voxel-based finite element model against experimental data from eight pairs of human cadaver femurs with artificial metastatic lesions. One femur from each pair was left untreated, while the contralateral femur was augmented with bone cement. Finite element models accurately predicted the femoral strength in the defect (R² = 0.96) and augmented (R² = 0.93) femurs. The modelled surface strain distributions showed a good qualitative match with results from digital image correlation; yet, quantitatively, only moderate correlation coefficients were found for the defect (mean R² = 0.78) and augmented (mean R² = 0.76) femurs. This was attributed to the presence of vessel holes in the femurs and the jagged surface representation of our voxel-based models. Despite some inaccuracies in the surface measurements, the FE models accurately predicted the global bone strength and qualitative deformation behavior, both before and after femoroplasty. Hence, they can offer a useful biomechanical tool to assist clinicians in assessing the need for prophylactic augmentation in patients with metastatic bone disease, as well as in identifying suitable patients for femoroplasty.

scholarly journals Experimental Validation of Finite Element Models of Intact and Implanted Composite Hemipelvises Using Digital Image Correlation

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Rajesh Ghosh ◽  
Sanjay Gupta ◽  
Alexander Dickinson ◽  
Martin Browne
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Orthopedic Implants ◽  
Image Correlation ◽  
Fe Model ◽  
Acetabular Cup ◽  
Full Field ◽  
Strain Rosette

A detailed understanding of the changes in load transfer due to implantation is necessary to identify potential failure mechanisms of orthopedic implants. Computational finite element (FE) models provide full field data on intact and implanted bone structures, but their validity must be assessed for clinical relevance. The aim of this study was to test the validity of FE predicted strain distributions for the intact and implanted pelvis using the digital image correlation (DIC) strain measurement technique. FE models of an in vitro hemipelvis test setup were produced, both intact and implanted with an acetabular cup. Strain predictions were compared to DIC and strain rosette measurements. Regression analysis indicated a strong linear relationship between the measured and predicted strains, with a high correlation coefficient (R = 0.956 intact, 0.938 implanted) and a low standard error of the estimate (SE = 69.53 με, 75.09 με). Moreover, close agreement between the strain rosette and DIC measurements improved confidence in the validity of the DIC technique. The FE model therefore was supported as a valid predictor of the measured strain distribution in the intact and implanted composite pelvis models, confirming its suitability for further computational investigations.

Assessments on the mechanical behaviour of a monolithic composite structure instrumented with a monitoring patch

2017 ◽  
Vol 51 (26) ◽  
pp. 3597-3610 ◽  
Author(s):  
Mauricio Torres ◽  
Francis Collombet ◽  
Bernard Douchin ◽  
Laurent Crouzeix ◽  
Yves-Henri Grunevald
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Composite Structures ◽  
Composite Plate ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Element Model ◽  
Numerical Approach ◽  
Image Correlation

In this paper, the monitoring patch is evaluated as an alternative instrumentation technique for aircraft-type composite structures, by means of the Multi-Instrumented Technological Evaluator. In this case, the goal is to evaluate the strength and failure modes of a carbon-epoxy composite plate with two drop-offs instrumented with a monitoring patch. With the aid of finite element models, the testing of the plate under combined loads is analysed to have a first numerical approach of its behaviour. Then, the experimental campaign is accomplished by testing the plate with multi-instrumentation devices and techniques such as strain gauges and digital image correlation. A correct calculation/test correlation is achieved by comparing the strain values calculated by the finite element model and the experimental strain data acquired by gauges and digital image correlation. The results confronted provide a first evidence to quantify the influence of the monitoring patch on the mechanical performance of the composite plate. Therefore, it could be employed in the near future as instrumentation technique on large composite structures.

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