Comparison of femur strain under different loading scenarios: Experimental testing

2020 ◽  
Vol 235 (1) ◽  
pp. 17-27
Author(s):  
Ievgen Levadnyi ◽  
Jan Awrejcewicz ◽  
Yan Zhang ◽  
Yaodong Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Distribution ◽  
Element Model ◽  
Surface Strain ◽  
Image Correlation ◽  
Loading Conditions ◽  
Bone Implant ◽  
Bone Stiffness

Bone fracture, formation and adaptation are related to mechanical strains in bone. Assessing bone stiffness and strain distribution under different loading conditions may help predict diseases and improve surgical results by determining the best conditions for long-term functioning of bone-implant systems. In this study, an experimentally wide range of loading conditions (56) was used to cover the directional range spanned by the hip joint force. Loads for different stance configurations were applied to composite femurs and assessed in a material testing machine. The experimental analysis provides a better understanding of the influence of the bone inclination angle in the frontal and sagittal planes on strain distribution and stiffness. The results show that the surface strain magnitude and stiffness vary significantly under different loading conditions. For the axial compression, maximal bending is observed at the mid-shaft, and bone stiffness is also maximal. The increased inclination leads to decreased stiffness and increased magnitude of maximum strain at the distal end of the femur. For comparative analysis of results, a three-dimensional, finite element model of the femur was used. To validate the finite element model, strain gauges and digital image correlation system were employed. During validation of the model, regression analysis indicated robust agreement between the measured and predicted strains, with high correlation coefficient and low root-mean-square error of the estimate. The results of stiffnesses obtained from multi-loading conditions experiments were qualitatively compared with results obtained from a finite element analysis of the validated model of femur with the same multi-loading conditions. When the obtained numerical results are qualitatively compared with experimental ones, similarities can be noted. The developed finite element model of femur may be used as a promising tool to estimate proximal femur strength and identify the best conditions for long-term functioning of the bone-implant system in future study.

Strain distribution in cruciform specimens subjected to biaxial loading conditions. Part 1: Two-dimensional versus three-dimensional finite element model

2010 ◽  
Vol 29 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Ebrahim Lamkanfi ◽  
Wim Van Paepegem ◽  
Joris Degrieck ◽  
Carla Ramault ◽  
Andreas Makris ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Distribution ◽  
Biaxial Loading ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
Loading Conditions ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

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.

A 3D efficient finite element model to simulate rolling contact fatigue under high loading conditions

2018 ◽  
Vol 126 ◽  
pp. 258-269 ◽  
Author(s):  
Zamzam Golmohammadi ◽  
Aditya Walvekar ◽  
Farshid Sadeghi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Element Model ◽  
Rolling Contact ◽  
High Loading ◽  
Loading Conditions

Multi-Scale Finite Element Model Development for Long-Term Condition Assessment of Vertical Lift Bridge

2018 ◽  
Author(s):  
Maryam Mashayekhizadeh ◽  
Milad Mehrkash ◽  
Vahid Shahsavari ◽  
Erin Santini-Bell
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Development ◽  
Element Model ◽  
Condition Assessment ◽  
Term Condition ◽  
Multi Scale ◽  
Vertical Lift

The Finite Element Method: A Tool to Evaluate Shear Bond Strength of Dental Bracket

2014 ◽  
Vol 984-985 ◽  
pp. 431-437
Author(s):  
Vijaykumar Hiremath ◽  
Girija Bidarimath ◽  
Basavaraj Endigeri
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Element Model ◽  
Loading Conditions ◽  
Acceptable Error ◽  
Three Dimensional Finite Element ◽  
Element Method

In this paper finite element model of steel dental bracket is generated along with bonding agent, enamel & stress analysis is carried out on the bracket for different loading conditions. Three dimensional finite element model developed are constrained with boundary condition that resembles to the reality. The Vonmisses stress is recorded for each loading conditions and compared with experimental results. The experimental work for 60 samples were carried out on Universal testing machine at material testing laboratory, Basaveshwar Engineering College, Bagalkot. It is found from FEM results that the shear bonding strength for different loadings from 60 N to 80 N varies from 7.276 N/mm2 to 9.7N/mm2, which are closer to experimental values with acceptable error. The study reveals that Finite Element Method can be used as a strong tool to analyze the dental bracket and study different parameters to improve its performance and to avoid time and cost required for experimentation.

Finite element model for the long-term behaviour of composite steel-concrete push tests

2010 ◽  
Vol 10 (1) ◽  
pp. 45-67 ◽  
Author(s):  
O. Mirza ◽  
B. Uy
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Composite Steel

Thermal Analysis of a Ball-Screw System

2012 ◽  
Vol 591-593 ◽  
pp. 818-826 ◽  
Author(s):  
Chin Chung Wei ◽  
Jeng Haur Horng ◽  
Jen Fin Lin
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Model ◽  
High Speed ◽  
Element Model ◽  
Surface Strain ◽  
Ball Screw ◽  
Control Factor ◽  
Positioning Error ◽  
Positioning Control

High speed ball-screw system has serious friction heat to form thermal expansion to each component. An analyzing model considering with contact deformation and thermal expansion is established in realizing positioning error for a high speed ball-screw system. A finite element model of nut is also built in calculating elongation of nut. Surface strain of nut is measured by strain gages in order to confirm with data obtained from finite element model. Temperature of nut and screw were also measured by thermal couples and are used in calculation of elongation by the use of linear elongation equation. The tendency of positioning error is well estimated by the analyzing model. The model can be used in feedback positioning control factor and develop precision high speed ball-screw system.

scholarly journals Study on validation method for femur finite element model under multiple loading conditions

2018 ◽  
Vol 322 ◽  
pp. 022061
Author(s):  
Fengjiao Guan ◽  
Guanjun Zhang ◽  
Jie Liu ◽  
Shujing Wang ◽  
Xu Luo
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Loading Conditions ◽  
Validation Method ◽  
Multiple Loading

scholarly journals Sensitivity Analysis of a Nuclear Reactor System Finite Element Model

2018 ◽  
Author(s):  
Gregory A. Banyay ◽  
Stephen D. Smith ◽  
Jason S. Young
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Surrogate Model ◽  
Computational Design ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Physical Parameters ◽  
Loading Conditions ◽  
Pressurized Water

The structures associated with the nuclear steam supply system (NSSS) of a pressurized water reactor (PWR) warrant evaluation of various non-stationary loading conditions which could occur over the life of a nuclear power plant. These loading conditions include those associated with a loss of coolant accident and seismic event. The dynamic structural system is represented by a finite element model consisting of significant epistemic and aleatory uncertainties in the physical parameters. To provide an enhanced understanding of the influence of these uncertainties on model results, a sensitivity analysis is performed. This work demonstrates the construction of a computational design of experiment which runs the finite element model a sufficient number of times to train and verify a unique aggregate surrogate model. Adaptive sampling is employed in order to reduce the overall computational burden. The surrogate model is then used to perform both global and local sensitivity analyses.

Finite Element Model for Analysis of Time-Dependent Behaviour of Concrete-Filled Steel Tubular Arches

2014 ◽  
Vol 553 ◽  
pp. 606-611
Author(s):  
Kai Luo ◽  
Yong Lin Pi ◽  
Wei Gao ◽  
Mark A. Bradford
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Nonlinear Analysis ◽  
Element Model ◽  
Time Dependent ◽  
Concrete Core ◽  
Time Dependent Behaviour ◽  
Linear And Nonlinear ◽  
Dependent Behaviour

This paper presents a finite element model for the linear and nonlinear analysis of time-dependent behaviour of concrete-filled steel tubular (CFST) arches. It is known when a CFST arch is subjected to a sustained load, the visco-elastic effects of creep in the concrete core will result in significant increases of the deformations and internal forces in the long-term. In this paper, a finite element model is developed using the age-adjusted effective modulus method to describe the creep behaviour of the concrete core. The finite element results of long-term displacement and stress redistribution agree very well with their analytical counterparts. The finite element model is then used to compare the linear and nonlinear results for the long-term behaviour of shallow CFST arches. It is demonstrated that the linear analysis underestimates the long-term deformations and internal force significantly and that to predict the time-dependent behaviour shallow CFST arches accurately, the nonlinear analysis is essential.

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