scholarly journals A quasi-brittle continuum damage finite element model of the human proximal femur based on element deletion

2012 ◽  
Vol 51 (1-2) ◽  
pp. 219-231 ◽  
Author(s):  
Ridha Hambli
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Proximal Femur ◽  
Element Model ◽  
Continuum Damage

scholarly journals Failure Analysis of Composite Pinned Joints Based on Continuum Damage Mechanics

2018 ◽  
Vol 36 (5) ◽  
pp. 848-855
Author(s):  
Hongliang Tuo ◽  
Xiaoping Ma ◽  
Zhixian Lu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Fracture Plane ◽  
Continuum Damage ◽  
Bearing Strength ◽  
Matrix Damage ◽  
Pinned Joints

The paper conducted bearing tests on composite pinned joints with four different stacking sequences. The bearing strength and bearing chord stiffness were obtained. The influence of stacking sequences on failure modes, bearing strength and bearing chord stiffness was discussed. Based on continuum damage mechanics, a three-dimensional finite element model of composite pinned joint under bearing load was built, where the maximum strain criterion was employed for initiation and bi-liner damage constitutive relation for revolution of fiber damage, while the physical-based Puck criterion was used for matrix damage initiation, and matrix damage revolution depended on the effective strain on the fracture plane. The failure mode, bearing strength and bearing chord stiffness of composite pinned joint were discussed with this model under which the non-linear shear behavior and in-situ strength effects were considered. Good agreements between test results and numerical simulations validates the accuracy and applicability of the finite element model.

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.

Virtual characterization of nonlocal continuum damage model parameters using a high fidelity finite element model

2021 ◽  
Vol 256 ◽  
pp. 113073
Author(s):  
Johannes Reiner ◽  
Xiaodong Xu ◽  
Navid Zobeiry ◽  
Reza Vaziri ◽  
Stephen R. Hallett ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Model ◽  
Element Model ◽  
Model Parameters ◽  
High Fidelity ◽  
Continuum Damage ◽  
Nonlocal Continuum ◽  
Continuum Damage Model

A Biomechanical and Finite Element Analysis of Femoral Neck Notching During Hip Resurfacing

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Edward T. Davis ◽  
Michael Olsen ◽  
Rad Zdero ◽  
Marcello Papini ◽  
James P. Waddell ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Neck ◽  
Finite Element Model ◽  
Proximal Femur ◽  
Equivalent Stress ◽  
Element Model ◽  
Hip Resurfacing ◽  
Stress And Strain ◽  
Element Analysis

Hip resurfacing is an alternative to total hip arthroplasty in which the femoral head surface is replaced with a metallic shell, thus preserving most of the proximal femoral bone stock. Accidental notching of the femoral neck during the procedure may predispose it to fracture. We examined the effect of neck notching on the strength of the proximal femur. Six composite femurs were prepared without a superior femoral neck notch, six were prepared in an inferiorly translated position to create a 2 mm notch, and six were prepared with a 5 mm notch. Six intact synthetic femurs were also tested. The samples were loaded to failure axially. A finite element model of a composite femur with increasing superior notch depths computed maximum equivalent stress and strain distributions. Experimental results showed that resurfaced synthetic femurs were significantly weaker than intact femurs (mean failure of 7034 N, p<0.001). The 2 mm notched group (mean failure of 4034 N) was significantly weaker than the un-notched group (mean failure of 5302 N, p=0.018). The 5 mm notched group (mean failure of 2808 N) was also significantly weaker than both the un-notched and the 2 mm notched groups (p<0.001, p=0.023, respectively). The finite element model showed the maximum equivalent strain in the superior reamed cancellous bone increasing with corresponding notch size. Fracture patterns inferred from equivalent stress distributions were consistent with those obtained from mechanical testing. A superior notch of 2 mm weakened the proximal femur by 24%, and a 5 mm notch weakened it by 47%. The finite element analysis substantiates this showing increasing stress and strain distributions within the prepared femoral neck with increasing notch depth.

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