Comparison of isotropic and orthotropic material property assignments on femoral finite element models under two loading conditions

2007 ◽  
Vol 29 (8) ◽  
pp. 935 ◽  
Author(s):  
Vaclav Baca ◽  
Zdenek Horak
Keyword(s):  
Finite Element ◽  
Material Property ◽  
Orthotropic Material ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Orthotropic Material Property

Development of Simplified Spot Weld Models: Stiffness Prediction and Computational Performance Evaluation

2010 ◽  
Author(s):  
Noman Khandoker ◽  
Monir Takla ◽  
Thomas Ting
Keyword(s):  
Finite Element ◽  
Spot Weld ◽  
Finite Element Models ◽  
Suitable Model ◽  
Loading Conditions ◽  
Computational Costs ◽  
Automotive Body ◽  
Simple Strategy ◽  
Pull Out ◽  
Computational Performance

Simple spot weld connection models are desirable in huge and complicated finite element models of automotive body-in-white structures which generally contains thousands of spot weld joints. Hence, in this paper six different individual spot weld joint finite element models simplified in terms of their geometric and constitutive representations were developed including the one that is currently used in automotive industries. The stiffness characteristics of these developed models were compared with the experimental results obtained following a simple strategy to design the welded joint based on the desired mode of nugget pull out failure. It was found that the current spot weld modeling practice in automotive industry under predict the maximum joint strength nearly by 50% for different loading conditions. The computational costs incurred by the developed models in different loading conditions were also compared. Hence, a suitable model for spot welded joints is established which is very simple to develop but relatively cheap in terms of computational costs.

scholarly journals The effects of femoral metaphyseal morphology on growth plate biomechanics in juvenile chimpanzees and humans

2021 ◽  
Vol 11 (5) ◽  
pp. 20200092
Author(s):  
Peter A. Stamos ◽  
Michael A. Berthaume
Keyword(s):  
Finite Element ◽  
Surface Morphology ◽  
Growth Plate ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Locomotor Behaviour ◽  
Knee Loading ◽  
Subject Specific ◽  
Von Mises ◽  
Von Mises Stresses

The distal femoral metaphyseal surface presents dramatically different morphologies in juvenile extant hominoids—humans have relatively flat metaphyseal surfaces when compared with the more complex metaphyseal surfaces of apes. It has long been speculated that these different morphologies reflect different biomechanical demands placed on the growth plate during locomotor behaviour, with the more complex metaphyseal surfaces of apes acting to protect the growth plate during flexed-knee behaviours like squatting and climbing. To test this hypothesis, we built subject-specific parametric finite-element models from the surface scans of the femora of five Pan and six Homo juveniles. We then simulated the loading conditions of either a straight-leg or flexed-knee gait and measured the resulting stresses at the growth plate. When subjected to the simulated flexed-knee loading conditions, both the maximum and mean von Mises stresses were significantly lower in the Pan models than in the Homo models. Further, during these loading conditions, von Mises stresses were strongly negatively correlated with ariaDNE, a measure of complexity of the metaphyseal surface. These results indicate that metaphyseal surface morphology has a robust effect on growth plate mechanics.

EVALUATING THE EFFECT OF VARIOUS MENISCAL ATTACHMENTS AND MATERIAL PROPERTIES ON FEMORAL BONE STRESS

2018 ◽  
Vol 21 (01) ◽  
pp. 1850003
Author(s):  
Lance L. Frazer ◽  
Kenneth J. Fischer
Keyword(s):  
Finite Element ◽  
Material Property ◽  
Material Properties ◽  
Finite Element Models ◽  
Femoral Bone ◽  
Bone Stress ◽  
Stifle Joint ◽  
Meniscal Attachments ◽  
Property Changes ◽  
The Relationship

In this paper, several finite element models of an equine stifle joint with varying meniscal properties and attachments are compared to understand the effects of meniscal attachment complexity and material property changes on bone stresses. We found that the complexity in the meniscal attachment is critical when evaluating tensile stresses in the bone. We also demonstrate that simplified material properties may be justified when the relationship between each material property and the desired output variables is well understood. The choice of the most efficient, and yet appropriate, meniscal modeling method depends on the goals of the model.

The Analysis on Structure of U-Shaped Compartment Based on Soil Mechanics Principle

2011 ◽  
Vol 117-119 ◽  
pp. 1847-1850
Author(s):  
Feng Yuan Wang ◽  
Chuan Yuan Wang ◽  
Peng Guo ◽  
Qi Cao
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Soil Mechanics ◽  
Shell Element ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Compartment Analysis

According to the project requirements, U-shaped compartment was designed and analysed based on soil mechanics principle. The finite element models of U-shaped compartment structure were established, shell element was employed to mesh compartment. Analysis on the structure of the compartment against typical loading conditions was carried out to get the stress distribution of the compartment structure.

Towards a Failure Criterion for Microtubules Based on Matching Strength Analysis in Finite Element Models to AFM Loads

2011 ◽  
Author(s):  
William Taylor ◽  
W. Steve Shepard ◽  
Candace L. Floyd
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Brain Injury ◽  
Failure Criterion ◽  
Point Load ◽  
Strength Analysis ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Starting Point ◽  
The Impact

In previous research studies, the geometric and elastic properties for a critical component of axon health, the microtubule (MT), have been determined using lateral indentation with the tip of an atomic force microscope (AFM). Although the response due to the indentations caused by the AFM was observed to be linear for most of the tests, forces greater than 300pN would result in a permanent irreversible collapse of the MT’s structure. While the intent of those researchers was not to evaluate microtubule strength properties, that load can be used as a starting point to evaluate internal stress failure criterion for such structures. To that end, the current research is investigating MT strength by replicating the loading and boundary conditions in a finite element model. This work is an extension of previous work aimed at using this 300 pN point load to develop failure criteria for MTs under more realistic loading conditions. In the present work, modeling has been used to correlate the AFM point load response with the more realistic distributed loading conditions that would result during a brain injury event. Furthermore, the impact of nearby MTs on the stresses that occur under similar loading conditions is also examined. These results are being used to analytically determine a stress threshold related to MT structural failure. Correspondingly, models that include dynamic wave propagation through the microtubule will be studied. The failure criterion determined in both cases would aid in evaluating brain injury studies that involve pressure wave propagation in whole-head finite element models, even when such models represent the white matter using homogeneous properties.

Stresses in the Growth Plate of the Developing Proximal Femur

2001 ◽  
Vol 17 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Thomas G. Ribble ◽  
Michael H. Santare ◽  
Freeman Miller
Keyword(s):  
Finite Element ◽  
Growth Plate ◽  
Proximal Femur ◽  
Normal Development ◽  
Normal Activity ◽  
Shear Stresses ◽  
Finite Element Models ◽  
Loading Conditions ◽  
Neck Shaft Angle ◽  
Shaft Angle

Finite element models of the proximal femur at birth, 2 years of age, and at 8 years of age were constructed to investigate stress patterns under different loading conditions. These loading conditions represent typical activities of a normal developing child and abnormal activity associated with muscle spasticity. The hypothesis is that the shear stresses in the growth plate correlate with the neckshaft angle as associated with valgus and normal development. Loads for the finite element models were derived from a separate muscle model used to calculate the forces across the hip joint for an arbitrary subject and activity. Results show there is an inverse relationship between the relative magnitude of the shear stress in the growth plate and the developing neck-shaft angle. The relatively high shear stresses generated by normal activity in the 2-year-old’s growth plate correlate with the decrease in neck-shaft angle that accompanies normal development. Alternatively, lower shear stresses are generated in the growth plate by loading conditions representing spasticity. These lower magnitude shear stresses correlate with a valgus deformity, which is often observed clinically.

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