Subject-Specific p-FE Analysis of the Proximal Femur Utilizing Micromechanics-Based Material Properties

2008 ◽  
Vol 6 (5) ◽  
pp. 483-498 ◽  
Author(s):  
Zohar Yosibash ◽  
Nir Trabelsi ◽  
Christian Hellmich
Keyword(s):  
Proximal Femur ◽  
Material Properties ◽  
Fe Analysis ◽  
Subject Specific

Validation of subject-specific automated p-FE analysis of the proximal femur

2009 ◽  
Vol 42 (3) ◽  
pp. 234-241 ◽  
Author(s):  
Nir Trabelsi ◽  
Zohar Yosibash ◽  
Charles Milgrom
Keyword(s):  
Proximal Femur ◽  
Fe Analysis ◽  
Subject Specific

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

scholarly journals Sensitivity of the Stress Field of the Proximal Femur Predicted by CT‐based FE Analysis to Modeling Uncertainties

2021 ◽  
Author(s):  
Sina Youssefian ◽  
Jarred A. Bressner ◽  
Mikhail Osanov ◽  
James K. Guest ◽  
Wojciech B. Zbijewski ◽  
...  
Keyword(s):  
Stress Field ◽  
Proximal Femur ◽  
Fe Analysis ◽  
Modeling Uncertainties

Numerical Study of the Effect of Geometry and Boundary Conditions on the Collapse Behaviour of Stocky Stiffened Panels

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ultimate Strength ◽  
Material Properties ◽  
Finite Element Modelling ◽  
Numerical Study ◽  
Fe Analysis ◽  
Stiffened Panels ◽  
Element Modelling ◽  
Geometric Configurations

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

Sensitivity of Modeling Parameters in Proximal Femur Analyses

2000 ◽  
Author(s):  
Eric L. Wang ◽  
Yanyao Jiang ◽  
Lixia Fan ◽  
Brian Greer
Keyword(s):  
Hip Fracture ◽  
Proximal Femur ◽  
Material Properties ◽  
Applied Load ◽  
Loading Rate ◽  
Frictional Resistance ◽  
Fracture Load ◽  
Loading Direction ◽  
Structural Capacity ◽  
Femoral Geometry

Abstract Hip fracture risk can be quantified using a factor of risk (Hayes et al., 1996): (1) Φ = Applied load / Fracture load The structural capacity, the denominator, can be affected by many parameters including femoral geometry, material properties, load locations, loading direction, loading rate, and frictional resistance.

Fracture Prediction for the Proximal Femur Using Finite Element Models: Part I—Linear Analysis

1991 ◽  
Vol 113 (4) ◽  
pp. 353-360 ◽  
Author(s):  
J. C. Lotz ◽  
E. J. Cheal ◽  
W. C. Hayes
Keyword(s):  
Finite Element ◽  
Fracture Risk ◽  
Strain Gage ◽  
Proximal Femur ◽  
Material Properties ◽  
The United States ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Model Predictions

Over 90 percent of the more than 250,000 hip fractures that occur annually in the United States are the result of falls from standing height. Despite this, the stresses associated with femoral fracture from a fall have not been investigated previously. Our objectives were to use three-dimensional finite element models of the proximal femur (with geometries and material properties based directly on quantitative computed tomography) to compare predicted stress distributions for one-legged stance and for a fall to the lateral greater trochanter. We also wished to test the correspondence between model predictions and in vitro strain gage data and failure loads for cadaveric femora subjected to these loading conditions. An additional goal was to use the model predictions to compare the sensitivity of several imaging sites in the proximal femur which are used for the in vivo prediction of hip fracture risk. In this first of two parts, linear finite element models of two unpaired human cadaveric femora were generated. In Part II, the models were extended to include nonlinear material properties for the cortical and trabecular bone. While there was poor correspondence between strain gage data and model predictions, there was excellent agreement between the in vitro failure data and the linear model, especially using a von Mises effective strain failure criterion. Both the onset of structural yielding (within 22 and 4 percent) and the load at fracture (within 8 and 5 percent) were predicted accurately for the two femora tested. For the simulation of one-legged stance, the peak stresses occurred in the primary compressive trabeculae of the subcapital region. However, for a simulated fall, the peak stresses were in the intertrochanteric region. The Ward’s triangle (basicervical) site commonly used for the clinical assessment of osteoporosis was not heavily loaded in either situation. These findings suggest that the intertrochanteric region may be the most sensitive site for the assessment of fracture risk due to a fall and the subcapital region for fracture risk due to repetitive activities such as walking.

Dropped Object Analysis Using Non-Linear Dynamic FE Analysis

2014 ◽  
Author(s):  
Kwanghyun Ahn ◽  
Minsung Chun ◽  
Sangmin Han ◽  
Kibok Jang ◽  
Yongsuk Suh
Keyword(s):  
Material Properties ◽  
Failure Criteria ◽  
Offshore Structures ◽  
Linear Analysis ◽  
Fe Analysis ◽  
Structural Safety ◽  
Design Consideration ◽  
Linear Dynamic ◽  
Non Linear

For the last few decades, necessity of direct non-linear FE analysis has been increasing for the accidental events at the vessel/offshore structures. One of major areas for the accidental design, dropped object analysis using non-linear analysis is indispensable for the verification of structural safety at the design process. This paper is concerned with the methodology, conditions, and design consideration of dropped object analysis using dynamic FE analysis. By comparing the results from direct FE analyses to those from simplified energy method described in DNV-RP-C204, necessities and advantages of direct non-linear analysis can be verified. In this paper, the effect of analysis condition is investigated using parametric study. The results are influenced by the application of failure criteria according to the rule requirements, application of material properties, dropping position, condition of the object, and so on. This study can suggest appropriate determination of the methodology and condition for the dropped object analysis using direct FE analysis.

scholarly journals Mid-Term Results of Total Hip Arthroplasty Using A Three-Dimensional Porous Titanium Acetabular Cup: An Examination of Micromotion Using Subject-Specific Finite Element Analysis

2021 ◽  
Author(s):  
Takaki Miyagawa ◽  
Kazu Matsumoto ◽  
Shingo Komura ◽  
Haruhiko Akiyama
Keyword(s):  
Finite Element ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Three Dimensional ◽  
Porous Titanium ◽  
Fe Analysis ◽  
Total Hip ◽  
Radiolucent Lines ◽  
Subject Specific

Abstract Background: We investigated the mid-term clinical and radiological results of total hip arthroplasty (THA) using a three-dimensional (3D) porous titanium cup and analysed the micromotion at the interface of the cup using subject-specific finite element (FE) analysis. Methods: We evaluated 73 hips of 65 patients (6 men and 59 women; mean age at the time of surgery 62.2 years, range 45-86 years) who had undergone THA using a 3D porous titanium cup. Clinical evaluation was performed using the Japanese Orthopaedic Association (JOA) hip score system. We assessed the fixation of the acetabular component based on the presence of radiolucent lines and cup migration using anteroposterior radiographs. Subject-specific FE models were constructed from computed tomography data. Results: The JOA score improved from a preoperative mean of 52.2 (range, 23-82) to a mean of 87.8 (range, 71-100) at the final follow-up. None of the patients underwent revisions during the follow-up period. Radiolucent lines were observed in 26 cases (35.6%) and frequently appeared at DeLee and Charnley Zone 3. In the FE analysis, the micromotion at DeLee and Charnley Zone 3 was significantly larger than that at Zones 1 and 2. Furthermore, micromotion was large in the groups in which radiolucent lines appeared at Zone 3. Conclusions: The mid-term clinical outcome of THA using a 3D porous titanium cup was excellent. However, radiolucent lines frequently appeared at DeLee and Charnley Zone 3. FE analysis indicated that micromotion was large at the same site, strongly suggesting that it contributes to the emergence of radiolucent lines. The 3D porous titanium cups are useful in THA, and with improvements focused on micromotion, we anticipate better long-term outcomes.

scholarly journals Biomechanics of aging and osteoarthritic human knee ligaments

2021 ◽  
Author(s):  
Abby E Peters ◽  
Brendan Geraghty ◽  
Karl T Bates ◽  
Riaz Akhtar ◽  
Rosti Readioff ◽  
...  
Keyword(s):  
Knee Joint ◽  
Material Properties ◽  
Small Sample ◽  
Failure Stress ◽  
Knee Joints ◽  
Knee Ligaments ◽  
Human Knee ◽  
Subject Specific ◽  
Linear Force ◽  
And Cartilage

Background. Ligaments work to stabilize the human knee joint and prevent excessive movement. Whilst ligaments are known to decline in structure and function with aging, there has been no systematic effort to study changes in gross mechanical properties in the four major human knee ligaments due to osteoarthritis (OA). This study aims to collate material properties for the anterior (ACL) and posterior (PCL) cruciate ligaments, medial (MCL) and lateral (LCL) collateral ligaments. Our cadaveric samples come from a diverse demographic from which the effects of aging and OA on bone and cartilage material properties have already been quantified. Therefore, by combining our previous bone and cartilage data with the new ligament data from this study we are facilitating subject-specific whole-joint modelling studies. Methods. The demographics of the collected cadaveric knee joints were diverse with age range between 31 to 88 years old, and OA International Cartilage Repair Society grade 0 to 4. Twelve cadaveric human knee joints were dissected, and bone-ligament-bone specimens were extracted for mechanical loading to failure. Ligament material properties were determined from the load-extension curves, namely: linear and ultimate (failure) stress and strain, secant modulus, tangent modulus, and stiffness. Results. There were significant negative correlations between age and ACL linear force (p=0.01), stress (p=0.03) and extension (p=0.05), ACL failure force (p=0.02), stress (p=0.02) and extension (p=0.02), PCL secant (p=0.02) and tangent (p=0.02) modulus, and LCL stiffness (p=0.05). Significant negative correlations were also found between OA grades and ACL linear force (p=0.05), stress (p=0.02), extension (p=0.01) and strain (p=0.03), and LCL failure stress (p=0.05). However, changes in age or OA grade did not show a statistically significant correlation with the MCL tensile parameters. Trends showed that almost all the tensile parameters of the ACL and PCLs decreased with increasing age and progression of OA. Due to small sample size, the combined effect of age and presence of OA could not be statistically derived. Conclusions. This research is the first to correlate changes in tensile properties of the four major human knee ligaments to aging and OA. The current ligament study when combined with our previous findings on bone and cartilage for the same twelve knee cadavers, supports conceptualization of OA as a whole-joint disease that impairs the integrity of many peri-articular tissues within the knee. The subject-specific data pool consisting of the material properties of the four major knee ligaments, subchondral and trabecular bones and articular cartilage will aid reconstruction and graft replacements and advance knee joint finite element models, whilst knowledge of aged or diseased mechanics may direct future therapeutic interventions.

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