The Effect of the Frontal Plane Tibiofemoral Angle and Varus Knee Moment on the Contact Stress and Strain at the Knee Cartilage

2010 ◽  
Vol 26 (4) ◽  
pp. 432-443 ◽  
Author(s):  
Nicholas H. Yang ◽  
Paul K. Canavan ◽  
Hamid Nayeb-Hashemi
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Normal Stress ◽  
Frontal Plane ◽  
Stress And Strain ◽  
Normal Strain ◽  
Knee Cartilage ◽  
Element Analysis ◽  
Tibiofemoral Angle ◽  
The Individual

Subject-specific models were developed and finite element analysis was performed to observe the effect of the frontal plane tibiofemoral angle on the normal stress, Tresca shear stress and normal strain at the surface of the knee cartilage. Finite element models were created for three subjects with different tibiofemoral angle and physiological loading conditions were defined from motion analysis and muscle force mathematical models to simulate static single-leg stance. The results showed that the greatest magnitude of the normal stress, Tresca shear stress and normal strain at the medial compartment was for the varus aligned individual. Considering the lateral knee compartment, the individual with valgus alignment had the largest stress and strain at the cartilage. The present investigation is the first known attempt to analyze the effects of tibiofemoral alignment during single-leg support on the contact variables of the cartilage at the knee joint. The method could be potentially used to help identify individuals most susceptible to osteoarthritis and to prescribe preventive measures.

The Effect of the Frontal Plane Tibiofemoral Angle on the Stress and Strain at the Knee Cartilage During the Stance Phase of the Gait Cycle

2009 ◽  
Author(s):  
Nicholas Yang ◽  
Hamid Nayeb-Hashemi ◽  
Paul Canavan
Keyword(s):  
Stance Phase ◽  
Gait Cycle ◽  
Frontal Plane ◽  
Magnetic Resonance Images ◽  
Medial Compartment ◽  
Stress And Strain ◽  
Normal Strain ◽  
Varus Knee ◽  
Knee Cartilage ◽  
Tibiofemoral Angle

Three-dimensional (3-D) finite element analysis (FEA) knee models were created to determine the effect of the frontal plane tibiofemoral angle on the stress and strain at the knee cartilage during the stance phase of the gait cycle. Knee models of three healthy subjects of different tibiofemoral angles and weight were created from sagittal view magnetic resonance images (MRI) of the knee. The loading conditions were determined from motion analysis and force platform data and a muscle force reduction model. During the stance phase, the subjects exhibited a valgus-varus-valgus knee moment pattern that determined the location and magnitude of the maximum stress and strain in the cartilage on the lateral or medial compartment of the knee. The highest values of the normal stress, Tresca shear stress and normal strain for each subject occurred at 25% of the stance phase of the gait cycle, where the maximum compressive load and varus knee moment occurred. The individual with the varus aligned knee had the largest stress and strain at the medial compartment of the knee compared to the normal aligned and valgus aligned individuals due to the larger varus knee moment exhibited during the stance phase of the gait cycle in the varus aligned individual. The results from the FEA data may be used by health care professional to identify individuals most susceptible to knee osteoarthritis (OA) and assist in developing preventive measure to slow and possibly stop the initiation and progression of OA.

Investigation of Design Parameters and Failure Criteria of O-Ring Seal Structure

2005 ◽  
Author(s):  
Dianyin Hu ◽  
Rongqiao Wang ◽  
Quanbin Ren ◽  
Jie Hong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Stress ◽  
Normal Stress ◽  
Maximum Shear Stress ◽  
Design Parameters ◽  
Element Analysis ◽  
Axisymmetric Model ◽  
Sealing Performance ◽  
Maximum Contact

First, this paper established the seal structural 2D axisymmetric model of a certain Solid Rocket Booster (SRB) and calculated the deformation and stresses at ignition through a large displacement, incompressible, contact finite element analysis. The results show that the maximum contact stress appears at the contact area and the maximum shear stress at groove notch. Then, some typical parameters of the seal structure which might have the impact on the sealing performance, such as the gap breadth, initial compressibility, fillets of the groove notch and bottom, groove width, were analyzed. We can find that the gap breadth and initial compressibility do great contributions to the maximum contact normal stress, and the groove notch and bottom fillets act upon the maximum shear stress obviously. In order to verify the validity of the 2D axisymmetric model, 3D structural finite element analysis of the structure was conducted, and the results indicate that in service, the upper flange is inclined relative to the nether flange, which seems to mean that the gap breadth can not be considered as a constant during the 2D axisymmetric analysis. However further calculations say that if using the minimum gap breadth gotten in 3D analysis as its constant gap value, the above 2D axisymmetric model can rationally take the place of 3D model to analyze the sealing performance. Finally, the failure modes & criteria of the O-ring seals based on the maximum contact normal stress and shear stress were determined to ensure the reliability of this structure.

Method to Determine the Effect of the Frontal Plane Tibiofemoral Knee Angle on the Varus-Valgus Moment at the Knee During Stance and Gait

2008 ◽  
Author(s):  
Paul K. Canavan ◽  
Nicholas H. Yang ◽  
Hamid Nayeb-Hashemi
Keyword(s):  
Load Distribution ◽  
Frontal Plane ◽  
Element Model ◽  
Analysis Procedure ◽  
Stress And Strain ◽  
Knee Angle ◽  
Knee Cartilage ◽  
Tibiofemoral Angle ◽  
Tibiofemoral Alignment ◽  
Biomechanical Factors

Osteoarthritis (OA) is a degenerative disease of articular cartilage that affects millions of people [1]. Local biomechanical factors may severely affect initiation and progression of OA due to changes in loading conditions at the cartilage. The frontal plane tibiofemoral alignment effects the varus/valgus moment which could increase the overall loading at the knee. Biomechanical studies have reported that the varus moment is a key determinant in the load distribution at the knee [2, 3] and has been linked to OA progression [4, 5]. A normal knee will have a tibiofemoral angle approximately 7° valgus [6]. Deviation from this angle leads to a knee joint with a varus or valgus condition. In this investigation, a motion analysis procedure was developed to determine the affect of the frontal plane tibiofemoral angle on the force and moment reactions at the knee. The results of these methods could be utilized in a subject specific finite element model to determine the stress and strain at the knee cartilage and to suggest measures to prevent OA.

scholarly journals Effect of frontal plane tibiofemoral angle on the stress and strain at the knee cartilage during the stance phase of gait

2010 ◽  
Vol 28 (12) ◽  
pp. 1539-1547 ◽  
Author(s):  
Nicholas H. Yang ◽  
Hamid Nayeb-Hashemi ◽  
Paul K. Canavan ◽  
Ashkan Vaziri
Keyword(s):  
Stance Phase ◽  
Frontal Plane ◽  
Stress And Strain ◽  
Knee Cartilage ◽  
Tibiofemoral Angle

scholarly journals Analisa Kekuatan Struktur Barge Pada Proses Load Out Offshore Module (Top Side) dengan SPMT

2020 ◽  
pp. 1-5
Author(s):  
Habibi Palippui ◽  
Sahwan Ramadhan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Stress ◽  
Normal Stress ◽  
Element Analysis

Salah satu proses yang kritikal ketika fabrikasi offshore yaitu proses transfer offshore module (Top Side) dari atas jetty ke atas transportation barge atau sering disebut Proses Load Out. Salah satu analisa yang dibutuhkan untuk memastikan proses load out berjalan dengan lancar dan aman yaitu analisa kekuatan struktur barge pada saat proses load out tersebut terjadi yaitu dimana dilakukan pengecekan terhadap kekuatan struktur barge apakah mampu menahan beban top side ketika terjadi transfer beban dari atas jetty ke atas transportation barge atau dari tepi barge sampai ke final lokasi. Untuk mendapatkan hasil yang akurat maka digunakan bantuan program komputer atau sering disebut dengan metode elemen hingga (Finite Element Analysis). Adapun software yang digunakan pada analisa ini yaitu StaadPro V8i dengan simulasi percobaan ada tiga module. Dari hasil analisa diperoleh kesimpulan bahwa simulasi percobaan module tiga memiliki  nilai maksimum von misses stress adalah 74,119 N/mm2, normal stress adalah 57,765 N/mm2, dan shear stress adalah 0,02279 N/mm2, dimana semua nilai tegangan tersebut dibawah tegangan izin atau dibawah batas maksimal yang disyaratkan AISC sehingga struktur barge tidak perlu diberikan tambahan penguatan baik internal maupun eksternal  karena masih aman dan mampu untuk menahan beban top side ketika load. Analisis dengan SPMT berpotensi menjadi patokan dalam dalam menganalisis kekuatan struktrur barge dalam proses load out offshore module (top side).

Finite Element Analysis of the Knee: The Effect of Tibiofemoral Alignment and Weight on the Stresses in the Knee

2008 ◽  
Author(s):  
N. H. Yang ◽  
H. N. Hashemi ◽  
P. Canavan
Keyword(s):  
Finite Element Analysis ◽  
Load Distribution ◽  
Mechanical Axis ◽  
Frontal Plane ◽  
Varus Knee ◽  
Knee Cartilage ◽  
Element Analysis ◽  
Tibiofemoral Angle ◽  
Tibiofemoral Alignment ◽  
Biomechanical Factors

Osteoarthritis (OA) is a degenerative disease of articular cartilage that affects millions of people [1]. Local biomechanical factors may severely affect the initiation and progression of OA due to changes in loading conditions at the knee cartilage. Body weight and the frontal plane tibiofemoral alignment are two biomechanical factors that could increase the overall loading at the knee. A normal knee will have a tibiofemoral angle approximately 7° valgus [2]. Deviation from this angle leads to a knee joint with a varus or valgus condition. The tibiofemoral angle is measured by the intersection made between the mechanical axis of the femur and the tibia in the frontal plane and affects the magnitude of the varus knee moment, Fig. 1A. Biomechanical studies have shown the varus moment is a key determinant in the load distribution at the knee [3, 4], Fig. 1A, and has been linked to OA progression [5, 6].

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

Finite Element Analysis of Motor Box for EBZ160 Horizontal Roadheader

2015 ◽  
Vol 1090 ◽  
pp. 233-237
Author(s):  
Ji Jun Miao ◽  
Ri Sheng Long
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optimal Design ◽  
Safety Factor ◽  
Stress And Strain ◽  
Element Analysis

In order to solve the cracking and poor reliability problems of motor box of Horizontal Roadheader, the static structural FEA (Finite Element Analysis) of cutting arm & motor box of the EBH160 Horizontal Roadheader was conducted, and the stress and strain contours of FEA were obtained. By comparing the calculated results, the safety factor of cutting arm & motor box was 1.36, which provides a reference for the optimal design of cutting arm & motor box.

Stress in Bonded Adherends for Single Lap Joints

1996 ◽  
Vol 12 (03) ◽  
pp. 167-171
Author(s):  
G. Bezine ◽  
A. Roy ◽  
A. Vinet
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Numerical Model ◽  
Stress Distribution ◽  
Normal Stress ◽  
Lap Joints ◽  
Axial Loads ◽  
Normal Stress Distribution ◽  
Single Lap Joints ◽  
Element Technique

A finite-element technique is used to predict the shear stress and normal stress distribution in adherends for polycarbonate/polycarbonate single lap joints subjected to axial loads. Numerical and photoelastic results are compared so that a validation of the numerical model is obtained. The influences on stresses of the overlap length and the shape of the adherends are studied.

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