3D Finite Element Model of Meniscectomy: Changes in Joint Contact Behavior

2005 ◽  
Vol 128 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Barbara Zielinska ◽  
Tammy L. Haut Donahue

The goal of this study is to quantify changes in knee joint contact behavior following varying degrees of the medial partial meniscectomy. A previously validated 3D finite element model was used to simulate 11 different meniscectomies. The accompanying changes in the contact pressure on the superior surface of the menisci and tibial plateau were quantified as was the axial strain in the menisci and articular cartilage. The percentage of medial meniscus removed was linearly correlated with maximum contact pressure, mean contact pressure, and contact area. The lateral hemi-joint was minimally affected by the simulated medial meniscectomies. The location of maximum strain and location of maximum contact pressure did not change with varying degrees of partial medial meniscectomy. When 60% of the medial meniscus was removed, contact pressures increased 65% on the remaining medial meniscus and 55% on the medial tibial plateau. These data will be helpful for assessing potential complications with the surgical treatment of meniscal tears. Additionally, these data provide insight into the role of mechanical loading in the etiology of post-meniscectomy osteoarthritis.

Author(s):  
A A Besong ◽  
R Lee ◽  
R Farrar ◽  
Z M Jin

The contact mechanics of a novel metal-on-metal total hip replacement (THR) were investigated in this study. The metal-on-metal prosthesis considered consists of a cobalt-chrome acetabular insert connected to a titanium shell through a taper contact, articulating against a cobalt-chrome femoral head. Both the experimental measurement of the displacement of the acetabular insert and the contact area between the two bearing surfaces, and the corresponding numerical predictions using the finite element method have been conducted. Excellent agreement has been demonstrated between the experimental measurement and the finite element prediction under various loads up to 3 kN. The maximum contact pressure at the articulating surfaces has been predicted to be about 31 MPa from a simple axisymmetric finite element model, significantly lower than that of a similar cup but with a monoblock construct. This has been mainly attributed to the flexibility of the insert, leading to an increase in the conformity between the femoral head and the acetabular insert. In addition, the predicted maximum contact pressure is only slightly increased to 37 MPa, from a more realistic three-dimensional anatomical finite element model. The design features on metal-on-metal THRs have been shown to reduce contact stresses and may improve tribological performances of these hard-on-hard bearing couples.


1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.


2019 ◽  
Vol 13 (2) ◽  
pp. 181-188
Author(s):  
Meng Liu ◽  
Guohe Li ◽  
Xueli Zhao ◽  
Xiaole Qi ◽  
Shanshan Zhao

Background: Finite element simulation has become an important method for the mechanism research of metal machining in recent years. Objective: To study the cutting mechanism of hardened 45 steel (45HRC), and improve the processing efficiency and quality. Methods: A 3D oblique finite element model of traditional turning of hardened 45 steel based on ABAQUS was established in this paper. The feasibility of the finite element model was verified by experiment, and the influence of cutting parameters on cutting force was predicted by single factor experiment and orthogonal experiment based on simulation. Finally, the empirical formula of cutting force was fitted by MATLAB. Besides, a lot of patents on 3D finite element simulation for metal machining were studied. Results: The results show that the 3D oblique finite element model can predict three direction cutting force, the 3D chip shape, and other variables of metal machining and the prediction errors of three direction cutting force are 5%, 9.02%, and 8.56%. The results of single factor experiment and orthogonal experiment are in good agreement with similar research, which shows that the model can meet the needs for engineering application. Besides, the empirical formula and the prediction results of cutting force are helpful for the parameters optimization and tool design. Conclusion: A 3D oblique finite element model of traditional turning of hardened 45 steel is established, based on ABAQUS, and the validation is carried out by comparing with experiment.


2021 ◽  
Vol 62 ◽  
pp. 302-312
Author(s):  
Ninggang Shen ◽  
Avik Samanta ◽  
Wayne W. Cai ◽  
Teresa Rinker ◽  
Blair Carlson ◽  
...  

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1644
Author(s):  
Qian Zhang ◽  
Huijuan Liu ◽  
Tengfei Song ◽  
Zhenyang Zhang

A novel, improved equivalent circuit model of double-sided linear induction motors (DLIMs) is proposed, which takes the skin effect and the nonzero leakage reactance of the secondary, longitudinal, and transverse end effects into consideration. Firstly, the traditional equivalent circuit with longitudinal and transverse end effects are briefly reviewed. Additionally, the correction coefficients for longitudinal and transverse end effects derived by one-dimensional analysis models are given. Secondly, correction factors for skin effect, which reflects the inhomogeneous air gap magnetic field vertically, and the secondary leakage reactance are derived by the quasi-two-dimensional analysis model. Then, the proposed equivalent circuit is presented, and the excitation reactance and secondary resistance are modified by the correction coefficients derived from the three analytical models. Finally, a three-dimensional (3D) finite element model is used to verify the proposed equivalent circuit model under varying air gap width and frequency, and the results are also compared with that of the traditional equivalent circuit models. The calculated thrust characteristics by the proposed equivalent circuit and 3D finite element model are experimentally validated under a constant voltage–frequency drive.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaohui Zhang ◽  
Shuo Yuan ◽  
Jun Wang ◽  
Bagen Liao ◽  
De Liang

Abstract Background Recent studies have pointed out that arthroscopy, the commonly-used surgical procedure for meniscal tears, may lead to an elevated risk of knee osteoarthritis (KOA). The biomechanical factors of KOA can be clarified by the biomechanical analysis after arthroscopic partial meniscectomy (APM). This study aimed to elucidate the cartilage stress and meniscus displacement of the tibiofemoral joint under flexion and rotation loads after APM. Methods A detailed finite element model of the knee bone, cartilage, meniscus, and major ligaments was established by combining computed tomography and magnetic resonance images. Vertical load and front load were applied to simulate different knee buckling angles. At the same time, by simulating flexion of different degrees and internal and external rotations, the stresses on tibiofemoral articular cartilage and meniscus displacement were evaluated. Results Generally, the contact stress on both the femoral tibial articular cartilage and the meniscus increased with the increased flexion degree. Moreover, the maximum stress on the tibial plateau gradually moved backward. The maximum position shift value of the lateral meniscus was larger than that of the medial meniscus. Conclusion Our finite element model provides a realistic three-dimensional model to evaluate the influence of different joint range of motion and rotating tibiofemoral joint stress distribution. The decreased displacement of the medial meniscus may explain the higher pressure on the knee components. These characteristics of the medial tibiofemoral joint indicate the potential biomechanical risk of knee degeneration.


2011 ◽  
Vol 422 ◽  
pp. 51-54 ◽  
Author(s):  
Jian Hua Zhang ◽  
Ling Yu Sun ◽  
Xiao Jun Zhang ◽  
Jia Peng Li

The oil-immersed transformer tank is an outside package component of the transformer body. The sealing quality and mechanical strength of the oil tank are affected by the deformation after loading. In this paper, the 3D finite element model of oil-immersed transformer tank is established. The oil-immersed transformer tank deformation is obtained by FEA under the condition of vacuuming. A series of experiments about the deformation of the oil-immersed transformer tank are carried out. Comparing experiment results with FEA results, FEA results are agrees well with the experiments’. It can save the time consumed on designing the oil tank, and has the directive function for the whole design.


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