scholarly journals The Verification of Human Lumbar Vertebrae and Intervertebral Disc Finite Element Models under Mechanical Forces

2021 ◽  
Vol 15 ◽  
pp. 1-10
Author(s):  
Mohankumar Palaniswamy ◽  
Anis Suhaila Shuib ◽  
Khai Ching Ng ◽  
Shajan Koshy
Keyword(s):  
Finite Element ◽  
Lumbar Vertebrae ◽  
Well Being ◽  
Intervertebral Discs ◽  
Finite Element Models ◽  
Geometrical Analysis ◽  
Total Deformation ◽  
Element Analysis ◽  
Significant Difference ◽  
Validation Procedure

Bone, being nonhomogeneous in nature need a complicated and time-consuming process to undergo computed simulation like finite element analysis. To overcome this hurdle, assuming a nonhomogeneous model as homogeneous could be a solution. The objective of this study is to focus on developing a homogeneous human lumbar finite element models and verify them under mechanical force by measuring disc stress, disc strain, disc deformation, total strain, and total deformation. Experimental and geometrical analysis were performed before verifying the lumbar model. To verify the models’ reliability, nonhomogeneous lumbar models were also developed. Five different static structural simulations were performed on four lumbar segments, and twenty parameters were measured. Numerically, out of twenty, eighteen parameters showed very less or no significant difference between homogeneous and nonhomogeneous models of the intervertebral discs and lumbar vertebrae. At the same time, proper caution to be provided while examining the results. With this validation procedure, researchers can process artifact images to get more information which enables them to contribute to the patient’s well-being.

A Finite Element Analysis of the General Rolling Contact Problem for a Viscoelastic Rubber Cylinder

1988 ◽  
Vol 16 (1) ◽  
pp. 18-43 ◽  
Author(s):  
J. T. Oden ◽  
T. L. Lin ◽  
J. M. Bass
Keyword(s):  
Finite Element ◽  
Variational Principles ◽  
Standing Waves ◽  
Rolling Contact ◽  
Finite Element Models ◽  
Viscoelastic Cylinder ◽  
Element Analysis ◽  
Elastic Rubber ◽  
Frictional Effects ◽  
Rough Foundation

Abstract Mathematical models of finite deformation of a rolling viscoelastic cylinder in contact with a rough foundation are developed in preparation for a general model for rolling tires. Variational principles and finite element models are derived. Numerical results are obtained for a variety of cases, including that of a pure elastic rubber cylinder, a viscoelastic cylinder, the development of standing waves, and frictional effects.

scholarly journals The biomechanical effect on the adjacent L4/L5 segment of S1 superior facet arthroplasty: a finite element analysis for the male spine

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zewen Shi ◽  
Lin Shi ◽  
Xianjun Chen ◽  
Jiangtao Liu ◽  
Haihao Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Range Of Motion ◽  
Facet Joint ◽  
Adjacent Segment ◽  
Finite Element Models ◽  
Level Of Evidence ◽  
Element Analysis ◽  
Flexion Extension ◽  
Biomechanical Effect ◽  
Lumbar Range Of Motion

Abstract Background The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty. Methods Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded. Results The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base. Conclusion In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base. Level of evidence Level IV

Accuracy of Failure Criteria Commonly Used for Ship Collision Simulations

2018 ◽  
Author(s):  
R. Villavicencio ◽  
Bin Liu ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Failure Criteria ◽  
Small Scale ◽  
Finite Element Models ◽  
Impact Loads ◽  
Large Scatter ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Ship Collision ◽  
Double Hull

The paper summarises observations of the fracture response of small-scale double hull specimens subjected to quasi-static impact loads by means of simulations of the respective experiments. The collision scenarios are used to evaluate the discretisation of the finite element models, and the energy-responses given by various failure criteria commonly selected for collision assessments. Nine double hull specimens are considered in the analysis so that to discuss the advantages and disadvantages of the different failure criterion selected for the comparison. Since a large scatter is observed from the numerical results, a discussion on the reliability of finite element analysis is also provided based on the present study and other research works found in the literature.

scholarly journals Finite Element Analysis of the Multilayered Honeycomb Composite Material Subjected to Impact Loading

2017 ◽  
Vol 54 (1) ◽  
pp. 180-179 ◽  
Author(s):  
Raul Cormos ◽  
Horia Petrescu ◽  
Anton Hadar ◽  
Gorge Mihail Adir ◽  
Horia Gheorghiu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Experimental Testing ◽  
Finite Element Models ◽  
The Finite Element Method ◽  
Low Velocity ◽  
Element Analysis ◽  
Element Simulation ◽  
Different Levels

The main purpose of this paper is the study the behavior of four multilayered composite material configurations subjected to different levels of low velocity impacts, in the linear elastc domain of the materials, using experimental testing and finite element simulation. The experimental results obtained after testing, are used to validate the finite element models of the four composite multilayered honeycomb structures, which makes possible the study, using only the finite element method, of these composite materials for a give application.

Nonlinear Finite Element Analysis of Moving Coil Loudspeaker Suspension

2006 ◽  
Author(s):  
Naveen Viswanatha ◽  
Mark Avis ◽  
Moji Moatamedi
Keyword(s):  
Finite Element Analysis ◽  
Computer Simulation ◽  
Finite Element ◽  
Physical Model ◽  
Cost Effective ◽  
Nonlinear Finite Element ◽  
Finite Element Models ◽  
Element Analysis ◽  
Sinusoidal Load ◽  
Geometric Effects

The surround and the spider of the loudspeaker suspension are modelled in ANSYS to carry out finite element analysis. The displacement dependent nonlinearities arising from the suspension are studied and the material and geometric effects leading to the nonlinearities are parameterised. The ANSYS models are simulated to be excited by a sinusoidal load and the results are evaluated by comparison with the results obtained by a physical model. The paper illustrates how practical models can be analysed using cost effective finite element models and also the extension of the models to experiment on various parameters, like changing the geometry for optimisation, by computer simulation.

Comparison of four methods to simulate swelling in poroelastic finite element models of intervertebral discs

2011 ◽  
Vol 4 (7) ◽  
pp. 1234-1241 ◽  
Author(s):  
Fabio Galbusera ◽  
Hendrik Schmidt ◽  
Jérôme Noailly ◽  
Andrea Malandrino ◽  
Damien Lacroix ◽  
...  
Keyword(s):  
Finite Element ◽  
Intervertebral Discs ◽  
Finite Element Models

scholarly journals Prediction of Vehicle Crashworthiness Parameters Using Piecewise Lumped Parameters and Finite Element Models

Designs ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 43 ◽  
Author(s):  
Bernard B. Munyazikwiye ◽  
Dmitry Vysochinskiy ◽  
Mikhail Khadyko ◽  
Kjell G. Robbersmyr
Keyword(s):  
Finite Element ◽  
Severity Index ◽  
Finite Element Models ◽  
Element Analysis ◽  
Computational Costs ◽  
Nonlinear Springs ◽  
Crash Testing ◽  
Lumped Parameters ◽  
Crashworthiness Analysis ◽  
Vehicle Crashworthiness

Estimating the vehicle crashworthiness experimentally is expensive and time-consuming. For these reasons, different modelling approaches are utilised to predict the vehicle behaviour and reduce the need for full-scale crash testing. The earlier numerical methods used for vehicle crashworthiness analysis were based on the use of lumped parameters models (LPM), a combination of masses and nonlinear springs interconnected in various configurations. Nowadays, the explicit nonlinear finite element analysis (FEA) is probably the most widely recognised modelling technique. Although informative, finite element models (FEM) of vehicle crash are expensive both in terms of man-hours put into assembling the model and related computational costs. A simpler analytical tool for preliminary analysis of vehicle crashworthiness could greatly assist the modelling and save time. In this paper, the authors investigate whether a simple piecewise LPM can serve as such a tool. The model is first calibrated at an impact velocity of 56 km/h. After the calibration, the LPM is applied to a range of velocities (40, 48, 64 and 72 km/h) and the crashworthiness parameters such as the acceleration severity index (ASI) and the maximum dynamic crush are calculated. The predictions for crashworthiness parameters from the LPM are then compared with the same predictions from the FEA.

Computer Aided Modeling and Finite Element Analysis of Human Elbow

2016 ◽  
Vol 5 (1) ◽  
pp. 31-38
Author(s):  
Arpan Gupta ◽  
O.P. Singh
Keyword(s):  
Finite Element ◽  
Research Work ◽  
Well Being ◽  
Computer Aided Engineering ◽  
Weight Lifting ◽  
Patient Specific ◽  
Element Analysis ◽  
Detailed Model ◽  
Computer Aided ◽  
Safe Load

Finite element modeling (FEM) plays a significant role in the design of various devices in the engineering field of automotive, aerospace, defense etc. In the recent past, FEM is assisting engineers and healthcare professional in analyzing and designing various medical devices with advanced functionality. Computer aided engineering can predict failure circumstances, which can be avoided for the health and well-being of people. In this research work, computer aided engineering analysis of human elbow is presented beginning with modeling of human elbow from medical image data, and predicting the stresses in elbow during carrying heavy loads. The analysis is performed by using finite element method. The results predict the stress level and displacement in the human bone during heavy weight lifting. Thus, it can be used to predict the safe load that a particular person can carry without bone injury. The present analysis focused on a particular model of bone for a particular individual. However, safe load can be determined for various age groups by generating more detailed model including tendons, ligaments and by using patient specific material properties.

Experimental Investigation and Elastic-Plastic Analysis on Connection Strength of Zirconium Tube-Tubesheet Joints

2008 ◽  
Vol 44-46 ◽  
pp. 529-536
Author(s):  
Biao Yuan ◽  
Y.Z. Wang ◽  
X. Ma ◽  
Yang Yan Zheng ◽  
Shan Tung Tu
Keyword(s):  
Finite Element ◽  
Heat Exchanger ◽  
Element Model ◽  
Connection Strength ◽  
Element Analysis ◽  
Petrochemical Process ◽  
Expansion Joints ◽  
Pull Out ◽  
Significant Difference ◽  
Zirconium Tube

Zirconium tube is widely used in heat exchanger equipments in petrochemical process for significant corrosion resistance. The connection joint of tube-tubesheet is the weakest parts in a heat exchanger. The experiment and numerical analysis of different materials (zirconium tubes, titanium tubes and 16MnR tubesheets, 316L tubesheet) joints were performed in this paper. The expansion joints specimens were prepared at the pressure ranging from 28MPa to 38MPa. And pulling out test was performed from 20°C to 300°C. The finite element model of tube-tubesheet joint was established. The effect of expansion pressure, temperature and groove on the pulling out strength of joints was analyzed. Both the experiments and the finite element analysis show that the pull-out strength increases with the increasing expansion pressures. Working temperature also has a great effect on the connection strength of tube-to-tubesheet joints, especially for the zirconium and 316L joints, which have the most significant difference of thermal expansion coefficient between tube and tubesheet. The residual contacting pressure on the contact surface between tubes and the tubesheet is not uniformly distributed and two tightness bands are found near the surfaces of the tubesheet or at the two brinks of the groove on the tubesheet hole. Compared with the ungrooved joint, the residual contacting pressure on the tightness bands for the grooved joint is much higher, indicating a grooved joint has better tightness.

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