Unreinforced Flat Oval Duct Deformation Testing and Modeling

2020 ◽  
Author(s):  
Avinash Paruchuri ◽  
Jane Liu ◽  
Stephen Idem
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Galvanized Steel ◽  
Finite Element Models ◽  
Element Analysis ◽  
Linear Finite Element ◽  
Duct Wall ◽  
Model Predictions ◽  
Average Wall Thickness ◽  
Corrugated Duct

Abstract Unreinforced 12 in. × 23 in. (305 mm × 584 mm) galvanized steel flat oval ducts were tested to measure deformations when internal static gauge pressures were applied. The experiments were performed on spiral seam non-corrugated duct. Finite element models with discrete ring seams and an average wall thickness approach were utilized to represent the continuous spiral seam, and therein predict duct deflections at prescribed locations along the duct wall. Predicted deflections from the finite element models were tabulated and compared to experimental data. Satisfactory agreement between model predictions and test data were obtained from a non-linear finite element analysis that employed a simplified average wall thickness to characterize the spiral seam and duct wall. It is straightforward to implement the average wall thickness methodology in finite element modeling of duct deformation.

Pre-overloading to Extend Fatigue Life of Cast Clasps

2007 ◽  
Vol 86 (9) ◽  
pp. 868-872 ◽  
Author(s):  
A. Mahmoud
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Permanent Deformation ◽  
Maximum Tensile Stress ◽  
Finite Element Models ◽  
Gold Alloys ◽  
Element Analysis ◽  
Linear Finite Element ◽  
Type Iv ◽  
Cast Condition

Permanent deformation in bending is associated with the development of residual stresses. The objective of this study was to characterize those residual stresses and test whether they can be manipulated to extend the fatigue lives of cast clasps. Simulations with validated non-linear finite element models were used to characterize the residual stresses in clasps cast from Ti-6Al-7Nb, Co-Cr, and Type IV gold alloys. In addition, two groups of as-cast and pre-overloaded (subjected to a load that produced 20 μm of permanent deformation) Ti-6Al-7Nb clasps (10 specimens each) were subjected to cyclic 0.5-mm deflections at 5 Hz until fatigue. Pre-overloaded specimens demonstrated significantly longer fatigue lives (32,200 ± 17,300 cycles) than did those tested in the as-cast condition (17,900 ± 7600 cycles), consistent with the maximum tensile stress values revealed by finite element analysis.

Guidelines for FEA Modeling of Cylinder-to-Cylinder Intersection

2004 ◽  
Author(s):  
Liping Xue ◽  
G. E. O. Widera
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Finite Element Models ◽  
Element Analysis ◽  
Fea Model ◽  
Fea Modeling ◽  
Out Of Plane

The purpose of this paper is to develop a definitive set of guidelines for carrying out finite element analysis (FEA) modeling of cylinder-to-cylinder intersections. By studying the stresses in the neighborhood of such intersections subjected to internal pressure and external moments (in-plane and out-of-plane moments) resulting from the use of various finite element models, the effects of number of elements along the nozzle circumference, number of elements through the wall thickness and element sizes in the direction perpendicular to nozzle circumference are investigated. Finally, general guidelines are proposed for setting up a FEA model of cylinder-to-cylinder intersections.

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

Specimen positioning effect on microshear test: Non-linear finite element analysis

2012 ◽  
Vol 28 ◽  
pp. e15-e16
Author(s):  
L.H.A. Raposo ◽  
L.C.M. Dantas ◽  
T.A. Xavier ◽  
A.G. Pereira ◽  
A. Versluis ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Linear Finite Element ◽  
Non Linear

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.

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