Nonlinear stress analysis of muskeg via finite element

1991 ◽  
Vol 28 (4) ◽  
pp. 613-629 ◽  
Author(s):  
R. N. Yong ◽  
A. M. O. Mohamed ◽  
R. G. Tali
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Key Words ◽  
Analytical Model ◽  
Constitutive Behavior ◽  
Experimental Program ◽  
Nonlinear Stress ◽  
Stress And Deformation ◽  
Element Technique ◽  
Good Agreement

The purpose of this paper is to provide a rational analytical means for predicting the performance of a muskeg deposit under loading. The analytical model employs the finite-element technique, which is extended to take into consideration the unusual constitutive behavior of the fibrous organic materials as well as the tension cut developing in these materials. The solution obtained using this model provides detailed stress and deformation fields within the loaded muskeg deposit. The applicability of the proposed analytical model is verified by conducting an appropriate experimental program. The results obtained from the model are found to be in good agreement with the experimental data. Key words: muskeg, loading, modelling, anisotropic, finite element, tension, compression.

Modeling Procedures for the Stress Analysis of Flexible Pipe Cross Sections

1993 ◽  
Vol 115 (1) ◽  
pp. 46-51 ◽  
Author(s):  
A. M. Harte ◽  
J. F. McNamara
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Cross Sections ◽  
Three Dimensional ◽  
Flexible Pipe ◽  
Discrete Reinforcement ◽  
Tube Type ◽  
Element Technique ◽  
Main Deformation ◽  
Good Agreement

Thick tube theory is incorporated into an existing analytical model for the three-dimensional analysis of bonded flexible pipe cross sections under offshore loading conditions. The original model considers material layers as isotropic/orthotopic thin tubes, and layers of helically wound reinforcing cables are modeled separately. The improvement in the results obtained with the incorporation of the new thick tube layer is demonstrated for a flexible pipe with D/t = 10. The finite element technique has also been used to model this type of pipe structure. Pipe sections are discretized using axisymmetric elements for the tube-type layers and special discrete reinforcement elements for the helical cables. A particular example of a three-layer doubly reinforced pipe section under internal pressure is studied. Good agreement is found between analytical model and finite element results for all the main deformation and stress quantities including cable stresses.

scholarly journals Development of a new test rig for the analysis of hydrodynamic bearings for rotors of microGT

2019 ◽  
Vol 113 ◽  
pp. 03002
Author(s):  
Carlo Alberto Niccolini Marmont Du Haut Champ ◽  
Fabrizio Stefani ◽  
Paolo Silvestri
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Gas Turbines ◽  
Dynamic Interaction ◽  
Journal Bearings ◽  
Radial Clearance ◽  
Test Rig ◽  
Small Clearance ◽  
Stiffness And Damping ◽  
Good Agreement

The aim of the present work is to design a test rig suited to investigate the dynamic interaction between rotor and hydrodynamic journal bearings in micro gas turbines (microGT), i.e. with reference to small bearings (diameter in the order of ten millimeters). Particularly, the device is capable of measuring the journal location. Therefore, the journal motion due to rotor vibrations can be displayed, in order to assess performance as well as stiffness and damping of the bearings. The new test rig is based on Bently Nevada Rotor Kit (RK), but substantial modifications are carried out. Indeed, the relative radial clearance of the original RK bearings is about 2/100, while it is in the order of 1/1000 in industrial bearings. Therefore, the same RK bearings are employed in the new test rig, but a new shaft has been designed in order to reduce the original clearance. The new shaft enables us to study the bearing behaviour for different clearances, as it is equipped with interchangeable journals. The experimental data yielded by the new test rig are compared with numerical results. These are obtained by means of a suitable finite element (FEM) code developed by our research group. It allows the Thermo Elasto-HydroDynamic (TEHD) analysis of the bearing in static and dynamic conditions. In the present paper, bearing static performances are analysed in order to assess the reliability of the journal location predictions by comparing numerical and experimental results. Such comparisons are presented for both large and small clearance bearings of original and modified RK, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance equal to 8/1000). Nevertheless, rotor alignment is quite difficult with small clearance bearings and a completely new test rig is designed for future experiments.

scholarly journals Response of a Warped Flexible Rotor with a Fluid Bearing

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Jim Meagher ◽  
Xi Wu ◽  
Chris Lencioni
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Equation Of Motion ◽  
Diagnostic Information ◽  
Flexible Rotor ◽  
Vibration Data ◽  
Rotor Model ◽  
Good Agreement

A two-complex-degrees-of-freedom model is developed and compared to experimental data for various amounts of rotor bow and its orientation to mass imbalance of the rotor. The equation of motion is developed by adding constant forces that rotate with the rotor to a Bently-Muszynska two-mode isotropic rotor model with a plane journal bearing. Diagnostic information discernable from probes at the bearing is explored and compared to midspan response, where previous research has concentrated. The model presented also extends earlier work by representing the effect of a nonrigid bearing. Good agreement between the analytical model and experiment demonstrates that the analysis presented can be useful to diagnose and balance residual shaft bow from probes located at the bearings, where vibration data are typically more available than midspan probes.

Evaluation of Finite Element Calculations in a Cracked Cylinder Under Internal Pressure by Speckle Photography

1983 ◽  
Vol 50 (4a) ◽  
pp. 896-897 ◽  
Author(s):  
G. H. Kaufmann ◽  
A. M. Lopergolo ◽  
S. Idelsohn
Keyword(s):  
Experimental Data ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Mode I ◽  
Speckle Photography ◽  
Crack Line ◽  
Finite Element Calculations ◽  
Pressurized Cylinder ◽  
Good Agreement

The usefulness of using the speckle photography technique in fracture mechanics to check numerical calculations is demonstrated for an internally pressurized cylinder with a surface flaw. A pointwise technique was utilized to measure the opening displacements along the crack line and the Mode I stress-intensity factor was determined by extrapolating these results to the crack tip. Finite element calculations were performed to be compared with experimental data and good agreement was obtained.

The Finite Element Analysis of New Forged Coupler Knuckle

2013 ◽  
Vol 367 ◽  
pp. 122-125
Author(s):  
Guang Xin Wang ◽  
Xiang Shun Bu ◽  
Lin Jie Li ◽  
Li Li Zhu
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Direct Relationship ◽  
Element Analysis ◽  
Compression Load ◽  
The Finite Element Analysis ◽  
Simulation Results ◽  
Element Technique ◽  
Working Situation ◽  
Made In

As one of the most important load-bearing parts, coupler knuckle has a direct relationship with the safety in operation and reliability of the freight trains. A new forged coupler knuckle is made in order to meet the challenge to export ore train to Australia. Using the finite element technique, the stress characteristics of forged coupler knuckle under 1225kN load in tension and 1500kN compression load are evaluated. Simplify the load and boundary condition depend on the real working situation, the numerical simulation results coincide with experimental data.

A reaction-force-validated soccer ball finite element model

2016 ◽  
Vol 231 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Zahari Taha ◽  
Mohd Hasnun Arif Hassan
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Reaction Force ◽  
Element Model ◽  
Optimal Number ◽  
Ball Impact ◽  
Soccer Ball ◽  
Mesh Density ◽  
Good Agreement

The soccer ball is one of the important pieces of equipment in the game of soccer. It undergoes various forms of impact during the game. In order to numerically investigate the occasions of ball impact such as soccer heading, a validated finite element model of a soccer ball is required. Therefore, a model was developed incorporating material properties obtained from literature. To ensure the accuracy of the model, it was validated against an established soccer ball model and experimental data of the coefficient of restitution, contact time, longitudinal deformation and reaction force. In addition, a parametric study of the mesh density was also performed to determine the optimal number of elements. The developed soccer ball model was found to be in a good agreement with the literature and experimental data. This suggests that, the soccer ball model is capable of replicating the impacts of interest. This article details the development of the model and the validation processes.

Finite Element Modeling of Annular-Like Acoustic Cavities

1985 ◽  
Vol 107 (1) ◽  
pp. 81-85
Author(s):  
Chaw-Hua Kung ◽  
Rajendra Singh
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Pressure Oscillation ◽  
Transient Heat Conduction ◽  
Natural Frequencies And Modes ◽  
Acoustic Cavities ◽  
Eigen Solutions ◽  
Element Technique ◽  
Good Agreement

A finite element technique has been developed to find natural frequencies and modes of undamped three-dimensional acoustic cavities. This method utilizes the analogy between a special form of the discretized transient heat conduction equations and discretized equations of acoustic pressure oscillation. The proposed technique is verified by applying it to several cavities of known theoretical eigen-solutions. Computed results for an acoustic ring, an acoustic disk, and a pure annular cavity match extremely well with exact solutions. In addition, the condensation scheme is investigated and guidelines of selecting acoustic master nodes appropriately are also discussed in the paper. Using the validated finite element method along with suitable condensation, the eigenvalue problem of an annular-like cavity is solved. Since the exact solution for this case is not possible, finite element computations for natural frequencies and modes are compared with the measured results obtained using an acoustic modal analysis experimental technique; again very good agreement has been found.

Stability of Ring-Stiffened Tubular Members Under External Pressure

1995 ◽  
Vol 117 (2) ◽  
pp. 150-155 ◽  
Author(s):  
S. A. Karamanos ◽  
J. L. Tassoulas
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Stability Analysis ◽  
External Pressure ◽  
Nonlinear Finite Element ◽  
Steel Tubes ◽  
Deformation Plasticity ◽  
The Stability ◽  
Element Technique ◽  
Stiffened Steel

This paper presents results of a rigorous nonlinear finite element technique for the stability analysis of ring-stiffened steel tubes under external pressure. Large deformation, plasticity, as well as residual stresses and imperfections, are taken into account. Both internal and external stiffeners are simulated. A study of various parameters which affect pressure capacity is summarized, along with a comparison with available experimental data.

Experimental Program for Investigating the Influence of Cladding Defects on Burst Pressure

2006 ◽  
Author(s):  
Shengjun (Sean) Yin ◽  
B. Richard Bass ◽  
Wallace J. McAfee ◽  
Paul T. Williams
Keyword(s):  
Finite Element ◽  
National Laboratory ◽  
Maximum Load ◽  
Plastic Instability ◽  
Experimental Program ◽  
Finite Element Models ◽  
Ductile Tearing ◽  
Oak Ridge ◽  
Clad Layer ◽  
Good Agreement

An experimental program was conducted by the Heavy-Section Steel Technology Program at the Oak Ridge National Laboratory (ORNL) to evaluate the structural significance of defects found in the unbacked cladding of the Davis-Besse vessel head. ORNL conducted total 13 clad burst tests with unflawed/flawed specimens. Failure pressure data from those tests indicated a high degree of repeatability for the tests performed in the clad burst program. Unflawed clad burst specimens failed around the full perimeter of the disk from plastic instability; an analytical model for plastic collapse was shown to adequately predict those results. The flawed specimens tested in the program failed by ductile tearing of the notch defect through the clad layer. Analytical interpretations that utilized 3-D finite element models of the clad burst specimens were performed for all tests. Fractographic studies were performed on failed defects in the flawed burst specimens to verify the ductile mode of failure. Comparisons of computed results from 3-D finite element models with measured gage displacement data (i.e., center-point deflection and CMOD) indicated reasonably good agreement up to the region of instability. For tests instrumented with the CMOD gage, good agreement between calculated and measured CMOD data up to the onset of instability implies that ductile tearing initiated near the maximum load and (with a small increase in load) rapidly progressed through the clad layer to produce failure of the specimen.

scholarly journals Modelling the Thermal Energy Storage of Cementitious Mortars Made with PCM-Recycled Brick Aggregates

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1064 ◽  
Author(s):  
Christoph Mankel ◽  
Antonio Caggiano ◽  
Andreas König ◽  
Diego Said Schicchi ◽  
Mona Nazari Sam ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Change Materials ◽  
Numerical Approach ◽  
Numerical Results ◽  
Experimental Program ◽  
Heat Accumulation ◽  
Modelling Method ◽  
Further Development ◽  
Capacity Method ◽  
Good Agreement

This paper reports a numerical approach for modelling the thermal behavior and heat accumulation/liberation of sustainable cementitious composites made with Recycled Brick Aggregates (RBAs) employed as carriers for Phase-Change Materials (PCMs). In the framework of the further development of the fixed grid modelling method, classically employed for solving the well-known Stefan problem, an enthalpy-based approach and an apparent calorific capacity method have been proposed and validated. More specifically, the results of an experimental program, following an advanced incorporation and immobilization technique, developed at the Institut für Werkstoffe im Bauwesen for investigating the thermal responses of various combinations of PCM-RBAs, have been considered as the benchmark to calibrate/validate the numerical results. Promising numerical results have been obtained, and temperature simulations showed good agreement with the experimental data of the analyzed mixtures.

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