On the Influence of Friction in the Calculation of Conical Disk Springs

1999 ◽  
Vol 121 (4) ◽  
pp. 622-627 ◽  
Author(s):  
G. Curti ◽  
R. Montanini
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Analytical Solution ◽  
Maximum Error ◽  
Accurate Estimate ◽  
Analytical Prediction ◽  
Numerical Examples ◽  
Finite Element Calculations ◽  
New Formulation ◽  
Good Agreement

An analytical solution is proposed by the authors in order to take into account the effects of friction in the calculation of conical disk springs. The new formulation allows a more accurate estimate of the load corresponding to a given displacement, but it implies the knowledge of the friction coefficient f between the spring and the supporting surfaces. The reported numerical examples show that, disregarding friction effects, the maximum error committed in the evaluation of the load is in the range 2–5%, with f = 0.14 (average friction coefficient value determined experimentally on commercial conical disk springs with different geometry). Comparison with both experimental and finite element calculations show a very good agreement of the analytical prediction.

Analytical Solution of Sidewise Buckling of Two-Hinged Circular Arch under Concentrated Force

2013 ◽  
Vol 676 ◽  
pp. 170-174
Author(s):  
Ju Tao Kuang ◽  
Ai Rong Liu ◽  
Qi Ca Yu ◽  
Jiang Dong Deng
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Lateral Displacement ◽  
Displacement Function ◽  
Buckling Load ◽  
The Finite Element Method ◽  
Concentrated Force ◽  
Critical Buckling Load ◽  
Circular Arch ◽  
Good Agreement

By the setting torsional and lateral displacement function of sidewise buckling of two-hinged circular arch under concentrated force, the single-arch structure's bending, torsional deformation and external force potential can be constructed. An analytical solution for the lateral critical buckling load of two-hinged arch is first deduced by using the energy method; the results are also compared and analyzed by the finite element method. The results show that the analytical solution of single arch’s lateral critical buckling load is in good agreement with the finite element numerical solution, and the validity of the formula is proven.

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.

scholarly journals Modelling particle movement in conical guide of seeder pneumatic pipe

2020 ◽  
Vol 175 ◽  
pp. 12019
Author(s):  
Vladimir Zaitsev ◽  
Artem Kravtsov ◽  
Vladimir Konovalovi
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Air Flow ◽  
Force Analysis ◽  
Particle Movement ◽  
Air Velocity ◽  
Finite Element Calculations ◽  
Calculation Results ◽  
Case Part ◽  
Good Agreement

In the course of the study, methods for ensuring the centeringof particlesofbulkmaterialintheairflowmovinginthepneumaticductofthe seeder were investigated. To solve this problem, it is proposed to use a conical confusor. The aim of the study was to obtain the functional dependences of the movement of particles in a conical airflow guide (confusor) for the conditions of transportation of the sown particles on the basis of force analysis and to identify the nature of the movement of the sownparticlesinataperingairflow.Duringthestudy,todescribethemotion of particles in a vertical tapering pipe, a system of expressions was substantiated. The developed mathematical model of particle motion in a conical air flow, implemented in the MathCAD mathematical package, allowscalculatingboththeparticletrajectoryandthevelocityparametersof the air flow and the particles to be sown. The digital calculation results in the MathCAD program are in good agreement with the finite element calculations. The magnitude of the error in air velocity is less than 1%. The differences in the velocities of the transported particles in the calculation options do not exceed 7%. The installation of a conical guide helps tofocus the flow of particles in the central part of the narrowed air line. In this case, part of the particles in the central part of the guide will retain the initial longitudinaltrajectory.Theangleattheapexoftheconeandtheparameters of the particles affect the speed and angle of the tangent contact of the particle with theguide.

An Integral Equation Method for Predicting Acoustic Emission within Enclosures

1985 ◽  
Vol 199 (2) ◽  
pp. 133-137 ◽  
Author(s):  
D T I Francis ◽  
M M Sadek
Keyword(s):  
Integral Equation ◽  
Finite Element ◽  
Acoustic Emission ◽  
Analytical Solution ◽  
Numerical Solution ◽  
Finite Element Methods ◽  
Exact Analytical Solution ◽  
Integral Equation Method ◽  
Absorption Characteristics ◽  
Good Agreement

A method is presented for calculating the acoustic emission of a vibrating body within an enclosure whose surface has known absorption characteristics. It is based on a numerical solution of the Helmholtz integral equation. Solutions are given for the case of a pulsating sphere within a sphere, and good agreement with the exact analytical solution is reported. The method is of value for small and medium scale problems at lower frequencies, where traditional techniques are less reliable. It is also potentially less demanding computationally than finite element methods.

A study on finite element analysis for simplification of curvature extrusion method

2018 ◽  
Vol 32 (19) ◽  
pp. 1840043
Author(s):  
J. O. Yu ◽  
Y. H. Kim ◽  
Nagamachi Takuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Extrusion Process ◽  
Experimental Results ◽  
Element Analysis ◽  
Extrusion Method ◽  
Good Agreement

To eliminate the complexity of curvature extrusion process, a new extrusion method was proposed. In this study, a finite element analysis for curvature extrusion was studied to commercialize this extrusion method that creates curvature in a tilting method. When simulating an extrusion process, it is important to fix the appropriate friction coefficient and fillet value to avoid peel-out problems such that the finite element disappears. Therefore, the actual extrusion results and the simulated results were compared to find conditions that the element would not disappear. There was a good agreement between the simulation and experimental results when the coefficient friction was 0.4 and the fillet was 0.4 mm.

Analytical Prediction of Tubular Light-Pipe Performance Under Arbitrary Sky Conditions

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Jaromír Petržala ◽  
Ladislav Kómar
Keyword(s):  
Analytical Solution ◽  
Light Guide ◽  
Analytical Prediction ◽  
Optical Efficiency ◽  
Deep Interior ◽  
Wide Range ◽  
The Mean ◽  
Light Guides ◽  
Sky Conditions ◽  
Good Agreement

The tubular light guides are devices allowing deliverance of solar light into deep interior rooms, offices, or underground spaces. Due to considerable costs of such systems, the reasonable assessment of their lighting performance is desirable. To predict accurately their efficiency, precise numerical computations have to be performed. Such computations may be strongly time consuming, mainly when mass calculations are required as it is in case of the so-called climate-based daylight modeling. This paper presents an analytical solution to the optical efficiency of cylindrical straight pipes that is applicable over a wide range of pipe’s parameters and under arbitrary sky luminance conditions. The proposed method gives results in good agreement with ray-tracing numerical simulations—the mean absolute percentage errors are less than 3%—but unlike them, the calculations are much faster. Therefore, it appears to be convenient for daylight modeling, which takes into account utilization of tubular light guide systems in buildings.

New Insight Into Viscoelastic Finite Element Modeling of Time-Dependent Material Creep Problems Using Spherical Hankel Element Framework

2018 ◽  
Vol 10 (08) ◽  
pp. 1850085 ◽  
Author(s):  
M. Bahrampour ◽  
S. Hamzeh Javaran ◽  
S. Shojaee
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Modeling ◽  
Degrees Of Freedom ◽  
Shape Functions ◽  
Element Modeling ◽  
Hankel Functions ◽  
Material Creep ◽  
New Formulation ◽  
Insight Into

In this study, a new formulation of finite element method (FEM) has been extracted to analyze 2D viscoelastic problems. As there has not been enough accuracy and not sufficient literature in classical finite element modeling of viscoelastic problems, using a new set of shape functions founded on radial basis functions (RBFs) is recommended. Applying these new, RBF-based shape functions instead of the classical Lagrangian ones, results in subtler answers and conducts a reconsideration over the usual numerical method. Hankel functions are chosen, enriched and summed up with polynomial terms. Therefore, they satisfy not only polynomial terms, but also the first- and second-order Bessel functions simultaneously; which, in the case of classic shape functions, happens only for the polynomial function field. This method illustrates an approach with faster convergence rate and better robustness in different manners. Hence, it is less time-consuming and economical. Finally, various numerical examples are provided for the comparison of analytical solution, classic FEM and Hankel-based FEM, which show the much better agreement of the proposed method with analytical solution in comparison to classic FEM. Also, the number of nodes and degrees of freedom are reduced noticeably while maintaining accuracy in the interpolation of the adopted procedure.

An Analytical Solution for Stress and Displacement in Casing-Cement Combined Cylinder under Non-Uniform Loading

2011 ◽  
Vol 291-294 ◽  
pp. 2133-2138 ◽  
Author(s):  
Mu Hui Fan ◽  
Yong Shu Jiao ◽  
Zong Xi Cai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Solution ◽  
Computer Program ◽  
Theory Of Elasticity ◽  
Composite Cylinder ◽  
The Finite Element Method ◽  
Uniform Loading ◽  
Cement Sheath ◽  
Good Agreement

Based on the theory of elasticity and taken the casing-cement sheath as a totally contacted composite cylinder subjected to arbitrarily distributed loading on inner and outer surfaces, an analytical solution in Fourier serial form was obtained for stresses and displacements. A computer program was developed to evaluate the stress and displacement in the combined cylinder. The results are in good agreement with those from the finite element method (FEM). With these solutions we can investigate the interaction between casing and the cement sheath. This is of importance in improving the design of casing.

scholarly journals Theoretical Bending Collapse of Hat-Section Tubes

2018 ◽  
Vol 7 (4.26) ◽  
pp. 153
Author(s):  
Hafizan Hashim ◽  
Hanita Hashim ◽  
Arif Affendi Jamal ◽  
M. A.M. Jusoh
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Plastic Region ◽  
Tubular Structures ◽  
Pure Bending ◽  
Analysis Technique ◽  
Collapse Model ◽  
The Moment ◽  
Relationship Of ◽  
Good Agreement

This paper presents an attempt to modify an existing theoretical model to predict the bending collapse response of hat-section tubular structures. The analytical collapse model was based on Kim and Reid. Additional hinge lines created during deformation of the tube were examined and integrated with existing model to forming a modified analytical solution. Variation of the hinge moments were solved using limit analysis technique. Procedure for developing the finite element (FE) models of tube specimens was also presented. Moment-rotation characteristics from pure bending simulation were compared with analytical model and good agreement was achieved. The average of differences between simulation and calculation were found to be <5% within plastic region. In conclusion, the modified analytical solution has adequate capability to predict the moment-rotation relationship of hat-section tubes subject to pure bending.. 

A Study of Jones’ Equation for Buckling of Laminated Composite Cylinders Under External Hydrostatic Pressure

1993 ◽  
Vol 37 (03) ◽  
pp. 239-252
Author(s):  
Thomas Perry ◽  
Zan Miller
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Materials ◽  
Hydrostatic Pressure ◽  
Analytical Solution ◽  
Laminated Composite ◽  
External Hydrostatic Pressure ◽  
Element Analysis ◽  
Composite Cylinders ◽  
Good Agreement

A classical solution derived by Jones (1968) is used to evaluate the buckling performance of unstiffened generally orthotropic and quasi-isotropic laminated Graphite/Epoxy (GREP) composite cylinders subjected to external hydrostatic pressure. The results of the analysis are compared to finite-element analysis results. Hydrostatic testing to failure of several 12-ply T300/5208 GREP cylinders demonstrated that the classical buckling solution is quite accurate. The finite-element results showed good agreement with both Jones' solution and test data, with several notable exceptions. Evaluation of strain gage data via Southwell's (1932) method indicates that the test cylinders were fabricated very nearly true. A postiori buckling predictions using Southwell plots all compared quite favorably with the Jones' equation predictions. This work demonstrates that a relatively simple analytical solution can reliably evaluate the performance of composite materials in pressure hull applications.

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