Use of measured imperfections to predict the buckling of axially loaded cylindrical shells

1983 ◽  
Vol 10 (4) ◽  
pp. 662-669 ◽  
Author(s):  
R. B. Pinkney ◽  
M. J. Stephens ◽  
D. W. Murray ◽  
G. L. Kulak
Keyword(s):  
Finite Element ◽  
Structural Engineering ◽  
Plastic Material ◽  
Cylindrical Shells ◽  
Flow Rule ◽  
Initial Imperfections ◽  
Perfectly Plastic ◽  
Axially Loaded ◽  
Elastic Perfectly Plastic ◽  
Element Technique

Analyses to predict inelastic buckling of axially loaded thin cylindrical shells are carried out using the finite element technique. The analyses use a bilinear elastic–perfectly plastic material response based upon the associated flow rule of plasticity. Nonlinear geometric effects, combined with initial imperfections, produce load-deflection curves with descending branches for which the limit points are imperfection sensitive.Results from these analyses are compared with two tests of axially loaded cylinders fabricated from 10-gauge (3.4-mm) and 5-mm plate and approximately 1525 mm in diameter. These tests were carried out in the Structural Engineering Laboratory at the University of Alberta. A rational technique for using measured imperfections to obtain effective initial imperfections for use in the analyses is investigated, and is shown to result in accurate predictions of ultimate load. Keywords: shell, cylinder, buckling, plastic, imperfection, axial load, finite element, nonlinear analysis.

Elasto-Plastic Coupled Temperature-Displacement Finite Element Analysis of Two-Dimensional Rolling-Sliding Contact With a Translating Heat Source

1991 ◽  
Vol 113 (1) ◽  
pp. 93-101 ◽  
Author(s):  
S. M. Kulkarni ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Finite Element ◽  
Half Space ◽  
Plastic Material ◽  
Element Model ◽  
Rolling Contact ◽  
Two Dimensional ◽  
Element Analysis ◽  
Element Mesh ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

The present paper, describes a transient translating elasto-plastic thermo-mechanical finite element model to study 2-D frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a non-uniform thermo-mechanical distribution across the surface of an elasto-plastic half space. The half space is represented by a two dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermo-physical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on 1) the temperature gradients and 2) the magnitudes of the normal and tangential tractions.

A limit load solution for a thick-walled cylinder with a fully circumferential crack under axial tension

2009 ◽  
Vol 44 (6) ◽  
pp. 407-416 ◽  
Author(s):  
P J Budden ◽  
Y Lei
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Yield Criterion ◽  
Limit Load ◽  
Cylinder Wall ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Von Mises ◽  
Inside Radius ◽  
Walled Cylinder

Limit loads for a thick-walled cylinder with an internal or external fully circumferential surface crack under pure axial load are derived on the basis of the von Mises yield criterion. The solutions reproduce the existing thin-walled solution when the ratio between the cylinder wall thickness and the inside radius tends to zero. The solutions are compared with published finite element limit load results for an elastic–perfectly plastic material. The comparison shows that the theoretical solutions are conservative and very close to the finite element data.

A Finite Element Based Study on the Elastic-Plastic Transition Behavior in a Hemisphere in Contact With a Rigid Flat

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
S. Shankar ◽  
M. M. Mayuram
Keyword(s):  
Finite Element ◽  
Contact Area ◽  
Plastic Material ◽  
Plastic Region ◽  
Real Contact Area ◽  
Real Contact ◽  
Perfectly Plastic ◽  
The Difference ◽  
Elastic Perfectly Plastic ◽  
Green Model

An axisymmetrical hemispherical asperity in contact with a rigid flat is modeled for an elastic perfectly plastic material. The present analysis extends the work (sphere in contact with a flat plate) of Kogut–Etsion Model and Jackson–Green Model and addresses some aspects uncovered in the above models. This paper shows the critical values in the dimensionless interference ratios (ω∕ωc) for the evolution of the elastic core and the plastic region within the asperity for different Y∕E ratios. The present analysis also covers higher interference ratios, and the results are applied to show the difference in the calculation of real contact area for the entire surface with other existing models. The statistical model developed to calculate the real contact area and the contact load for the entire surfaces based on the finite element method (FEM) single asperity model with the elastic perfectly plastic assumption depends on the Y∕E ratio of the material.

Approximate Elastic-Plastic Analysis of Intersecting Equal Diameter Cylindrical Shells

1981 ◽  
Vol 103 (1) ◽  
pp. 111-115
Author(s):  
D. P. Updike
Keyword(s):  
Plastic Material ◽  
Cylindrical Shells ◽  
Yield Condition ◽  
Pressure Vessels ◽  
Ductile Materials ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Plastic Analysis ◽  
Elastic Perfectly Plastic ◽  
Von Mises

Design of connections of pipes and pressure vessels on the basis of a calculated maximum elastic stress often proves to be too conservative in the case of ductile materials. Elastic-plastic analysis by the finite element method proves to be too costly. This paper presents an alternative method which reduces the calculations to those of a rotationally symmetric shell subjected to axisymmetric loading. Using this approach approximate elastic-plastic deformations on the meridian passing through the crotch of a tee branch connection of cylindrical shells of equal diameter and thickness are determined. The method is limited to cases of the normal intersection of very thin shells of identical diameter, thickness, and material and to internal pressure loading. Numerical results for the intersection of two shells of R/t equal to 100 are given for an elastic-perfectly plastic material satisfying the von Mises yield condition.

Finite Element Based Unloading of an Elastic Plastic Spherical Stick Contact for Varying Tangent Modulus and Hardening Rule

2013 ◽  
Vol 1 (1) ◽  
pp. 13-32
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Tangent Modulus ◽  
Isotropic Hardening ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Hardening Models ◽  
Qualitative Similarity ◽  
Elastic Perfectly Plastic

Loading-unloading behavior of a deformable sphere with a rigid flat under full stick contact condition is investigated for varying strain hardening. The study considers various tangent modulus using the finite element software ANSYS. Both the bilinear kinematic hardening and isotropic hardening models are considered. Numerical simulation reveals the qualitative similarity between kinematic and isotropic hardening regarding the variation of interfacial parameters during loading-unloading for various tangent modulus. It is found that the material with kinematic hardening dissipates more energy than the material with isotropic hardening during unloading. However for elastic perfectly plastic material, the loading-unloading behavior is insensitive to hardening model.

scholarly journals Nonlinear Finite Element Analysis of Fiber Reinforced Concrete Slabs

2021 ◽  
Vol 39 (3A) ◽  
pp. 426-439
Author(s):  
Saad A. Al-Taan ◽  
Ayad A. Abdul-Razzak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Plastic Material ◽  
Fiber Reinforced Concrete ◽  
Concrete Slabs ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Reinforced Concrete Slabs ◽  
Elastic Perfectly Plastic

This paper presents a study on the behavior of fiber reinforced concrete slabsusing finite element analysis. A previously published finite element program is used for the nonlinear analysis by including the steel fiber concrete properties. Concrete is represented by degenerated quadratic thick shell element, which is the general shear deformable eight node serendipity element, and the thickness is divided into layers. An elastic perfectly plastic and strain hardening plasticity approach are used to model the compression behavior of concrete.The reinforcing bars were smeared within the concrete layers and assumed as either an elastic perfectly plastic material or as an elastic-plastic material with linear strain hardening. Cracks initiation is predicted using a tensile strength criterion. The tension stiffening effect of the steel fibers is simulated using a descending parabolic stress degradation function, which is based on the fracture energy concept. The effect of cracking in reducing the shear modulus and the compressive strength of concrete parallel to the crack direction is considered. The numerical results showedgood agreement with published experimental results for two fibrous reinforced concrete slabs.

scholarly journals Non-Linear Buckling Analysis of Axially Loaded Column with Non-Prismatic I-Section

2019 ◽  
Vol 5 (3) ◽  
pp. 263
Author(s):  
Adrian Pramudita Dharma ◽  
Bambang Suryoatmono
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Cross Sections ◽  
Plastic Material ◽  
Slenderness Ratio ◽  
Buckling Load ◽  
Coefficient Of Determination ◽  
Average Cross Section ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

In order to use material efficiently, non-prismatic column sections are frequently employed. Tapered-web column cross-sections are commonly used, and design guides of such sections are available. In this study, various web-and-flange-tapered column sections were analysed numerically using finite element method to obtain each buckling load assuming the material as elastic-perfectly plastic material. For each non-prismatic column, the analysis was also performed assuming the column is prismatic using average cross-section with the same length and boundary conditions. Buckling load of the prismatic columns were obtained using equation provided by AISC 360-16. This study proposes a multiplier that can be applied to the buckling load of a prismatic column with an average cross-section to acquire the buckling load of the corresponding non-prismatic column. The multiplier proposed in this study depends on three variables, namely the depth tapered ratio, width tapered ratio, and slenderness ratio of the prismatic section. The equation that uses those three variables to obtain the multiplier is obtained using regression of the finite element results with a coefficient of determination of 0.96.

Ratcheting of Pressurized Piping Subjected to Seismic Loading

1992 ◽  
Vol 114 (3) ◽  
pp. 315-320 ◽  
Author(s):  
R. J. Scavuzzo ◽  
P. C. Lam ◽  
J. S. Gau
Keyword(s):  
Finite Element ◽  
Cyclic Load ◽  
Plastic Material ◽  
Seismic Loading ◽  
Cyclic Plasticity ◽  
Hoop Strain ◽  
Perfectly Plastic ◽  
Bending Loads ◽  
Elastic Plastic Material ◽  
Elastic Perfectly Plastic

The ABAQUS finite element code was used to model a pressurized pipe and subjected to cyclic bending loads to investigate ratcheting. A 1-in. schedule 40 pipe was loaded with a slow (static) cyclic load. The pipe internal pressure was varied from 0 to 6000 psi. Two types of materials were considered: an elastic perfectly plastic and a bilinear elastic-plastic material. Two types of finite elements of the ABAQUS program were compared to analytical solutions to evaluate the element accuracy in the plastic regime. Depending upon loading conditions and specified material properties, three different responses were observed from the finite element analyses: cyclic plasticity, ratcheting of the hoop strain, or shakedown. These analytical results are compared to some experimental measurements.

On the Conditions to Prevent Plastic Shakedown of Structures: Part I—Theory

1993 ◽  
Vol 60 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Castrenze Polizzotto
Keyword(s):  
Mechanical Load ◽  
Plastic Material ◽  
Perfectly Plastic ◽  
Shakedown Theory ◽  
Elastic Perfectly Plastic ◽  
Plastic Shakedown ◽  
Steady Load

For a structure of elastic perfectly plastic material subjected to a given cyclic (mechanical and/or kinematical) load and to a steady (mechanical) load, the conditions are established in which plastic shakedown cannot occur whatever the steady load, and thus the structure is safe against the alternating plasticity collapse. Static and kinematic theorems, analogous to those of classical shakedown theory, are presented.

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