Application of the Drucker-Prager Elastic-perfectly Plastic Material Model for Performing Finite Element Analyses of Deep Tillage

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.

Download Full-text

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

The Journal of Strain Analysis for Engineering Design ◽

10.1243/03093247jsa521 ◽

2009 ◽

Vol 44 (6) ◽

pp. 407-416 ◽

Cited By ~ 3

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.

Download Full-text

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

Journal of Tribology ◽

10.1115/1.2958081 ◽

2008 ◽

Vol 130 (4) ◽

Cited By ~ 26

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.

Download Full-text

Shakedown Limits of a 90-Degree Pipe Bend Using Small and Large Displacement Formulations

Volume 3: Design and Analysis ◽

10.1115/pvp2006-icpvt-11-93297 ◽

2006 ◽

Author(s):

Hany F. Abdalla ◽

Mohammad M. Megahed ◽

Maher Y. A. Younan

Keyword(s):

Plastic Material ◽

Limit Load ◽

Material Model ◽

Large Displacement ◽

Small Displacement ◽

Pipe Bend ◽

Perfectly Plastic ◽

Loading Patterns ◽

Elastic Perfectly Plastic ◽

Shakedown Limit

In this paper the shakedown limit load is determined for a long radius 90-degree pipe bend using two different techniques. The first technique is a simplified technique which utilizes small displacement formulation and elastic-perfectly-plastic material model. The second technique is an iterative based technique which uses the same elastic-perfectly-plastic material model, but incorporates large displacement effects accounting for geometric non-linearity. Both techniques use the finite element method for analysis. The pipe bend is subjected to constant internal pressure magnitudes and cyclic bending moments. The cyclic bending loading includes three different loading patterns namely; in-plane closing, in-plane opening, and out-of-plane bending. The simplified technique determines the shakedown limit load (moment) without the need to perform full cyclic loading simulations or conventional iterative elastic techniques. Instead, the shakedown limit moment is determined by performing two analyses namely; an elastic analysis and an elastic-plastic analysis. By extracting the results of the two analyses, the shakedown limit moment is determined through the calculation of the residual stresses developed in the pipe bend. The iterative large displacement technique determines the shakedown limit moment in an iterative manner by performing a series of full elastic-plastic cyclic loading simulations. The shakedown limit moment output by the simplified technique (small displacement) is used by the iterative large displacement technique as an initial iterative value. The iterations proceed until an applied moment guarantees a structure developed residual stress, at load removal, equals or slightly less than the material yield strength. The shakedown limit moments output by both techniques are used to generate shakedown diagrams of the pipe bend for a spectrum of constant internal pressure magnitudes for the three loading patterns stated earlier. The maximum moment carrying capacity (limit moment) the pipe bend can withstand and the elastic limit are also determined and imposed on the shakedown diagram of the pipe bend. Comparison between the shakedown diagrams generated by the two techniques, for the three loading patterns, is presented.

Download Full-text

Case Study of Shakedown Evaluation of a Shell With Nozzle Based on Elastic-Plastic Analysis

Volume 1B: Codes and Standards ◽

10.1115/pvp2017-65492 ◽

2017 ◽

Author(s):

Jun Shen ◽

Heng Peng ◽

Liping Wan ◽

Yanfang Tang ◽

Yinghua Liu

Keyword(s):

Temperature Change ◽

Plastic Material ◽

Material Model ◽

Elastic Plastic ◽

Perfectly Plastic ◽

Plastic Analysis ◽

Elastic Perfectly Plastic ◽

Temperature Loads ◽

The Impact

In the past, shakedown evaluation was usually based on the elastic method that the sum of the primary and secondary stress should be limited to 3Sm or the simplified elastic-plastic analysis method. The elastic method is just an approximate analysis, and the rigorous evaluation of shakedown normally requires an elastic-plastic analysis. In this paper, using an elastic perfectly plastic material model, the shakedown analysis was performed by a series of elastic-plastic analyses. Taking a shell with a nozzle subjected to parameterized temperature loads as an example, the impact of temperature change on the shakedown load was discussed and the shakedown loads of this structure at different temperature change rates were also obtained. This study can provide helpful references for engineering design.

Download Full-text

Continuous Strength Method for Aluminium Alloy Structures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.742.70 ◽

2013 ◽

Vol 742 ◽

pp. 70-75 ◽

Cited By ~ 1

Author(s):

Mei Ni Su ◽

Ben Young ◽

Leroy Gardner

Keyword(s):

Aluminium Alloy ◽

Strain Hardening ◽

Plastic Material ◽

Design Method ◽

Material Model ◽

Hardening Material ◽

Perfectly Plastic ◽

Base Curve ◽

Current Design ◽

Elastic Perfectly Plastic

Aluminium alloys are nonlinear metallic materials with continuous stress-strain curves that are not well represented by the simplified elastic, perfectly plastic material model used in many current design specifications. Departing from current practice, the continuous strength method (CSM) is a recently proposed design approach for non-slender aluminium alloy structures with consideration of strain hardening. The CSM is deformation based and employs a base curve to define a continuous relationship between cross-section slenderness and deformation capacity. This paper explains the background and the two key components - (1) the base curve and (2) the strain hardening material model of the continuous strength method. More than 500 test results are used to verify the continuous strength methodas an accurate and consistent design method for aluminium alloy structures.

Download Full-text

Analysis and design of steel plate walls: experimental evaluation

Canadian Journal of Civil Engineering ◽

10.1139/l10-096 ◽

2011 ◽

Vol 38 (1) ◽

pp. 60-70 ◽

Cited By ~ 3

Author(s):

Mehdi H.K. Kharrazi ◽

Carlos E. Ventura ◽

Helmut G.L. Prion

Keyword(s):

Experimental Evaluation ◽

Steel Plate ◽

Plastic Material ◽

Material Model ◽

Steel Plates ◽

Ultimate Capacity ◽

Initial Stiffness ◽

Analysis And Design ◽

Perfectly Plastic ◽

Elastic Perfectly Plastic

In this paper, the effectiveness of the Modified Plate–Frame Interaction (M-PFI) model is evaluated by comparing its outcomes against those from experimental results obtained from a number of steel plate walls (SPWs) tested at different universities. As a result of the comparison, the M-PFI model was found to provide satisfactory predictions for SPW specimens constructed with steel plates welded to column and beam members. The M-PFI model was able to predict the initial stiffness, as well as to evaluate whether the boundary members of the SPW have sufficient capacity to allow for the infill plate to yield entirely. However, the model was found to underestimate the ultimate capacity of the SPW system mainly because, among other reasons, the material model used for its underlying theory is the elastic – perfectly plastic material model.

Download Full-text

A Simplified Approach for the Hydro-Forming Process of Bi-Metallic Composite Pipe

Archives of Metallurgy and Materials ◽

10.1515/amm-2017-0129 ◽

2017 ◽

Vol 62 (2) ◽

pp. 879-883 ◽

Cited By ~ 3

Author(s):

M. Zheng ◽

H. Gao ◽

H. Teng ◽

J. Hu ◽

Z. Tian ◽

...

Keyword(s):

Residual Stress ◽

Plastic Material ◽

Material Model ◽

Forming Process ◽

Simplified Approach ◽

Metallic Composite ◽

Perfectly Plastic ◽

Proposed Model ◽

Composite Pipe ◽

Elastic Perfectly Plastic

AbstractIn this article, it aims to propose effective approaches for hydro-forming process of bi-metallic composite pipe by assuming plane strain and elastic-perfectly plastic material model. It derives expressions for predicting hydro-forming pressure and residual stress of the forming process of bi-metallic composite pipe. Test data from available experiments is employed to check the model and formulas. It shows the reliability of the proposed model and formulas impersonally.

Download Full-text

Use of shakedown maps to assess plastic flow in railway curves

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409719881518 ◽

2019 ◽

Vol 234 (4) ◽

pp. 417-425

Author(s):

SJ Hawksbee ◽

GJ Tucker ◽

M Burstow

Keyword(s):

Finite Element Analysis ◽

Plastic Deformation ◽

Finite Element ◽

Plastic Flow ◽

Material Model ◽

Element Analysis ◽

Contact Conditions ◽

Effective Measure ◽

Perfectly Plastic ◽

Elastic Perfectly Plastic

Plastic deformation of rails can occur on tight curves, which can significantly reduce the rail life. This paper investigated the phenomena of gross plastic deformation, or plastic flow, using multibody vehicle–track interaction and simplified finite element analysis. The focus is on understanding the contact conditions on the low rail of curves and how these differ from those in shakedown maps. To this end, two trial sites are simulated using multibody vehicle–track software. The contact conditions are then compared against several criteria assumed in the derivation of the shakedown maps. A further assumption implicit in the shakedown maps is also investigated by a non-linear finite element analysis. In this case, a more realistic Chaboche material model is used as opposed to the simple linear elastic–perfectly plastic model in the shakedown theory. The results of the finite element analysis are combined with a bespoke indicator of plastic flow to assess the influence of distance to shakedown limits on the likely plastic flow. Finally, a simple interpolation scheme is used to map the finite element results back to the trial sites. The interpolated results for the sites are used to evaluate the influence of running speed and different levels of wheel profile wear. Results suggest that the bespoke indicator defined in this work can be used as an effective measure of plastic flow; this measure is then used to quantify the influence of cant excess on the rates of plastic flow.

Download Full-text

Strain Hardening From Elastic–Perfectly Plastic to Perfectly Elastic Flattening Single Asperity Contact

Journal of Tribology ◽

10.1115/1.4041537 ◽

2018 ◽

Vol 141 (3) ◽

Cited By ~ 5

Author(s):

Hamid Ghaednia ◽

Matthew R. W. Brake ◽

Michael Berryhill ◽

Robert L. Jackson

Keyword(s):

Finite Element ◽

Contact Force ◽

Material Model ◽

Real Contact Area ◽

Contact Radius ◽

Elastic Contact ◽

Elastic Deformations ◽

Real Contact ◽

Perfectly Plastic ◽

Elastic Perfectly Plastic

For elastic contact, an exact analytical solution for the stresses and strains within two contacting bodies has been known since the 1880s. Despite this, there is no similar solution for elastic–plastic contact due to the integral nature of plastic deformations, and the few models that do exist develop approximate solutions for the elastic–perfectly plastic material model. In this work, the full transition from elastic–perfectly plastic to elastic materials in contact is studied using a bilinear material model in a finite element environment for a frictionless dry flattening contact. Even though the contact is considered flattening, elastic deformations are allowed to happen on the flat. The real contact radius is found to converge to the elastic contact limit at a tangent modulus of elasticity around 20%. For the contact force, the results show a different trend in which there is a continual variation in forces across the entire range of material models studied. A new formulation has been developed based on the finite element results to predict the deformations, real contact area, and contact force. A second approach has been introduced to calculate the contact force based on the approximation of the Hertzian solution for the elastic deformations on the flat. The proposed formulation is verified for five different materials sets.

Download Full-text