Analytical Prediction of Residual Stresses in Cold Formed Steel Sections with Elastic - Perfectly Plastic Material Model

2017 ◽  
Author(s):  
K Chinnaraj ◽  
R Padmanaban
Keyword(s):  
Residual Stresses ◽  
Plastic Material ◽  
Material Model ◽  
Analytical Prediction ◽  
Perfectly Plastic ◽  
Steel Sections ◽  
Cold Formed Steel ◽  
Elastic Perfectly Plastic

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

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.

Investigation of Residual Stresses in Cold-Formed Steel Sections with Nonlinear Strain-Hardened Material Model

2018 ◽  
Vol 11 (3) ◽  
pp. 229-240
Author(s):  
K. Chinnaraj ◽  
Mangalaramanan Sathya Prasad ◽  
C. Lakshmana Rao ◽  
Padmanaban Ramasamy
Keyword(s):  
Residual Stresses ◽  
Material Model ◽  
Nonlinear Strain ◽  
Steel Sections ◽  
Cold Formed Steel

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

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.

Continuous Strength Method for Aluminium Alloy Structures

2013 ◽  
Vol 742 ◽  
pp. 70-75 ◽  
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.

Analysis and design of steel plate walls: experimental evaluation

2011 ◽  
Vol 38 (1) ◽  
pp. 60-70 ◽  
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.

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

2017 ◽  
Vol 62 (2) ◽  
pp. 879-883 ◽  
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.

Plastic Response Estimation in Repeated Elastic Analyses for Strain Hardening Material Model

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
S. L. Mahmood ◽  
R. Adibi-Asl ◽  
C. G. Daley
Keyword(s):  
Strain Hardening ◽  
Strain Energy ◽  
Plastic Material ◽  
Limit Load ◽  
Material Model ◽  
Element Analysis ◽  
Hardening Material ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

Simplified limit analysis techniques have already been employed for limit load estimation on the basis of linear elastic finite element analysis (FEA) assuming elastic-perfectly-plastic material model. Due to strain hardening, a component or a structure can store supplementary strain energy and hence carries additional load. In this paper, an iterative elastic modulus adjustment scheme is developed in context of strain hardening material model utilizing the “strain energy density” theory. The proposed algorithm is then programmed into repeated elastic FEA and results from the numerical examples are compared with inelastic FEA results.

Verification of Elastic-Perfectly Plastic Methods for Evaluation of Strain Limits: Analytical Comparisons

2014 ◽  
Author(s):  
Peter Carter ◽  
R. I. Jetter ◽  
T.-L. (Sam) Sham
Keyword(s):  
Fatigue Damage ◽  
Plastic Material ◽  
Material Model ◽  
Alloy 617 ◽  
Perfectly Plastic ◽  
Inelastic Analysis ◽  
Accumulated Strain ◽  
Creep Fatigue ◽  
Verification Process ◽  
Elastic Perfectly Plastic

The current rules in Subsection NH for the evaluation of strain limits and creep-fatigue damage using simplified methods based on elastic analysis have been deemed inappropriate for Alloy 617 at temperatures above 1200°F (650°C) because, at higher temperatures, it is not feasible to decouple plasticity and creep; which is the basis for the current simplified rules. To address this issue, proposed code rules have been developed which are based on the use of elastic-perfectly plastic analysis methods and which are expected to be applicable to very high temperatures. The proposed rules are based on the use of an elastic-perfectly plastic material model with a pseudo yield strength selected to ensure that the accumulated strain and creep-fatigue damage with meeting the currently specified limits in Subsection NH. For this phase of the verification process, the proposed rules have been compared using simplified example problems to the results obtained from application of the current Subjection NH rules for both simplified methods and full inelastic analysis. The Subsection NH 316 stainless steel properties data are used for these comparisons. Results of calculations for a testing program underway on Alloy 617 at 950C are given.

Stress concentration factors and elastic-plastic stress and strain predictions for axisymmetric internal projections on hollow tubes subjected to axial loading

1989 ◽  
Vol 24 (1) ◽  
pp. 45-54 ◽  
Author(s):  
S J Hardy ◽  
A R Gowhari-Anaraki
Keyword(s):  
Stress Concentration ◽  
Plastic Material ◽  
Low Cycle Fatigue ◽  
Axial Loading ◽  
Material Model ◽  
Published Data ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Stress Concentration Factors ◽  
Elastic Perfectly Plastic

The finite element method has been used to obtain stress concentration factor data for hollow tubes with axisym-metric internal projections subjected to axial loading. A range of geometries has been considered in the investigation, and the results are complementary to previously published data. Preliminary results from an elastic-plastic analysis of a component with an internal projection are presented. Strain predictions with an elastic-perfectly-plastic material model are found to be between those estimated using linear and Neuber rules for low cycle fatigue life predictions.

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