Evaluating Plastic Loads in Torispherical Heads Using a New Criterion of Collapse

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Duncan Camilleri ◽  
Donald Mackenzie ◽  
Robert Hamilton
Keyword(s):  
Pressure Vessels ◽  
Plastic Collapse ◽  
Total Work ◽  
Medium Thickness ◽  
Material Models ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Inelastic Analysis ◽  
Elastic Perfectly Plastic ◽  
New Criterion

In ASME Design by Analysis, the plastic load of pressure vessels is established using the twice elastic slope criterion of plastic collapse. This is based on a characteristic load-deformation plot obtained by inelastic analysis. This study investigates an alternative plastic criteria based on plastic work dissipation where the ratio of plastic to total work is monitored. Two sample analyses of medium thickness torispherical pressure vessels are presented. Elastic perfectly plastic and strain hardening material models are considered in both small and large deformation analyses. The calculated plastic loads are assessed in comparison with experimental results from the literature.

Evaluating Plastic Loads in Torispherical Heads Using a New Criterion of Collapse

2006 ◽  
Author(s):  
Duncan Camilleri ◽  
Donald Mackenzie ◽  
Robert Hamilton
Keyword(s):  
Pressure Vessels ◽  
Plastic Collapse ◽  
Total Work ◽  
Medium Thickness ◽  
Material Models ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Inelastic Analysis ◽  
Elastic Perfectly Plastic ◽  
New Criterion

In ASME Design by Analysis, the plastic load of pressure vessels is established using the Twice Elastic Slope criterion of plastic collapse. This is based on a characteristic load-deformation plot obtained by inelastic analysis. This study investigates an alternative plastic criteria based on plastic work dissipation where the ratio of plastic to total work is monitored. Two sample analyses of medium thickness torispherical pressure vessels are presented. Elastic-perfectly plastic and strain hardening material models are considered in both small and large deformation analyses. The calculated plastic loads are assessed in comparison with experimental results from the literature.

Experiment and FEM Simulation on Residual Stress of Cold Expansion Hole

2007 ◽  
Vol 561-565 ◽  
pp. 1783-1786 ◽  
Author(s):  
Xiao Jun Shao ◽  
Jun Liu ◽  
Yong Shou Liu ◽  
Zhu Feng Yue
Keyword(s):  
Residual Stress ◽  
Plastic Material ◽  
Fem Simulation ◽  
Stress Fields ◽  
Material Models ◽  
Hardening Material ◽  
Cold Expansion ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Cold Expansion Hole

A 2D cylindrical plate model has been established to study the distribution of residual stress of cold expansion hole under different interference values. In addition, the effects of material models on residual stress fields are considered also. Experiments are carried out to measure the residual stress of cold expansion hole and verify simulation results. FEM results show, with interference values increasing, the higher residual radial and circumferential stresses are obtained. At same interference value, the residual stress of Hardening Material( HM ) model is much larger than that of Elastic Perfectly Plastic Material( EPPM ) model.

Using Nonlinear Kinematic Hardening Material Models for Elastic-Plastic Ratcheting Analysis

2015 ◽  
Author(s):  
Tim Gilman ◽  
Bill Weitze ◽  
Jürgen Rudolph ◽  
Adrian Willuweit ◽  
Arturs Kalnins
Keyword(s):  
Material Model ◽  
Pressure Vessels ◽  
Growth Strain ◽  
Temperature Dependent ◽  
Material Models ◽  
Hardening Material ◽  
Material Parameters ◽  
Elastic Plastic ◽  
Material Data ◽  
Inelastic Analysis

Applicable design codes for power plant components and pressure vessels demand for a design check against progressive plastic deformation. In the simplest case, this demand is satisfied by compliance with shakedown rules in connection with elastic analyses. The possible non-compliance implicates the requirement of ratcheting analyses on elastic-plastic basis. In this case, criteria are specified on maximum allowable accumulated growth strain without clear guidance on what material models for cyclic plasticity are to be used. This is a considerable gap and a challenge for the practicing CAE (Computer Aided Engineering) engineer. As a follow-up to two independent previous papers PVP2013-98150 ASME [1] and PVP2014-28772 [2] it is the aim of this paper to close this gap by giving further detailed recommendation on the appropriate application of the nonlinear kinematic material model of Chaboche on an engineering scale and based on implementations already available within commercial finite element codes such as ANSYS® and ABAQUS®. Consistency of temperature-dependent runs in ANSYS® and ABAQUS® is to be checked. All three papers together constitute a comprehensive guideline for elasto-plastic ratcheting analysis. The following issues are examined and/or referenced: • Application of monotonic or cyclic material data for ratcheting analysis based on the Chaboche material model • Discussion of using monotonic and cyclic data for assessment of the (non-stabilized) cyclic deformation behavior • Number of backstress terms to be applied for consistent ratcheting results • Consideration of the temperature dependency of the relevant material parameters • Consistency of temperature-dependent runs in ANSYS® and ABAQUS® • Identification of material parameters dependent on the number of backstress terms • Identification of material data for different types of material (carbon steel, austenitic stainless steel) including the appropriate determination of the elastic limit • Quantification of conservatism of simple elastic-perfectly plastic behavior • Application of engineering versus true stress-strain data • Visual checks of data input consistency • Appropriate type of allowable accumulated growth strain. This way, a more accurate inelastic analysis methodology for direct practical application to real world examples in the framework of the design code conforming elasto-plastic ratcheting check is proposed.

A Compressible Elastic, Perfectly Plastic Wedge

1958 ◽  
Vol 25 (2) ◽  
pp. 239-242
Author(s):  
D. R. Bland ◽  
P. M. Naghdi
Keyword(s):  
Plane Strain ◽  
Yield Criterion ◽  
The State ◽  
Hardening Material ◽  
Included Angle ◽  
Elastic Plastic ◽  
Numerical Example ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

Abstract This paper is concerned with a compressible elastic-plastic wedge of an included angle β < π/2 in the state of plane strain. The solution, deduced for an isotropic nonwork-hardening material, employs Tresca’s yield criterion and the associated flow rules. By means of a numerical example the solution is compared with that of an incompressible elastic-plastic wedge in one case (β = π/4) for various positions of the elastic-plastic boundary.

scholarly journals Plastic collapse load analysis for circumferential cracked cylinder under pure torsion

2018 ◽  
Vol 192 ◽  
pp. 02023
Author(s):  
Sutham Arun ◽  
Thongchai Fongsamootr
Keyword(s):  
Limit Load ◽  
Fe Model ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Pure Torsion ◽  
Perfectly Plastic ◽  
Torsion Moment ◽  
Elastic Perfectly Plastic ◽  
Distribution Of Stress ◽  
Cracked Cylinder

This paper aims to analyze the plastic collapse moment of circumferential cracked cylinder under pure torsion using the NSC approach and 3D FE model. The material considered in this work is assumed to be elastic-perfectly plastic. The influences of geometric parameters of crack and cylinder, such as Rm/t, a/t and θ/π on solution of plastic collapse load are also investigated. The analysis shows that for the case of a/t < 0.75, the values of limit torsion moment can be estimated by NSC analysis which provides conservative results. However, for the case of deeper crack, a/t ≥ 0.75, the limit load solution predicted by NSC approach may not be safe, because the distribution of stress at yielding state does not correspond to the NSC assumption. Therefore, the approximated solution of collapse torsion moment for the case of deeper crack with a/t ≥ 0.75 is proposed based on FE analysis.

The Collapse or Ballooning Pressure of Thick-Walled Pressure Vessels

1983 ◽  
Vol 22 ◽  
Author(s):  
B. Crossland
Keyword(s):  
Mild Steel ◽  
Strain Hardening ◽  
Pressure Vessel ◽  
Factor Of Safety ◽  
Plastic Material ◽  
Pressure Vessels ◽  
Bursting Pressure ◽  
Collapse Pressure ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

ABSTRACTDiscussion of the proposed extension of the ASME pressure vessel code to cover operating pressures up to 1.4 GPa (200000 lbf/in2 ) has generated the proposal that two criteria should be used, of which one would be the collapse or ballooning pressure not the bursting pressure. The present paper examines this proposal in relation to extensive data on the collapse and bursting of thick-walled vessels available to the author.It is concluded that the collapse pressure is only readily calculable for materials which approach the behaviour of an elastic/perfectly plastic material. It also appears for materials with significant strain hardening characteristics, such as mild steel, that the collapse pressure considerably underestimates the bursting pressure, whereas for a material which behaves as an elastic/perfectly plastic material the collapse pressure is nearly coincident with the bursting pressure. Consequently if the collapse pressure was adopted and if the factor of safety against collapse was adequate for one material it might be more or less than adequate for another material, which would appear to be unacceptable.

scholarly journals Ratcheting Assessment of a Fixed Tube Sheet Heat Exchanger Subject to In Phase Pressure and Temperature Cycles

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Khosrow Behseta ◽  
Donald Mackenzie ◽  
Robert Hamilton
Keyword(s):  
Heat Exchanger ◽  
Plastic Material ◽  
Sheet Thickness ◽  
Peak Stress ◽  
Material Model ◽  
Tube Sheet ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Inelastic Analysis ◽  
Plastic Shakedown

An investigation of the cyclic elastic-plastic response of an Olefin plant heat exchanger subject to cyclic thermal and pressure loading is presented. Design by analysis procedures for assessment of shakedown and ratcheting are considered, based on elastic and inelastic analysis methods. The heat exchanger tube sheet thickness is nonstandard as it is considerably less than that required by conventional design by formula rules. Ratcheting assessment performed using elastic stress analysis and stress linearization indicates that shakedown occurs under the specified loading when the nonlinear component of the through thickness stress is categorized as peak stress. In practice, the presence of the peak stress will cause local reverse plasticity or plastic shakedown in the component. In nonlinear analysis with an elastic–perfectly plastic material model the vessel exhibits incremental plastic strain accumulation for 10 full load cycles, with no indication that the configuration will adapt to steady state elastic or plastic action, i.e., elastic shakedown or plastic shakedown. However, the strain increments are small and would not lead to the development of a global plastic collapse or gross plastic deformation during the specified life of the vessel. Cyclic analysis based on a strain hardening material model indicates that the vessel will adapt to plastic shakedown after 6 load cycles. This indicates that the stress categorization and linearization assumptions made in the elastic analysis are valid for this configuration.

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.

Loading History Effects for Deepwater S-Lay of Pipelines

2003 ◽  
Author(s):  
Heedo D. Yun ◽  
Ralf R. Peek ◽  
Paul P. Paslay ◽  
Frans F. Kopp
Keyword(s):  
Numerical Solutions ◽  
Loading History ◽  
Material Models ◽  
Plastic Deformations ◽  
Perfectly Plastic ◽  
History Effects ◽  
Departure Angle ◽  
Numerical Finite Element ◽  
Elastic Perfectly Plastic ◽  
The Moment

For economic reasons S-Lay is often preferred to J-Lay. However in very deep water S-Lay requires a high curvature of the stinger to achieve the required close-to-vertical departure angle. This can lead to plastic deformations of the pipe. The high top tension increases the plastic deformations in two ways: firstly it adds an overall tensile component to the strains, thereby increasing the strains at the 12 o’clock position. Secondly it increases the strain concentrations which arise due to discontinuous support of the pipe on the stinger. Typically the pipe is guided over a series of roller beds. The high top tension tends to straighten the spans between the roller beds. To accommodate this (so that the pipe can still follow the stinger), higher curvatures are required at the roller beds. Analytical and numerical solutions are provided to quantify this effect. The analytical solution is fully developed for an elastic-perfectly-plastic pipe, but can also be applied for other material models provided that: (i) the moment-curvature relation for the pipe under tension is known, and (ii) no cyclic plastic ratchetting occurs due to repeated bending of the pipe over the roller beds and straightening in the spans between roller beds. Agreement between the analytical and numerical (finite element) results is excellent, if the proper loading history is used in the numerical simulation. Otherwise the level of strain concentration can be overpredicted.

A High Temperature Primary Load Design Method Based on Elastic Perfectly-Plastic and Simplified Inelastic Analysis

2020 ◽  
Author(s):  
M. C. Messner ◽  
R. I. Jetter ◽  
T.-L. Sham
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Creep Damage ◽  
Elastic Analysis ◽  
Allowable Stress ◽  
Perfectly Plastic ◽  
Inelastic Analysis ◽  
Stress Classification ◽  
Elastic Perfectly Plastic ◽  
Primary Load

Abstract The current primary load design provisions of Section III, Division 5 of the ASME Boiler and Pressure Vessel Code, covering high temperature nuclear components, represent an allowable stress methodology using elastic analysis and stress classification procedures to approximate stress redistribution caused by creep and plasticity. This process is difficult to implement and automate in modern finite element frameworks. This paper describes an alternate primary load design approach that uses elastic perfectly-plastic analysis in conjunction with the reference stress concept to eliminate stress classification while retaining a link to the existing Section III, Division 5 allowable stresses. This global, structural allowable stress check is supplemented with a local check to guard against the initiation of creep damage at local stress discontinuities like headers, nozzles, and other stress concentrations. This check is based on a simple elastic-creep analysis with creep damage calculated with the time-fraction approach, using the current ASME minimum-stress-to-rupture values already provided in the current Code. Both the global and local checks are easily implemented in modern finite element analysis software and greatly simplify Section III, Division 5 primary load design when compared to the current design-by-elastic-analysis method. Several examples demonstrate the utility of the new approach and its potential to reduce over-conservatism.

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