Consideration of damage in the analysis of autofrettage of thick-walled pressure vessels

2016 ◽  
Vol 230 (20) ◽  
pp. 3585-3593 ◽  
Author(s):  
H Altenbach ◽  
GI Lvov ◽  
K Naumenko ◽  
V Okorokov
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Bauschinger Effect ◽  
Pressure Vessels ◽  
Stress Fields ◽  
Constant Thickness ◽  
Process Conditions ◽  
Material Damage ◽  
Damage Processes ◽  
Walled Cylinder

In this study, the influence of material damage and the Bauschinger effect on the autofrettage of thick-walled pressure vessels is investigated. Constitutive equations for the elasto-plastic deformation and damage processes are presented. Boundary value problems for a thick-walled cylinder and for a thick-walled sphere of constant thickness are formulated. Computations are preformed to find the optimum autofrettage pressure, for which the equivalent stresses in the vessel take the minimum value under process conditions. Furthermore, residual stress fields after the autofrettage are analyzed. The results show that the Bauschinger effect and damage lead to essential reduction of favorable residual stresses.

Bauschinger Effect Design Procedures for Autofrettaged Tubes Including Material Removal and Sachs’ Method

1999 ◽  
Vol 121 (4) ◽  
pp. 430-437 ◽  
Author(s):  
A. P. Parker ◽  
J. H. Underwood ◽  
D. P. Kendall
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Material Removal ◽  
Bauschinger Effect ◽  
Numerical Procedure ◽  
Pressure Vessels ◽  
Material Behavior ◽  
Stress Fields ◽  
Complete Analysis ◽  
Elastic Plastic

Autofrettage is used to introduce advantageous residual stresses into pressure vessels and to enhance their fatigue lifetimes. The Bauschinger effect serves to reduce the yield strength in compression as a result of prior tensile plastic overload and can produce lower compressive residual hoop stresses near the bore than are predicted by “ideal” autofrettage solutions (elastic/perfectly plastic without Bauschinger effect). A complete analysis procedure is presented which encompasses representation of elastic-plastic uniaxial loading material behavior and of reverse-loading material behavior as a function of plastic strain during loading. Such data are then combined with some yield criterion to accurately predict elastic-plastic residual stress fields within an autofrettaged thick cylinder. Pressure for subsequent reyielding of the tube is calculated. The numerical procedure is further used to determine residual stress fields after removal of material from inside diameter (i.d.) and/or outside diameter (o.d.), including the effects of any further plasticity. A specific material removal sequence is recommended. It is shown that Sachs’ experimental method, which involves removing material from the i.d., may very significantly overestimate autofrettage residual stresses near the bore. Stress ranges and stress intensity factors for cracks within such stress fields are calculated together with the associated fatigue lifetimes as such cracks propagate under cyclic pressurization. The loss of fatigue lifetime resulting from the Bauschinger effect is shown to be extremely significant.

Stress Concentration and Stress Intensity for Pressurized Eroded Autofrettaged Thick Cylinders With Bauschinger Effect

2010 ◽  
Author(s):  
Q. Ma ◽  
C. Levy ◽  
M. Perl
Keyword(s):  
Stress Intensity ◽  
Stress Concentration ◽  
Bauschinger Effect ◽  
Thermal Loading ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Short Cracks ◽  
Finite Element Package ◽  
Von Mises ◽  
Walled Cylinder

Our previous studies have shown that stress intensity factors (SIFs) are influenced considerably from the presence of the Bauschinger Effect (BE) in thick-walled pressurized cracked cylinders. For some types of pressure vessels, such as gun barrels, working in corrosive environment, in addition to acute temperature gradients and repetitive high-pressure impulses, erosions can be practically induced. Those erosions cause stress concentration at the bore, where cracks can readily initiate and propagate. In this study, The BE on the SIFs will be investigated for a crack emanating from an erosion’s deepest point in a multiply eroded autofrettaged, pressurized thick-walled cylinder. A commercial finite element package, ANSYS, was employed to perform this type of analysis. A two-dimensional model, analogous to the authors’ previous studies, has been adopted for this new investigation. Autofrettage with and without BE, based on von Mises yield criterion, is simulated by thermal loading and the SIFs are determined by the nodal displacement method. The SIFs are evaluated for a variety of relative crack lengths, a0/t = 0.01–0.45 emanating from the tip of the erosion of different geometries including (a) semi-circular erosions of relative depths of 1–10 percent of the cylinder’s wall thickness, t; (b) arc erosions for several dimensionless radii of curvature, r′/t = 0.05–0.4; and (c) semi-elliptical erosions with ellipticities of d/h = 0.5–1.5, and erosion span angle, α, from 6 deg to 360 deg. The effective SIFs for relatively short cracks are found to be increased by the presence of the erosion and further increased due to the BE, which may result in a significant decrease in the vessel’s fatigue life. Deep cracks are found to be almost unaffected by the erosion, but are considerably affected by BE.

Waterjet Machining and Peening of Metals

1999 ◽  
Vol 122 (1) ◽  
pp. 90-95 ◽  
Author(s):  
M. Ramulu ◽  
S. Kunaporn ◽  
D. Arola ◽  
M. Hashish ◽  
J. Hopkins
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Surface Integrity ◽  
Stress Fields ◽  
Abrasive Waterjet ◽  
Material Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Waterjet Machining ◽  
Measurement And Evaluation

An experimental study was conducted to determine the influence of high-pressure waterjet (WJ) peening and abrasive waterjet (AWJ) machining on the surface integrity and texture of metals. A combination of microstructure analysis, microhardness measurements, and profilometry were used in determining the depth of plastic deformation and surface texture that result from the material removal process. The measurement and evaluation of residual stress was conducted with X-ray diffraction. The residual stress fields resulting from treatment were analyzed to further distinguish the influence of material properties on the surface integrity. It was found that waterjet peening induces plastic deformation at the surface layer of metals as good as shot peening. The degree of plastic deformation and the state of material surface were found to be strongly dependent on the peening conditions applied. [S0094-9930(00)00801-5]

Use of A True Material Constitutive Model for Stress Analysis of A Swage Autofrettaged Tube Including Asme Code Comparison

2021 ◽  
Author(s):  
Zhong Hu ◽  
Anthony P Parker
Keyword(s):  
Residual Stress ◽  
Constitutive Model ◽  
Stress Analysis ◽  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Pressure Vessels ◽  
Material Behavior ◽  
Elastoplastic Material ◽  
Material Constitutive Model ◽  
Deformation Mechanics

Abstract This work reports a new finite element analysis (FEA)-based user programmable function (UPF) featuring true material constitutive behavior with proper algorithms for accurate stress analysis of swage autofrettage of high-strength thick-walled cylinders. The material constitutive model replicates an existing Bauschinger-effect characterization (BEC). This incorporates elastoplastic material behavior during loading. Reversed loading includes a reduced elastic modulus and nonlinear plasticity resulting from the Bauschinger effect (BE), both depend upon the maximum level of loading plastic strain. Swage autofrettage case studies identify the difference in stress distributions based on different material models: a bilinear isotropic material model, a bilinear kinematic hardening model, and the user defined model that features the BEC. Development and integration of such a UPF into a standard FEA package is a crucial unresolved and fundamental modeling issue relating to re-yield, fatigue and fracture of modern swaged cylinders and pressure vessels. It will not only provide a fundamental understanding of the deformation mechanics of the tube during the swage autofrettage process and ensure optimal process parameters are achieved, but also provide guidance for material selection, design and optimization of the manufacturing processes for high intensity cylindrical parts, a potential multibillion-dollar market. Near-bore residual stresses for the BEC case are noteworthy and reported in detail, e.g., axial residual stress is tensile and hoop residual stress exhibits a distinct slope reversal, unlike hydraulic autofrettage, indicating the possible need to re-assess the ASME Pressure Vessel Code (correction for BE) regarding swage autofrettage.

A destructive procedure to determine the residual stresses in thick-walled cylindrical pressure vessels

1994 ◽  
Vol 29 (1) ◽  
pp. 57-63 ◽  
Author(s):  
H L Stark ◽  
J Bau ◽  
D W Kelly
Keyword(s):  
Residual Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Pressure Vessels ◽  
Stress Fields ◽  
Practical Application ◽  
Strain Variation ◽  
Sequence Matching ◽  
Original Distribution ◽  
Measured Strain

The aim of this work is to develop a procedure for determining the three-dimensional residual stress fields in forged cylindrical pressure vessels. The procedure involves the destructive machining of the cylinder. Strain gauges record the strain variation on the outer surface of the cylinder as the inner surface is machined. A finite element model is then constructed, reversing the machining sequence, matching the increments in measured strain, and thus cumulatively arriving at the original distribution of residual stress. Examples include a numerical simulation for a thick disk and a practical application to thick-walled forged cylinders.

Prediction of Residual Stresses in an Autofrettaged Thick–Walled Cylinder

1983 ◽  
Vol 22 ◽  
Author(s):  
Peter C. T. Chen
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Bauschinger Effect ◽  
Residual Stress Distribution ◽  
Effect Factor ◽  
Hardening Effect ◽  
Loading And Unloading ◽  
Reverse Yielding ◽  
Walled Cylinder ◽  
Elastic Unloading

ABSTRACTMost of the earlier results for residual stresses are based on the assumption of elastic unloading. In this paper, the prediction of residual stresses for the case of reverse yielding including the combined Bauschinger and hardening effect will be reported for an autofrettaged thick-walled cylinder. The Bauschinger effect factor is varying as a function of overstrain. The strain-hardening effect is considered with different parameters used for loading and unloading process. The new results indicate that the influence of the combined Bauschinger and hardening effect on residual stress distribution is significant.

Residual Stress Induced by Waterjet Peening: A Finite Element Analysis

2004 ◽  
Vol 126 (3) ◽  
pp. 333-340 ◽  
Author(s):  
S. Kunaporn ◽  
M. Ramulu ◽  
M. G. Jenkins ◽  
M. Hashish
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Stress Fields ◽  
Process Conditions ◽  
Workpiece Material ◽  
Element Analysis ◽  
Compressive Stresses ◽  
Interfacial Pressure

The concept of multiple droplet impacts resulting from ultra high-pressure waterjet (UHPWJ) was used to develop a mathematical model to describe the effect of interfacial pressure on the underlying workpiece material. A non-linear elastic-plastic finite element analysis (FEA) was carried out in this study using the interfacial pressure model to predict residual compressive stresses. This three-dimensional FEA model was based on quasi-static considerations to provide prediction of both magnitude and depth of residual stress fields in a 7075-T6 aluminum alloy (A17075-T6). Results of the FEA modeling were in good agreement with experimental measurements. Effects of applied pressures on the residual stress fields are also presented and discussed as a method of estimating high-pressure waterjet induced compressive stresses under varying process conditions for peening.

Autofrettaged Cylindrical Vessels and Bauschinger Effect: An Analytical Frame for Evaluating Residual Stress Distributions

2001 ◽  
Vol 124 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Paolo Livieri ◽  
Paolo Lazzarin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Explicit Form ◽  
Analytical Solutions ◽  
Bauschinger Effect ◽  
Superposition Principle ◽  
Pressure Vessels ◽  
Material Behavior ◽  
Stress Distributions ◽  
Hardening Law

The paper reports analytical solutions valid for residual stresses in cylindrical pressure vessels subjected to autofrettage. The material behavior is thought of as obeying a generic monotonic σ−ε curve and exhibiting the Bauschinger effect during the unloading phase. Under linear and power-hardening conditions, the solution is given in an explicit form. The circumstances under which it is possible to apply the superposition principle also in the presence of localized plasticity are clearly identified. When possible, the final stresses can be obtained by using in an appropriate manner the stress expressions related to the loading phase. Finally, the influence on residual stresses, both of the hardening law and of the shape of the unloading σ−ε curve, is discussed.

Residual Stress Fields Under Different Clamping Conditions in Circumferentially Welded Thin-Walled Cylinders

2008 ◽  
Author(s):  
Afzaal M. Malik ◽  
Ejaz M. Qureshi ◽  
Naeem Ullah Dar ◽  
Iqbal Khan
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Corrosion ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Pressure Vessels ◽  
Stress Fields ◽  
Shop Floor ◽  
High Tech ◽  
Thin Walled

Arc welding is a reliable joining method widely utilized in nuclear, pressure vessels, aerospace and aeronautical structures to ensure the intended in service behaviour during the thermal and/or pressure loadings. Weld induced deformations and high residual stresses often occur during the course of welding. These cause significant threats for the structural integrity of the nuclear power plant components, particularly in stress corrosion inhibited environments owing to the risk of stress corrosion cracking (SCC). In this research, the consequences of five different structural boundary conditions on the evolution of residual stress fields after the welding are investigated. Both experimental and numerical simulations based on finite element modeling are employed during the course of investigation. Full three-dimensional FE models for the circumferentially, arc welded thin-walled cylinders are developed in ANSYS®. The complex coupled, thermo-mechanical phenomenon during the welding is simulated by sequentially coupled approach enhanced by user written APDL subroutines. The role of welding restraints in minimizing / optimizing the residual stresses is presented and discussed in detail. The result reveals that residual stresses show weak dependence on the degree of the restraints. Although the stress levels slightly varies in magnitude, but similar trend is observed for all the structural clamping conditions under study. Simulation results validated through full-scale experiments with high-tech reliably instrumented welding and measuring equipments shows promising features of the developed modelling and simulation strategy for use in shop floor applications.

3D Finite Element Modeling of the Swage Autofrettage Process Including the Bauschinger Effect

2007 ◽  
Author(s):  
E. Troiano ◽  
J. H. Underwood ◽  
R. R. de Swardt ◽  
A. M. Venter ◽  
A. P. Parker ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Pressure Vessel ◽  
Bauschinger Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Pressure Vessels ◽  
Reverse Loading ◽  
Inherent Nature ◽  
Materials Used

The autofrettage process is a method that produces tensile plastic deformation during the overloading of a pressure vessel which reverses and becomes compressive during unloading. This process produces favorable compressive residual hoop stresses at the bore of the pressure vessel, and results in an increase in the life of the component. In thick walled pressure vessels this process can be accomplished with either a hydraulic or mechanical overloading process. These processes produce different residual stress fields by their inherent nature. The Bauschinger effect, which is observed in most of the materials used in thick walled pressure vessels, is a phenomenon which results in lower reverse loading stresses than those predicted with the classic techniques of Hill and others. The phenomenon is a strong function of the amount of plastic strain during the initial loading of the pressure vessel and results in losses of reverse loading strength of up to 40% in A723 and HB7 steels. A quasi-static three dimensional axi-symmetric finite element model of the swage mandrel autofrettage process of a thick walled pressure vessel is presented in this work. It includes the results of several methodologies for predicting the reduced reverse loading stresses resulting from the Bauschinger effect. The FE results are then shown to compare favorably with neutron diffraction residual stress measurements and yield pressure tests.

Sign in / Sign up

Export Citation Format

Share Document