A Fundamental Study of the Interaction of Residual Stress and Applied Loading on Fracture

2010 ◽  
Author(s):  
C. J. Aird ◽  
M. J. Pavier ◽  
D. J. Smith
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Crack Closure ◽  
Applied Load ◽  
Element Model ◽  
Residual Stress Field ◽  
Fundamental Study ◽  
Analytical Expression ◽  
Applied Loading

This paper presents the results of a fundamental finite-element based study of the crack-closure effects associated with combined residual and applied loading. First, an analytical expression for a representative two-dimensional residual stress field is derived. This residual stress field contains a central compressive region surrounded by an equilibrating tensile region. The analytical expression allows the size and shape of the field to be varied along with the magnitude of the residual stress. The residual stress field is then used as a prescribed initial stress field in a finite element model, in addition to a far field applied load. By introducing cracks of increasing length into these models, charts of stress-intensity-factor versus crack length are produced for different relative magnitudes of residual stress and applied load and for different sizes and shape of the residual stress field. These charts provide insight into the way in which crack-tip conditions evolve with crack growth under conditions of combined residual and applied loading and also enable conditions of crack closure and partial closure to be identified.

A New Method for Predicting the Opening Angle for Soft Tissues

2002 ◽  
Vol 124 (4) ◽  
pp. 347-354 ◽  
Author(s):  
Timothy J. Van Dyke ◽  
Anne Hoger
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Potential Energy ◽  
Biological Tissue ◽  
Soft Tissues ◽  
Element Model ◽  
New Method ◽  
Opening Angle ◽  
Residual Stress Field

The purpose of this paper is to present a simple new method for calculating the opening angle produced by a given residual stress field in a soft biological tissue. The method uses minimization of potential energy, and is therefore named the MPE method. The accuracy of the MPE method is evaluated by comparing the opening angle it predicts to results from a finite element model of the opening angle experiment. We show that the MPE method provides good predictions of the opening angle, and that it is significantly more accurate than two other methods previously used in the literature.

Crack Tip Behaviour in Residual Stress Field: Finite Element Modelling and Neutron Diffraction Measurements

2011 ◽  
Author(s):  
H. Dai ◽  
J. F. Kelleher ◽  
P. J. Withers
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Intensity ◽  
Crack Closure ◽  
Finite Element Modelling ◽  
Applied Load ◽  
Crack Tip ◽  
J Integral ◽  
Residual Stress Field ◽  
Element Modelling

Simple analyses of fracture and fatigue often make use of the stress intensity at a crack tip or the J-integral surrounding it. However, there is no universally accepted method of including the effect of residual stress in these values, even though the qualitative effect of residual stress on crack growth is well known. In this work, we create a cracked compact tension C(T) specimen with a residual stress field that affects the crack tip behaviour, in particular by altering the level of expected crack closure. Neutron diffraction measurements under in situ applied loading reveal strain distributions consistent with an increased level of closure when the crack tip is in a state of compressive residual stress. Through finite element modelling of the samples studied, we show that the residual stress in these samples redistributes as the crack grows, which changes the level of crack closure for any given crack length and applied load. As crack closure is often considered in fatigue analysis by deriving an ‘effective’ stress intensity based on the applied load needed to overcome the closure and open the crack, the model is used to compare this approach with numerical calculations of the J-integral for different crack lengths.

Multipass low-plasticity burnishing induced residual stresses: Three-dimensional elastic-plastic finite element modelling

2004 ◽  
Vol 218 (6) ◽  
pp. 663-668 ◽  
Author(s):  
W Zhuang ◽  
B Wicks
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Moving Contact ◽  
Low Plasticity Burnishing

Low-plasticity burnishing (LPB) is a surface modification process involving complex cyclic plastic deformation that results in the development of a deep residual stress field. In order to achieve an optimal LPB-induced residual stress field for the geometry appropriate to the aircraft engine component, the key parameters of the LPB process, such as burnishing load, burnishing ball size and material properties, need to be determined. For this purpose, a three-dimensional non-linear moving contact finite element model is proposed to simulate the multipass LPB process and to predict the effects of those parameters on the resultant residual stress field. The material constitutive model used in the finite element analysis has been developed from the cyclic stress/strain response obtained from experimental measurements on the material. Prediction of the LPB-induced residual stresses by the finite element model appears to agree reasonably well with X-ray diffraction measurements.

Numerical Study of Welding Sequence on the Residual Stress Field in a Thick-Walled Tee Joint

2011 ◽  
Vol 219-220 ◽  
pp. 1211-1214
Author(s):  
Wei Jiang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Factors Affecting ◽  
Welding Sequence ◽  
Welding Sequences ◽  
Three Dimensional Finite Element

Finite element simulation is an efficient method for studying factors affecting weld-induced residual stress distributions. In this paper, a validated three-dimensional finite element model consisting of sequentially coupled thermal and structural analyses was developed. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were perceived to generate the least distortion in actual welding circumstances, were proposed and their influences on the residual stress fields in a thick-walled tee joint were investigated. Appropriate conclusions and recommendations regarding welding sequences are presented.

Thermal Simulation of an Arbitrary Residual Stress Field in a Fully or Partially Autofrettaged Thick-Walled Spherical Pressure Vessel

2008 ◽  
Author(s):  
M. Perl
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Pressure Vessel ◽  
Stress Fields ◽  
Equivalent Temperature ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Spherical Pressure ◽  
The Ideal

The equivalent thermal load was previously shown to be the only feasible method by which the residual stresses due to autofrettage and its redistribution, as a result of cracking, can be implemented in a finite element analysis, of a fully or partially autofrettaged thick-walled cylindrical pressure vessel. The present analysis involves developing a similar methodology for treating an autofrettaged thick-walled spherical pressure vessel. A general procedure for evaluating the equivalent temperature loading for simulating an arbitrary, analytical or numerical, spherosymmetric autofrettage residual stress field in a spherical pressure vessel is developed. Once presented, the algorithm is applied to two distinct cases. In the first case, an analytical expression for the equivalent thermal loading is obtained for the ideal autofrettage stress field in a spherical shell. In the second case, the algorithm is applied to the discrete numerical values of a realistic autofrettage residual stress field incorporating the Bauschinger effect. As a result, a discrete equivalent temperature field is obtained. Furthermore, a finite element analysis is performed for each of the above cases, applying the respective temperature field to the spherical vessel. The induced stress fields are evaluated for each case and then compared to the original stress. The finite element results prove that the proposed procedure yields equivalent temperature fields that in turn simulate very accurately the residual stress fields for both the ideal and the realistic autofrettage cases.

Numerical Calculation of Residual Stress Corrected J-Integral Using ABAQUS

2014 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Residual Stresses ◽  
Stress Effect ◽  
J Integral ◽  
Residual Stress Field ◽  
Path Independence ◽  
Residual Stress Effect ◽  
Senb Specimen

Residual stresses exist in welded structures due to thermal stresses. Without temperature change, large plastic deformation can result in “cold” residual stresses in a wrinkle or dent in a metallic pipe. For a crack in residual stress field, residual stresses might have strong effect on fracture parameter, the J-integral. In order to ensure its path-independence, different correction methods have been developed in consideration of residual stress effect. Recently, the finite element commercial software ABAQUS adopted one of the correction methods, and is able to calculate the residual stress corrected J-integral. A brief review is first given to the J-integral definition, the conditions of path-independence or path-dependence, and the modifications to consider the residual stress effect. A modified single edge-notched bend (SENB) specimen is then used, and a numerical procedure is developed for ABAQUS to evaluate the path-independence of the residual stress corrected J-integral. Detailed elastic-plastic finite element analyses are performed for the SENB specimen in three-point bending. The residual stress field, crack-tip stress field, and J-integral with and without consideration of residual stresses are discussed.

Numerical Analysis of the Effect of Machining on the Depth of Yield, Maximum Firing Pressure and Residual Stress Profile in an Autofrettaged Gun Tube

2003 ◽  
Vol 125 (3) ◽  
pp. 342-346 ◽  
Author(s):  
Amer Hameed ◽  
R. D. Brown ◽  
J. G. Hetherington
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Optimization Technique ◽  
Circumferential Stress ◽  
Element Model ◽  
Stress Profile ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Residual Stress Profile ◽  
Experimental Findings

A multi-linear kinematic, two dimensional finite element model incorporating Bauschinger effect, developed using ANSYS commercial software is used to determine the effect of machining both at the bore and at the outside diameter, on the depth of yield, maximum firing pressure and final residual stress field present in an autofrettaged gun tube. The model, which is in good agreement with experimental findings, clearly shows that the reduction in maximum compressive circumferential stress is more sensitive to internal machining than to external machining; the depth of yield remains stable and there is no movement of the elastic-plastic interface, relative to its location before material removal. If the internal machining removes material in which reverse yield has occurred, the maximum firing pressure is not affected. The finite element analysis supported by experimental evidence thus leads to an optimization technique for gun tube design.

Three Dimensional Finite Element Analysis of a Split-Sleeve Cold Expansion Process

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
S. Ismonov ◽  
S. R. Daniewicz ◽  
J. C. Newman ◽  
M. R. Hill ◽  
M. R. Urban
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Expansion Process ◽  
Element Analysis ◽  
Cold Expansion ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A cold expansion process is used to prolong the fatigue life of a structure under cyclic loadings. The process produces a beneficial compressive residual stress zone in the hole vicinity, which retards the initiation and propagation of the crack at the hole edge. In this study, a three-dimensional finite element model of the split-sleeve cold expansion process was developed to predict the resulting residual stress field. A thin rectangular aluminum sheet with a centrally located hole was considered. A rigid mandrel and an elastic steel split sleeve were explicitly modeled with the appropriate contact elements at the interfaces between the mandrel, the sleeve, and the hole. Geometrical and material nonlinearities were included. The simulation results were compared with experimental measurements of the residual stress. The influence of friction and the prescribed boundary conditions for the sheet were studied. Differences between the split-sleeve- and the non-split-sleeve model solutions are discussed.

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