scholarly journals Residual Stress State in Single-Edge Notched Tension Specimen Caused by the Local Compression Technique

2016 ◽  
Vol 63 (4) ◽  
pp. 635-645 ◽  
Author(s):  
Yifan Huang ◽  
Wenxing Zhou
Keyword(s):  
Residual Stress ◽  
Crack Opening ◽  
Three Dimensional ◽  
Single Pair ◽  
Finite Element Analyses ◽  
Single Edge ◽  
Tension Specimen ◽  
Compression Technique ◽  
Residual Stress State ◽  
Uncracked Ligament

Abstract Three-dimensional (3D) finite element analyses (FEA) are performed to simulate the local compression (LC) technique on the clamped single-edge notched tension (SE(T)) specimens. The analysis includes three types of indenters, which are single pair of cylinder indenters (SPCI), double pairs of cylinder indenters (DPCI) and single pair of ring indenters (SPRI). The distribution of the residual stress in the crack opening direction in the uncracked ligament of the specimen is evaluated. The outcome of this study can facilitate the use of LC technique on SE(T) specimens.

Evaluation of Residual Stresses in Small Diameter Stainless Steel Pipe Welds by Two-Dimensional and Three-Dimensional Finite Element Analyses

2014 ◽  
Author(s):  
Francis H. Ku ◽  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Steel Pipe ◽  
3D Analysis ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Stainless Steel Pipe

Two-dimensional (2D) and three-dimensional (3D) weld-induced residual stress finite element analyses have been performed for 2-inch Schedule 80 Type-304 stainless steel pipe sections joined by a multi-layer segmented-bead pipe weld. The analyses investigate the similarities and differences between the two modeling approaches in terms of residual stresses and axial shrinkage induced by the pipe weld. The 2D analyses are of axisymmetric behavior and evaluate two different pipe end constraints, namely fixed-fixed and fixed-free, while the 3D analysis approximates the non-axisymmetric segmented welding expected in production, with fixed-free pipe end constraints. Based on the results presented, the following conclusions can be drawn. The welding temperature contour results between the 2D and 3D analyses are very similar. Only the 3D analysis is capable of simulating the non-axisymmetric behavior of the segmented welding technique. The 2D analyses yield similar hoop residual stresses to the 3D analysis, and closely capture the maximum and minimum ID surface hoop residual stresses from the 3D analysis. The primary difference in ID surface residual stresses between the 2D fixed-fixed and 2D fixed-free constraints cases is the higher tensile axial stresses in the pipe outside of the weld region. The 2D analyses under-predict the maximum axial residual stress compared to the 3D analysis. The 2D ID surface residual stress results tend to bound the averaged 3D results. 2D axisymmetric modeling tends to significantly under-predict weld shrinkage. Axial weld shrinkage from 3D modeling is of the same magnitude as values measured in the laboratory on a prototypic mockup.

Finite Element Analyses for Thickness Effects on J-Integral Testing using Non-Standard Testing Specimens

2004 ◽  
Vol 261-263 ◽  
pp. 693-698
Author(s):  
J.S. Kim ◽  
Young Jin Kim ◽  
S.M. Cho
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Three Dimensional ◽  
Specimen Thickness ◽  
J Integral ◽  
Finite Element Analyses ◽  
Single Edge ◽  
Fracture Toughness Testing ◽  
Standard Testing ◽  
Toughness Testing

This paper compiles solutions of plastic η factors for standard and non-standard fracture toughness testing specimens, via detailed three-dimensional (3-D) finite element (FE) analyses. Fracture toughness testing specimens include a middle cracked tension (M(T)) specimen, SE(B), single-edge cracked bar in tension (SE(T)) and C(T) specimen. The ligament-to-thickness ratio of the specimen is systematically varied. It is found that the use of the CMOD overall provides more robust experimental estimation than that of the LLD, for all cases considered in the present work. Moreover, the estimation based on the load- CMOD record is shown to be insensitive to the specimen thickness, and thus can be used for testing a specimen with any thickness.

Estimates of Elastic Crack Opening Displacements of Slanted Through-Wall Cracks in Plate and Cylinder

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Nam-Su Huh ◽  
Do-Jun Shim ◽  
Yeon-Sik Yoo ◽  
Suhn Choi ◽  
Keun-Bae Park
Keyword(s):  
Finite Element ◽  
Crack Opening ◽  
Three Dimensional ◽  
Bending Moment ◽  
Element Model ◽  
Finite Element Analyses ◽  
Opening Displacement ◽  
Elastic Crack ◽  
Leak Before Break ◽  
The Finite Element Model

This paper provides tractable solutions for elastic crack opening displacement (COD) of slanted through-wall cracks in plates and cylinders. The solutions were developed via detailed three dimensional elastic finite element analyses. The COD values were calculated along the thickness at the center of the crack. As for the loading conditions, only remote tension was considered for the plates, whereas remote tension, global bending moment, and internal pressure were considered for the cylinders. The finite element model employed in the present analysis was verified by using existing solutions for a cylinder with an idealized circumferential through-wall crack. The present results can be used to evaluate leak rates of slanted through-wall cracks, which can be used as a part of a detailed leak-before-break analysis considering more realistic crack shape development.

Geometrical and Welding Conditions on Through-Thickness Residual Stress in Primary Piping of Girth Welded Joints

2008 ◽  
Vol 580-582 ◽  
pp. 573-576 ◽  
Author(s):  
Jinya Katsuyama ◽  
Masahito Mochizuki ◽  
Hiroaki Mori ◽  
W. Asano ◽  
Gyu Baek An ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Stress Corrosion Cracking ◽  
Welded Joints ◽  
Three Dimensional ◽  
Finite Element Analyses ◽  
Welding Zone ◽  
Butt Welding ◽  
Welding Joints

Recently, stress corrosion cracking (SCC) of primary piping of stainless steel has been observed. SCC is considered to initiate and progress at near the welding zone in butt-welded pipes, because of the tensile residual stress introduced by welding. In present work, three-dimensional and axisymmetric thermo-elastic-plastic finite element analyses have been carried out, in order to clarify the effect of geometrical and welding conditions on through-thickness residual stress. In particular, butt-welding joints of SUS316L pipes have been examined. The residual stress was simulated by three-dimensional and axisymmetric models and the results were compared and discussed in detail.

The effect of microscale residual stress from thermal cooldown on the nanoindentation properties of fibre-reinforced composites

2016 ◽  
Vol 50 (29) ◽  
pp. 4147-4158 ◽  
Author(s):  
M Hardiman ◽  
TJ Vaughan ◽  
CT McCarthy
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fibre Composite ◽  
Three Dimensional ◽  
Interfacial Region ◽  
Indentation Modulus ◽  
Reinforced Composites ◽  
Carbon Fibre Composite ◽  
Residual Stress State ◽  
Fibre Reinforced Composites

A two-step finite element framework is presented that examines the effect of microscale thermal residual stress on the nanoindentation properties of fibre-reinforced composites. Firstly, micromechanical modelling is used to determine the residual stress state following thermal cooldown of a carbon-fibre composite material from cure temperature. A three-dimensional finite element nanoindentation model is then used to characterise the effects of residual stress on material properties determined by nanoindentation theory. The results show that the hardness of the matrix pockets decreases following thermal cooldown due to the existence of equibiaxial tensile residual stresses. The hardness property is also found to decrease for the majority of interfacial region stress states, while the microstructural areas where the effects of the residual stress are nullified are determined. The indentation modulus property is relatively insensitive to the microstructural residual stress, and thus is the recommended indentation property to be determined when carrying out a comparative parametric analysis between microstructural regions. The property changes are shown to be insensitive to any errors associated with contact area estimation using the Oliver and Pharr method.

Part Repair and Start/Stop Effects and Three Dimensional Residual Stress in Dissimilar Metal Welds

2015 ◽  
Author(s):  
F. W. Brust ◽  
E. Punch ◽  
E. Kurth
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Nuclear Power ◽  
Power Plants ◽  
Three Dimensional ◽  
Filler Materials ◽  
Piping System ◽  
Dissimilar Metal ◽  
Residual Stress State ◽  
Weld Residual Stress

PWR nuclear power plants have dissimilar metal (DM) welds at many junctions between the vessels and the piping. The DM welds are made with Alloy 82 filler materials between carbon steel and stainless steel. These are potentially susceptible to Primary Water Stress Corrosion Cracking (PWSCC). PWSCC is mainly driven by the tensile weld residual stresses (WRS) that develop during fabrication of the piping system. In particular, weld repairs that often occur during the weld fabrication process also play a strong role in the development of the weld residual stress state in and near the DM welds. Most weld residual stress analyses performed to date in order to characterize the weld residual stress state in DM welds for PWSCC crack growth, leakage, and subsequent failure used axis-symmetric assessments. The purpose of this work is to provide direct assessment of the appropriateness of this axis-symmetric assumption on the WRS by comparison with full three dimensional analyses of several nozzles. In particular, weld start stop effects on the original weld will be assessed. In addition, the effect of partial arc weld repairs will be included. Repair cases considered include 15% and 50% deep repairs of length 48-degree and 96-degree of the circumference, along with the baseline case with no repair. The more complex three dimensional WRS state from the three dimensional analyses are compared to the corresponding axis-symmetric solutions and guidelines regarding the appropriateness of 2D solutions are discussed. Finally, some limited calculations of stress intensity factors at locations along the repair are presented.

Influence of Cooling Rate on Predicted Weld Residual Stress Buildup in a Thick-Walled Piping Intersection

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Nuclear Power ◽  
Three Dimensional ◽  
Modeling Technique ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Residual Stress State ◽  
External Cooling

Welded, thick-walled piping intersections are widely used in many engineering applications including the offshore and nuclear power industries. These components are often fabricated by multipass welding, which inevitably introduces undesirable residual stresses. In this paper, weld-induced residual stresses in a thick-walled piping intersection were predicted using a validated, full three dimensional, sequentially coupled thermomechanical finite element modeling technique. The moving heat source was simulated by imposing body heat flux onto the newly activated elements progressing along the circumferential weld path around the intersection during each pass. The effect of cooling rate on the final residual stress state, especially at critical areas where the peak residual stresses are located, was then investigated by applying different convective heat transfer coefficients to the exposed piping intersection surfaces. It was found that the magnitudes and overall spatial distributions of residual stresses were very sensitive to cooling rate. Residual stresses on the outer surfaces of the component can be significantly reduced by external cooling. On the other hand, cooling the inner surfaces can dramatically convert residual stresses from tensile to compressive in these regions. The results and modeling technique presented in this paper show that residual stress profiles in multipass welded complex geometries can be efficiently optimized through convenient cooling rate control.

Asymmetric Shielding in Interfacial Fracture Under In-Plane Shear

1992 ◽  
Vol 59 (2) ◽  
pp. 295-304 ◽  
Author(s):  
K. M. Liechti ◽  
Y. S. Chai
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Crack Opening ◽  
Three Dimensional ◽  
Inelastic Behavior ◽  
Finite Element Analyses ◽  
Plane Shear ◽  
Plastic Dissipation ◽  
Wide Range ◽  
Interference Measurements

The toughness of a glass/epoxy interface was measured over a wide range of mode mixes. A toughening effect was associated with increasing positive and negative inplane shear components. Optical interference measurements of normal crack opening displacements near the crack front and complementary finite element analyses were used to examine near-front behavior during crack initiation. Estimates of the toughening based on plastic dissipation, bulk viscoelastic dissipation, and interface asperity shielding did not fully account for the measured values. The results suggest that the inelastic behavior of the epoxy, frictional, and, perhaps, three-dimensional effects should be considered.

Influence of Cooling Rate on Predicted Weld Residual Stress Build-Up in a Thick Walled Piping Intersection

2008 ◽  
Author(s):  
Wei Jiang ◽  
Kadda Yahiaoui
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Nuclear Power ◽  
Three Dimensional ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Residual Stress State ◽  
External Cooling ◽  
Element Simulation

Welded, thick-walled piping intersections are widely used in many engineering applications including the offshore and nuclear power industries. These components are often fabricated by multipass welding which inevitably introduces undesirable residual stresses. In this contribution, weld-induced residual stresses in a thick-walled piping intersection were predicted using a validated, full three dimensional, sequentially coupled thermo-mechanical finite element simulation. The effect of cooling rate on the final residual stress state, especially at critical areas where the peak residual stresses are located, was then investigated by applying different convective heat transfer coefficients to the exposed piping intersection surfaces. It was found that the magnitudes and overall spatial distributions of residual stresses were very sensitive to cooling rate. Residual stresses on the outer surfaces of the component can be significantly reduced by external cooling. On the other hand, cooling the inner surfaces can dramatically convert residual stresses from tensile to compressive in these regions. The results and modeling technique presented in this contribution show that residual stress profiles in multipass welded complex geometries can be efficiently optimized through convenient cooling rate control.

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