Download or read book Evaluation of Sub Surface Residual Stress by Ultrasonic Method and Finite Element Analysis of Welding Process in a Monel Pressure Vessel written by Yashar Javadi and published by . This book was released on 2016 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Welding of nickel-based alloys is increasingly used in the industry to manufacture various important structures in the marine industries, chemical processing, etc. This study investigates evaluation of sub-surface residual stresses, which are produced by the welding process in a pressure vessel made from Monel 400 alloy. The residual stresses are experimentally measured by ultrasonic method in which longitudinal critically refracted (LCR) waves are propagated inside the specimen to evaluate the effect of stress on the wave velocity. Any difference in the wave velocity could be transformed to the material stress by using acoustoelasticity relations. A nondestructive hydro-test process is used to measure the acoustoelastic constant, which is an important material property needed to be embedded in the acoustoelasticity relations. By using a different frequency range than the ultrasonic transducers, the LCR wave penetrates in different depths of the specimen to measure the sub-surface stresses. The welding processes are also numerically analyzed by a 3D thermo-mechanical finite-element (FE) model, which is validated by hole-drilling stress-measurement method. The residual stresses calculated by FE simulation are then compared with those obtained from the ultrasonic stress measurement and an acceptable agreement is achieved. It is demonstrated that the sub-surface residual stresses of the Monel pressure vessel could be accurately evaluated by combination of the FE simulation and stress measurement implemented by the LCR waves.

Download or read book Computer Aided Nondestructive Evaluation Method of Welding Residual Stresses by Removing Reinforcement of Weld Proposal of a New Concept and Its Verification written by H. Nakamura and published by . This book was released on 2000 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new method (the bead flush method) is proposed to estimate welding residual stresses non-destructively. First, the reinforcement of the weld is removed. Then from released strains on the surface due to removal, eigenstrain distributions are estimated by an inverse analysis. Finally, residual stresses are determined by the finite element method (FEM) using estimated eigenstrains as boundary conditions.

Download or read book Finite Element Modeling of Residual Stresses in Electroslag Butt Welds written by and published by . This book was released on 2000 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Weld Mechanics Constraint and Weld Fracture written by F. Brust and published by . This book was released on 2002 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation These 26 technical papers from the August 2002 conference present novel analytical and experimental methods related to fracture mechanics, computational weld mechanics, and residual stresses for evaluation of the structural integrity and reliability of pressure vessels and piping. Bi-metallic welds, finite elements and constraint effects on fracture, and large scale weld modeling of structures are addressed. Topics include fracture assessment of a clad steel using the SINTAP procedure, lump pass welding simulation technology for shipbuilding applications, and the determination of constraint-modified J-R curves for carbon steel storage tanks. No subject index. Annotation c. Book News, Inc., Portland, OR (booknews.com).

Download or read book Review of Ultrasonic Velocity Methods of Determining Residual Stress written by Stuart James Rumble and published by . This book was released on 1985 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual stress is the stress remaining in a body when all external forces have been removed. Residual stresses can occur as a result of fabrication, assembly, load history, heat treatment or welding. They may be compressive or tensile, and often contribute to the occurrence of component failure. The contribution of these stresses to premature structural failure has long been recognized. However their measurement has usually been difficult and in many cases not possible. Recognition of the benefits of knowing the value of residual stresses has led to recent efforts to improve the capability of known methods of measuring them and to the development of new techniques. The residual stresses in a body can be divided into two classes depending on the extent of the stress. In typical engineering materials, residual microstresses extend over a few grains, whereas residual macrostresses which are most amenable to the practical measurement methods discussed in this paper. It notes that while velocity methods have not been refined to the stage of practical use, they show considerable promise. The theoretical basis, and the experimental techniques of the ultrasonic methods are reviewed with emphasis on the separation of the competing effects of texture and stress on ultrasonic velocity. Keyword: Australia.

Download or read book Non Destructive Evaluation of Residual Stresses in Welding written by Santanu Saha and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During welding, due to the highly localized transient heat input, considerable residual stresses and deformations may occur. Welding residual stresses and welding distortion may greatly impair manufacturing and strength. Residual stresses are internal forces without external forces acting. The total residual stresses superimpose on the stresses from the external load, i.e., the load stresses. Residual stresses are the result of microstructural deformations, e.g., dislocations etc. and can be divided as follows: i) volumetric (or ,Äúdilatoric,Äù) ii) distortional (or ,Äúdeviatoric,Äù). Volumetric strain generally is caused by sectioning by thermal expansion, chemical conversion, microstructural transformation or change in state; distortional strain is generally caused by time-independent plastic or time-dependent visco-plastic deformation. There are several methods available to measure the residual stresses or strains non-destructively. One of them is X-ray diffraction. X-rays are diffracted crystal lattices and produce interference phenomena, from which it is possible to draw conclusions relating to the interplanar spacing of the lattice. Other methods are the neutron diffraction method, ultrasonic method and the magnetostriction method. In the magnetostriction or Barkhausen noise method, the stress state is deduced from the value of the local magnetization restraint. The magnetic flux density in a ferromagnetic material subjected to a time-varying magnetic field does not change in a strictly continuous way, but rather by small, abrupt, discontinuous increments called Barkhausen jumps. The jumps are due primarily to discontinuous movements of boundaries between small magnetically saturated regions called magnetic domains in the material. This chapter describes the causes and measurement of residual stress induced during welding.

Download or read book Experimental and Analytical Evaluation of Enhancement in Fatigue Resistance of Welded Details Subjected to Post weld Ultrasonic Impact Treatment written by Sougata Roy and published by . This book was released on 2005 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geometric effect of UIT was analytically evaluated based on notch stress approach. Endurance limit modified by fatigue notch factor and mean load effects provided an excellent estimate of fatigue limit. Spatial residual stress distribution due to welding and subsequent treatment was simulated by finite element analysis.

Download or read book Residual Stress Evaluation with Contour Method for Thick Butt Welded Joint written by Jiangchao Wang and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thick plate with high tensile strength steel is increasingly employed for offshore structure fabrication, and welding residual stress is essential for assessment of mechanical performance and fatigue toughness. Therefore, it has been becoming the research issue to evaluate the distribution and magnitude of welding residual stress during butt welding of thick plate. With its advantages, contour method (CM) can be used for longitudinal residual stress evaluation by means of measuring sectional shrinkage after cutting the butt welded joint perpendicular to the welding line. Meanwhile, inverse finite element method (IFEM) code is programmed with C++ language to analyze the measured data to reestablish the welding residual stress. And based on the parallel computation of high-performance server, considering the effect of weld remelting and back-gouging during multi-pass welding process, the welding residual stress is predicted by using efficient thermal elastic plastic finite element method (TEP FEM). Results show that longitudinal residual stress turned from tensile stress in welded vicinity into compressive stress in base metal and the maximum tensile stress is 269 MPa. The computed longitudinal residual stress and welding displacement through TEP FEM are identified with the experimental results. In addition, the back-gouging has an insignificant effect on the residual stress but increases the welding displacement of butt welded joint. The proposed TEP FEM can accurately predict the welding residual stress in welded joint and is also an effective method to control welding displacement.

Download or read book Numerical Simulation of Residual Stresses in Welding and Ultrasonic Impact Treatment Process written by Lanqing Tang and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Welding technology is considered as a reliable and efficient joining method, which has been widely used in almost all the industry departments. Detrimental factors induced by welding such as micro-cracks/flaws, tensile residual stresses, high stress concentration may degrade the mechanical and fatigue properties of weld joints. Ultrasonic impact treatment (UIT) is considered one of the most efficient post-weld treatment which could improve the fatigue performance of weld joints. In this study, the effect of the UIT on residual stress distribution of 304L weld joints was particularly investigated. FE analysis simulation and the XRD experiment were performed to predict and measure residual stresses of both as-welded and the UIT-treated joints. Compared results show that simulated stresses are in good agreement with the experimental results along various paths, confirming the validity of welding model. The UIT introduces a compressive residual stress layer with depth between 2 and 3 mm near the impacting surface of weld joint.

Download or read book Analyses of the Temperature Residual Stress and Distortion Distributions Created in Type 304 Stainless Steel Weldment by an Automatic GTA Welding Process Using a Novel Weaving Weld Pattern written by Henry Shiu-Hung Chu and published by . This book was released on 1996 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Weld Residual Stress Finite Element Analysis Validation written by Michael Lee Benson and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Residual Stresses in Weld Overlay Tubes written by and published by . This book was released on 1997 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual stresses and strains in a tube with circumferential weld overlay were analyzed by the finite element (FE) method. The objective of this work was to develop and verify a FE model, to determine the magnitude and distribution of residual stresses in the weld overlay tube, and to evaluate the significance of two contributing factors to residual stress: (1) difference in material properties between tube and weld material, and (2) thermal gradients in the weld. An axisymmetric FE model was developed to simulate the circumferential two-layer welding process of alloy 625 overlay on SA210 tube. The first layer was modeled as a gas metal arc welding process with filler metal, whereas the autogenous gas tungsten arc welding process was modeled for the second layer. Neutron diffraction technique was used to experimentally determine residual elastic strains in the weld overlay tube. Comparison with the FE results shows overall good agreement. Both the experimental and FE results show high compressive stresses at the inside tube surface and high tensile stresses in the weld overlay. This suggests that weld overlay may be used to relieve tensile or produce compressive stresses at the inside tube surface, which is significant for applications where crack initiation is found at the root pass of the joining weld.

Download or read book Evaluation of Residual Stresses and Their Influence on Distortion in the Decoiling and Welding Processes written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis of de-coiling process is provided. The expression for equilibrium of internal stresses within de-coiled plate during welding was established. First simulations of the de-coiling process have been prepared using Finite Element Modeling technique. Experimental verification of numerical results has been performed. The experimental results are in very good agreement with the numerical results. More insight into the changes of the sample material during deformation was achieved by careful microstructural examination. The microhardness measurements were proposed as a new and fast method of indicating the position of the neutral plane within de-coiled plate. Based on literature review and results of performed analysis a set of general rules for assembling a large structure by welding from de-coiled plates was proposed. Based on that set it will be possible to predict de-coiled plate distortion during welding.

Download or read book Analysis of Welding induced Residual Stresses with the ADINA System written by and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Welding-induced residual stresses analysis procedure (WIRSAP), based on ADINA system of nonlinear finite element software, is described and results of several WIRSAP analyses are discussed. Several 2D axisymmetric WIRSAP analyses were performed for pipe girth welds and for several multi-pass girth-like welds attaching small nozzles to large, thick-walled pressure vessels. The analytical methodology follows closely Rybicki et al, enhanced by several specialized modeling techniques available in ADINA. The element birth option is used to simulate the addition of weld metal, and the mixed pressure/ displacement element formulation is used, in conjunction with temperature-dependent bi-linear plasticity material model. Some of the welds analyzed involve backing rings, which were subsequently 'machined off' via use of the element death option. The auto-time-stepping algorithm and matrix update iteration scheme are used in structural solutions. WIRSAP involves, a pass-by-pass analysis of uncoupled thermal and structural problems, but some analyses have been performed with an ''enveloping'' technique for grouping several weld passes together. The analyses are all 2D, but most are large problems and pose challenge to software and hardware. Operations are performed on a network of Silicon Graphics workstations, and ADINA and ADINA-T are executed on a 64 MW, eight-processor CRAY YIMP. Nominally 50 solution steps are utilized for each weld pass and weld joints involving as many as 31 individual weld passes analyzed on a pass-by-pass basis. Results from several WIRSAP analyses are discussed, and potential use of WIRSAP in a hypothetic attachment weld design optimization study is illustrated.

Download or read book Welding Residual Stresses and Distortion written by Dieter Radaj and published by . This book was released on 2003 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title deals with the computational simulation of temperature fields, residual stresses and distortion occuring during and after welding. Computational simulation is understood to be the reduction of the typical welding phenomena just mentionaed to physical models, and their mathematical representation in the form of computer programs.

Download or read book Finite Element Analysis written by David Moratal and published by IntechOpen. This book was released on 2010-08-17 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finite element analysis is an engineering method for the numerical analysis of complex structures. This book provides a bird's eye view on this very broad matter through 27 original and innovative research studies exhibiting various investigation directions. Through its chapters the reader will have access to works related to Biomedical Engineering, Materials Engineering, Process Analysis and Civil Engineering. The text is addressed not only to researchers, but also to professional engineers, engineering lecturers and students seeking to gain a better understanding of where Finite Element Analysis stands today.

Download or read book Fatigue Strength Reduction and Stress Concentration Factors for Welds in Pressure Vessels and Piping written by C. E. Jaske and published by . This book was released on 1998-06-01 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Report 1: Interpretive Review of Weld Fatigue-Strength-Reduction and Stress-Concentration Factors - Report 2: Fatigue-Strength-Reduction Factors for Welds Based on NDE