Download or read book Influence of Residual Stress on Fatigue Failure of Welded Joints written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation makes an effort to understand the influence of residual stresses on the fatigue failure of butt- and socket-welded piping joints. In order to achieve this goal, this study develops experimental fatigue failure data and a numerical scheme for the analysis of these data. A set of low-cycle fatigue tests of welded piping joints in the cantilever setup is conducted. A new observation made in these tests is that the recorded strains near the weld toe ratchet continuously, which results in the initiation of fatigue crack(s). Comparison of these ratcheting responses with those from the cyclic pipe bending and material ratcheting experiments indicates that the residual stresses at the welded joints may not relax to zero after a few inelastic cycles, as assumed in the fatigue design methods. This observation is further supported by the symmetric strain response (no ratcheting) at the mid-pipe length, which is located away from the welded joint. At this location, there are no residual stresses to induce ratcheting. It is also observed that the fatigue cracks in all experiments occurred at the weld toe location where the ratcheting strain is the largest. This indicates that the fatigue life of materials is reduced in the presence of ratcheting. There are several observations made in the tests that need further exploration. Ratcheting in the tests occurs under displacement-controlled loading cycles, which seems kinematically inadmissible. The recorded load responses demonstrate cyclic softening for stainless steel, which is known as a cyclically hardening material. It is also observed that the socket-weld which is fabricated using the quarter-circumferential welding method has a longer fatigue life than the one which is fabricated using the full-circumferential welding method. Also, the socket-weld with four weld passes has longer fatigue life than the socket-weld with three weld passes. This study with its limited time and resource could not explore these iss.

Download or read book Influence of Residual Stress on Fatigue Failure of Welded Joints written by Xiangyang LU and published by . This book was released on 2003 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fracture and Fatigue of Welded Joints and Structures written by K Macdonald and published by Elsevier. This book was released on 2011-04-19 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: The failure of any welded joint is at best inconvenient and at worst can lead to catastrophic accidents. Fracture and fatigue of welded joints and structures analyses the processes and causes of fracture and fatigue, focusing on how the failure of welded joints and structures can be predicted and minimised in the design process.Part one concentrates on analysing fracture of welded joints and structures, with chapters on constraint-based fracture mechanics for predicting joint failure, fracture assessment methods and the use of fracture mechanics in the fatigue analysis of welded joints. In part two, the emphasis shifts to fatigue, and chapters focus on a variety of aspects of fatigue analysis including assessment of local stresses in welded joints, fatigue design rules for welded structures, k-nodes for offshore structures and modelling residual stresses in predicting the service life of structures.With its distinguished editor and international team of contributors, Fracture and fatigue of welded joints and structures is an essential reference for mechanical, structural and welding engineers, as well as those in the academic sector with a research interest in the field. - Analyses the processes and causes of fracture and fatigue, focusing predicting and minimising the failure of welded joints in the design process - Assesses the fracture of welded joints and structure featuring constraint-based fracture mechanics for predicting joint failure - Explores specific considerations in fatigue analysis including the assessment of local stresses in welded joints and fatigue design rules for welded structures

Download or read book Influence of Residual Stress and Heat Affected Zone on Fatigue Failure of Welded Piping Joints written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT CHENG, PEI-YUAN. Influence of Residual Stress and Heat Affected Zone on Fatigue Failure of Welded Piping Joints. (Under the direction of Dr. Tasnim Hassan.) In recent decades, some unexpected fatigue failure occurred in welded joint of metal structures under cyclic loading. In many cases, the cause for the failure could not be detected. A study at NC State University revealed that welding procedure could be one of the factors that was not appropriately considered in current design methodologies. The welding procedure can influence the strain response near weld toe in two ways: one is by generating residual stress, and the other is changing material properties in the heat affected zone (HAZ). It was the primary objective in this investigation to determine the influence of these two factors on strain response by conducting experiments and performing numerical simulations of welded piping joints. On experimental study a series of residual stress data were measured, using x-ray and neutron diffraction techniques, for welded piping joints. The measured results revealed that the initial maximum compressive residual stress of stainless steel piping joints is higher than the yield stress of base metal. Moreover, the axial residual stresses of stainless steel piping joints are mostly relaxed after 5 cycles. The change of mechanical material properties due to high temperature exposure was studied by conducting experiments on tubular specimens. It was obtained that some mechanical material properties changed after subjecting to high temperature cycles, and the changed material was correlated to the peak temperatures. A modified thermo-mechanical material heterogeneity model was then developed to improve the initial residual stress simulation at the weld toe. The heterogeneous material properties coupled with the Chaboche model were used for subsequent fatigue response simulation. Quarter-point elements were applied at the stress concentration locations. The analysis r.

Download or read book Cumulative Damage of Welded Joints written by T R Gurney and published by Woodhead Publishing. This book was released on 2006-08-25 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue is a mechanism of failure which involves the formation and growth of cracks under the action of repeated stresses. Ultimately, a crack may propagate to such an extent that total fracture of the member may occur. To avoid fatigue it is essential to design the structure with inherent fatigue strength. However, fatigue strength for variable amplitude loading is not a constant material property and any calculations are necessarily built on a number of assumptions. Cumulative damage of welded joints explores the wealth of research in this important field and its implications for the design and manufacture of welded components.After an Introduction, chapter two introduces the constant amplitude database, which contains results obtained in test conditions and which forms the basis of the basic S-N curves for various types of joint. Chapter three discusses the influence of residual stresses which can have a marked effect on fatigue behaviour. Chapter four explores variable amplitude loading and the problem of how information from laboratory tests, obtained under constant amplitude conditions, can be applied to the design of structures for service conditions. This problem is further investigated in the next chapter which is devoted to two and three level load testing. Chapters six, seven and eight look at the influence that the variety of variable loading spectra can have on fatigue strength, whether narrow or wide band loading or cycles of small stress range. Taking all of this knowledge, chapter nine discusses structure designs.Cumulative damage of welded joints is a comprehensive source of invaluable information for welding engineers, supervisors, inspection personnel and designers. It will also be of great interest for academics working in the fields of structural and mechanical engineering. - Covers the wealth of research in the field of fatigue strength and its role in the design and manufacture of welded components - Invaluable reference source for welding engineers, supervisors, inspection personnel and designers

Download or read book Influence of Residual Stress and Heat Affected Zone on Fatigue Failure of Welded Piping Joints written by Pei-Yuan Cheng and published by . This book was released on 2009 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: FE simulation, residual stress, weld, piping joint.

Download or read book Fatigue Testing of Weldments written by D. W. Hoeppner and published by ASTM International. This book was released on 1978 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Welding Deformation and Residual Stress Prevention written by Ninshu Ma and published by Elsevier. This book was released on 2012-04-26 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: Generally, welding produces welding deformation and residual stress in the products, which influences the quality and performance of the products. Although many engineers and researchers have made great effort how to control these incidents, they have still remained unresolved. Welding Deformation and Residual Stress Prevention provides a unique computational approach to the prediction of the effects of deformation and residual stress on materials. The goal is to provide engineers and designers with the ability to create their own computational system for predicting and possibly avoiding the problem altogether. - The basic theories including "theory of elastic-plastic analysis" and "inherent strain theory" , and analysis procedures are described using a simple three-bar model - Online simulation software to perform basic analysis on welding mechanics - Examples of strategic methods and procedures are illustrated to have solved various welding-related problems encountered in the process of construction - Appendices present data bases for welding residual stresses, temperature dependent material properties, etc.

Download or read book Residual Stress Analysis on Welded Joints by Means of Numerical Simulation and Experiments written by Paolo Ferro and published by BoD – Books on Demand. This book was released on 2018-05-16 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to quantify residual stresses induced by welding processes through experimentation or numerical simulation has become, today more than ever, of strategic importance in the context of their application to advanced design. This is an ongoing challenge that commenced many years ago. Recent design criteria endeavour to quantify the effect of residual stresses on fatigue strength of welded joints to allow a more efficient use of materials and a greater reliability of welded structures. The aim of the present book is contributing to these aspects of design through a collection of case-studies that illustrate both standard and advanced experimental and numerical methodologies used to assess the residual stress field in welded joints. The work is intended to be of assistance to designers, industrial engineers and academics who want to deepen their knowledge of this challenging topic.

Download or read book Influence of Residual Stress on the Initiation of Fatigue Cracks at Welded Piping Joints written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue failures of small bore piping systems have historically occurred in nuclear power plants, resulting in unanticipated plant downtime and substantial financial loss. These failures have been reported with increasing frequency over the past 20 years and have motivated the research described in this thesis. Recent research at North Carolina State University (NCSU) pointed to the strain ratcheting response of the welded joint as a probable reason for fatigue failure and indicated that welding residual stresses might be responsible for inducing this strain ratcheting response. It was the primary objective in this investigation to determine what happens to residual stresses at the welded piping joint under the application of low-cycle fatigue loading and to understand how residual stresses induce strain ratcheting and thus affect the fatigue life of the welded joint. In order to achieve stated objectives, a systematic set of residual stress measurements and low-cycle fatigue tests was conducted. Initial residual stresses near the weld toe of six welded piping specimens were measured using the technique of x-ray diffraction. The specimens were then loaded in low-cycle fatigue to intermediate points in their fatigue lives and residual stresses were measured again. Strain response data near the weld toe was gathered throughout specimen fatigue life. Residual stress data and recorded strain responses in fatigue prompted conclusions concerning the role of residual stresses in inducing strain ratcheting which were verified by additional material level experiments. Initial residual stress measurements obtained from the welded specimens revealed that residual stresses near the weld toe--the location of fatigue crack initiation and final failure--were compressive in the overwhelming majority of measurement cases. It is widely accepted that compressive residual stresses are beneficial in fatigue. However, in this set of experiments, it was observed that compressive.

Download or read book Springer Handbook of Experimental Solid Mechanics written by William N. Sharpe, Jr. and published by Springer Science & Business Media. This book was released on 2008-12-04 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Springer Handbook of Experimental Solid Mechanics documents both the traditional techniques as well as the new methods for experimental studies of materials, components, and structures. The emergence of new materials and new disciplines, together with the escalating use of on- and off-line computers for rapid data processing and the combined use of experimental and numerical techniques have greatly expanded the capabilities of experimental mechanics. New exciting topics are included on biological materials, MEMS and NEMS, nanoindentation, digital photomechanics, photoacoustic characterization, and atomic force microscopy in experimental solid mechanics. Presenting complete instructions to various areas of experimental solid mechanics, guidance to detailed expositions in important references, and a description of state-of-the-art applications in important technical areas, this thoroughly revised and updated edition is an excellent reference to a widespread academic, industrial, and professional engineering audience.

Download or read book Fatigue of Welded Structures written by Timothy Russell Gurney and published by CUP Archive. This book was released on 1979-12-20 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Strength of Welded Structures written by S J Maddox and published by Woodhead Publishing. This book was released on 1991-01-15 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition encompasses the latest research and particularly the recent standards. The text will be of value to welding engineers and designers, medium to large companies and technical libraries.

Download or read book Advances in Fatigue Science and Technology written by C. Moura Branco and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the edited version of lectures and selected research contributions presented at the NATO ADVANCED STUDY INSTITUTE on ADVANCES IN FATIGUE SCIENCE AND TECHNOLOGY. held in Alvor. Portugal, 4th to 15th of April 1988. and organized by CEMUL - Center of Mechanics and Materials of The Technical University of Lisbon. The Institute was attended by 101 participants, including 15 lecturers. from 14 countries. The participants were leading scientists and engineers from universities, research institutions and industry. and also Ph.D~ students. Some participants presented papers during the Institute reporting the state-of-art of their research projects. All the sessions wel'e very active and quite extensive discussions on scientific aspects took place during the Institute. The Advanced Study Institute provided a forum for interaction among eminent scientists and engineers. from different schools of thought and young researchers. The Institute addressed the foundations and current state of the art of essential aspects related to fatigue science and technology, namely: Short Cracks, Metallurgical Aspects, Environmental Fatigue, Threshold Behaviour, Notch Behaviour. Creep and Fatigue Interactions at High Temperature, Multiaxial Fatigue, Low Cycle Fatigue, Methodology of Fatigue Testing, Variable Amplitude Fatigue, Fatigue of Advanced Materials. Elastic-Plastic Fatigue, and several engineering applications such as welded joints, energy systems, offshore structures, automotive industry, machine and engine components. This book is organized in three parts: Part I: Fundamentals of Fatigue Part II: Engineering Applications Part III: Research Contributions The research contributions covered most of the areas referred above.

Download or read book IIW Recommendations On Methods for Improving the Fatigue Strength of Welded Joints written by P J Haagensen and published by Woodhead Publishing. This book was released on 2013-01-25 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The weld toe is a primary source of fatigue cracking because of the severity of the stress concentration it produces. Weld toe improvement can increase the fatigue strength of new structures significantly. It can also be used to repair or upgrade existing structures. However, in practice there have been wide variations in the actual improvements in fatigue strength achieved. Based on an extensive testing programme organised by the IIW, this report reviews the main methods for weld toe improvement to increase fatigue strength: burr grinding, TIG dressing and hammer and needle peening. The report provides specifications for the practical use of each method, including equipment, weld preparation and operation. It also offers guidance on inspection, quality control and training as well as assessments of fatigue strength and thickness effects possible with each technique. IIW recommendations on methods for improving the fatigue strength of welded joints will allow a more consistent use of these methods and more predictable increases in fatigue strength. Provides specifications for the practical use of each weld toe method, including equipment, weld preparation and operation Offers guidance on inspection, quality control and training, as well as assessments of fatigue strength and thickness effects possible with each technique This report will allow a more consistent use of these methods and more predictable increases in fatigue strength

Download or read book Residual Stress Effects in Fatigue written by J. F. Throop and published by ASTM International. This book was released on 1982 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Life Analyses of Welded Structures written by Tom Lassen and published by John Wiley & Sons. This book was released on 2013-03-01 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Avoiding or controlling fatigue damage is a major issue in the design and inspection of welded structures subjected to dynamic loading. Life predictions are usually used for safe life analysis, i.e. for verifying that it is very unlikely that fatigue damage will occur during the target service life of a structure. Damage tolerance analysis is used for predicting the behavior of a fatigue crack and for planning of in-service scheduled inspections. It should be a high probability that any cracks appearing are detected and repaired before they become critical. In both safe life analysis and the damage tolerance analysis there may be large uncertainties involved that have to be treated in a logical and consistent manner by stochastic modeling. This book focuses on fatigue life predictions and damage tolerance analysis of welded joints and is divided into three parts. The first part outlines the common practice used for safe life and damage tolerance analysis with reference to rules and regulations. The second part emphasises stochastic modeling and decision-making under uncertainty, while the final part is devoted to recent advances within fatigue research on welded joints. Industrial examples that are included are mainly dealing with offshore steel structures. Spreadsheets which accompany the book give the reader the possibility for hands-on experience of fatigue life predictions, crack growth analysis and inspection planning. As such, these different areas will be of use to engineers and researchers.