Download or read book Prediction of Fatigue Crack Growth Behavior in Fillet Welded Joints written by L. Tsai Chon and published by . This book was released on 1987 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Fatigue Crack Growth in Load and Non load carrying Fillet Welded Joints written by Mubashar Ahmad and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue is one of the major causes of failure in cyclically loaded structures such as, bridges, locomotive parts, rotating machinery components, etc. Welded structures are common in ship building. These welded structures are subjected to fluctuating loads in offshore environment, which requires proper attention for fatigue failure in the design phase of such structures. Although, lab tests can be conducted for concerned materials under controlled environmental conditions, but it is a cost and time intensive approach, and is not always possible. A number of assessments have been carried out over the years for a number of common structural configurations to standardize the design for fatigue and make it less cost-intensive. However, the amount of established standards is still very small relative to the number of possible design configurations. Hence, there is a constant need for numerical models which aim at estimating the fatigue life without the need for tests to be conducted. Crack Propagation is one of the established numerical approaches used for assessing remaining fatigue life of structures which are already in service. This approach is based on the assumption of an initial crack already existing in the structure, and consequently, the remaining fatigue life is considered to be dominated by crack propagation stage. The same can be considered true for welded structures, where weld imperfections and weld gaps act as micro-cracks and the service life of such structures can be considered to be dominated by crack growth stage. This study aims at evaluating the ability of crack propagation approach to predict the fatigue life of fillet welded joints. For this purpose, a numerical simulation tool called Franc2D is used to calculate the stress intensity factors (SIF) from 2D models. These values along with other factors are used as inputs for Paris and Erdogan Law to predict the fatigue life of load carrying and non-load carrying fillet welds. These results are then compared to the lab test results and the conclusions are drawn.

Download or read book Fracture Mechanics Analysis of the Fatigue Behavior of a Fillet Welded Joint written by S. J. Maddox and published by . This book was released on 1973 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The existence of a simple relationship between rate of crack propagation and range of stress intensity factor provides a method of calculating the fatigue strength of welded joints containing cracks or crack-like defects.

Download or read book Fatigue Crack Growth in a Fillet Welded Joint written by I. F. C. Smith and published by . This book was released on 1982 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Propagation in Aluminum Zinc Magnesium Alloy Fillet Welded Joints written by SJ. Maddox and published by . This book was released on 1978 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fatigue behavior of aluminum-zinc-magnesium (Al-Zn-Mg) alloy fillet-welded joints was analyzed in fracture mechanics terms. Basic crack propagation data were obtained with -2 ? R ? + 0.5 and correlated using formulas in the literature and, more successfully, in terms of ?Keff, based on the results of crack closure experiments. The form of the da/dN versus ?K relationship was influenced by the specimen geometry. A fracture mechanics analysis of the fatigue life of Al-Zn-Mg alloy fillet welds based on the da/dN versus ?Keff relationship indicated that the weld toe was less severe from the fatigue viewpoint than the same region in a steel fillet weld. This was compatible with the fact that metallurgical examination of Al-Zn-Mg alloy fillet welds has failed to reveal toe defects similar in magnitude to those which act as fatigue crack initiators at the toes of steel fillet welds. The analysis showed that the fatigue life obtained from the Al-Zn-Mg alloy weld could be predicted on the basis that defects only one tenth the size of those observed in steel were present. Fatigue failure from the weld root in a cruciform joint was also analyzed and the optimum weld design, which gives an equal chance of failure from the root and toe, was determined. The analysis was supported by fatigue test results. Comparison with results obtained for steel added confirmation to the finding that if toe defects are present in Al-Zn-Mg alloy welds, they are smaller than those in steel.

Download or read book Prediction of Fatigue Crack Near threshold Censored Regressions with Run out Data written by Yasser Alansary and published by . This book was released on 2014 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discussion is divided into two types of prediction. In the first type statistical models for fatigue life prediction for welded joints are discussed and fitted to experimental data for fillet-welded steel joints where cracks emanate from the weld toe. The models are based on an S-N approach where the number of cycles N to failure is assumed to be directly correlated to the applied nominal stress range [Delta]S. The models assume the existence of a fatigue limit given as a stress range below which no failure will take place. Emphasis is laid on the modeling of the fatigue life close to this limit where the service stresses for welded details often occur. Experimental data in this stress regime are sparse and do not fit the knee point of the conventional bi-linear S-N curve found in design rules and specifications. Therefore, an alternative model where both the fatigue life and the fatigue limit are simultaneously treated as random variables is investigated. The model parameters for this random fatigue-limit model (RFLM) are determined by the maximum likelihood method, and confidence intervals are obtained by the profile likelihood method. The advantage of the model is that it takes into consideration the variation in fatigue limit found from specimen to specimen and that run-out results are easily included. The median S-N curve obtained from the model coincides with the conventional bi-linear curves in the high stress regime (stress ranges higher than 110 MPa), but predicts longer lives as the stress range decreases below 100 MPa. The model gives a nonlinear S-N curve for a log-log scale in the fatigue-limit area; the fatigue life is gradually increasing and is approaching a horizontal line asymptotically instead of the abrupt knee point of the bilinear curve. The nonlinear curve is more in accordance with experimental data. At stress ranges below 100 MPa, the predicted fatigue lives are between 2 to 10 times longer than predictions made by the bilinear Category E curve in AISC Steel Construction Manual. The conclusion is that the rule-based S-N curves may be un-conservative in the stress regime where service stresses frequently occur. A more correct statistical model based on a random fatigue-limit model results in S-N curves that give decreased dimensions for a given fatigue design factor under constant amplitude loading. The second type of prediction is required if inspection is to be carried out in a damage tolerance approach. In this case fatigue process in fillet welded joints is discussed and modeled. As a first approximation, a pure fracture mechanics model was employed to describe the entire fatigue process. The model is calibrated to fit the crack growth measurements obtained from extensive testing on fillet weld joints where cracks emanate from the weld toes. Emphasis is laid on the choice of growth parameters in conjunction with a fictitious initial crack size distribution in order to obtain both reliable crack growth histories and predictions of the entire fatigue life. The model has its shortcomings in describing the damage evolution at low stress ranges due to the presence of a significant crack development period in this stress regime. As an alternative to the fracture mechanics model, a two-phase model (TPM) for the fatigue process was developed and calibrated.

Download or read book Peridynamic Analysis of Fatigue Crack Growth in Fillet Welded Joints written by KyuTack Hong and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue assessment is one of the significant factors to be considered for a design life of structure and estimation of structural reliability during operation. Especially, for welded structures, various welding effects, such as stress concentration, residual stresses, weld geometry and weld quality, make the structure more vulnerable to fatigue failures. This requires more effective approaches for estimating fatigue performances of welded structures.Existing classical methods to predict the crack propagation under cyclic loadings have some difficulties in treating complicated patterns of crack growth. A peridynamic theory, however, has powerful advantage on discontinuities. A peridynamic fatigue model, which is a bond damage model of remaining life, is used to demonstrate two phases of fatigue failure, crack nucleation and crack growth. Two types of numerical tests are conducted to validate the peridynamic fatigue model. One is tensile test for the phase of crack nucleation and the other is compact tension test for the phase of crack growth. All results from numerical tests are compared with experimental test data to validate the peridynamic fatigue model.After validation of peridynamic fatigue model, numerical tests with peridynamic fatigue model are performed to investigate a weld effect of the length of unwelded zone on the fatigue performance of load-carrying fillet welded joint. Numerical results of fatigue performance and path of fatigue crack growth are compared with existing experimental data.In this thesis, the peridynamic fatigue model is validated by two different fatigue tests which are uniaxial tension-compression tests for the crack nucleation and ASTM E647 standard compact tests for the crack growth. After validation, the fatigue performance of the fillet welded joint is estimated with respect to the length of unwelded zone by simulating the fatigue crack growth under cyclic load conditions with the peridynamic fatigue model.

Download or read book Design and Analysis of Fatigue Resistant Welded Structures written by Dieter Radaj and published by Woodhead Publishing. This book was released on 1990-01-03 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: An English version of a sucessful German book. Both traditional and modern concepts are described.

Download or read book International Conference on Residual Stresses written by G. Beck and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1043 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual stresses are always introduced in materials when they are produced, or when they undergo non-uniform plastic deformation during use. The circumstances that can cause residual stresses are therefore numerous. Residual stresses exist in all materials and, depending on their distribution, can playa beneficial role (for example, compressive surface stress) or have a catastrophic effect, especially on fatigue behaviour and corrosion properties. The subject of residual stresses took form around 1970 with the development of methods to measure macroscopic deformations during the machining of materials or on an atomic scale by X-ray diffraction. These techniques have made considerable progress in the last 20 years. The meetings organized in several countries (Germany, France, Japan, etc. ) have largely contributed to this progress, aided by the numerous exchanges of information and knowledge to which they have given rise. Studies of the formation of residual stresses began more slowly, but have progressed with the emergence of increasingly realistic models of materials behaviour and with access to ever more powerful codes for numerical calculations. Two successive meetings for discussing this topic have been held in Europe. The first, held in 1982 in Nancy (France), consisted of 30 participants from 5 countries. The second was held in Linkoping (Sweden) in 1984, with 80 participants of 16 nationalities. It was decided to hold a first International Conference, ICRS, to address all aspects of the problem. Held in 1986 in Garmisch-Partenkirschen (FRG), it was an assembly of neady 300 participants from 21 countries.

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.

Download or read book Guide to Methods for Assessing the Acceptability of Flaws in Metallic Structures written by British Standards Institute Staff and published by . This book was released on 1913-12-31 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structures, Metals, Welded joints, Welding, Fusion welding, Structural systems, Components, Flaws, Defects, Structural steels, Ferritic steels, Austenitic steels, Steels, Aluminium alloys, Approval testing, Non-destructive testing, Stress analysis, Structural design, Cracking, Fracture, Failure (mechanical), Inclusions, Porosity, Tensile testing, Thermal testing, Leak tests, Load measurement, Fatigue testing, Classification systems, Strength of materials, Creep, Joints, Tubular shape, Stress corrosion, Corrosion, Impact testing, Schematic representation, Graphic representation, Dimensions, Mathematical calculations, Bibliography, Symbols

Download or read book The Effect of Plate Thickness on the Fatigue Strength of Fillet Welded Joints written by Stephen John Maddox and published by . This book was released on 1987 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Assessment of Welded Joints by Local Approaches written by Dieter Radaj and published by Woodhead Publishing. This book was released on 2006-10-30 with total page 661 pages. Available in PDF, EPUB and Kindle. Book excerpt: Local approaches to fatigue assessment are used to predict the structural durability of welded joints, to optimise their design and to evaluate unforeseen joint failures. This standard work provides a systematic survey of the principles and practical applications of the various methods. It covers the hot spot structural stress approach to fatigue in general, the notch stress and notch strain approach to crack initiation and the fracture mechanics approach to crack propagation. Seam-welded and spot-welded joints in structural steels and aluminium alloys are also considered.This completely reworked second edition takes into account the tremendous progress in understanding and applying local approaches which has been achieved in the last decade. It is a standard reference for designers, structural analysts and testing engineers who are responsible for the fatigue-resistant in-service behaviour of welded structures. - Completely reworked second edition of a standard work providing a systematic survey of the principles and practical applications of the various methods - Covers the hot spot structural stress approach to fatigue in general, the notch stress and notch strain approach to crack initiation and the fracture mechanics approach to crack propagation. - Written by a distinguished team of authors

Download or read book Fatigue Durability and Fracture Mechanics written by S. Seetharamu and published by Springer Nature. This book was released on 2020-10-01 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents selected papers presented during Fatigue Durability India 2019. The contents of this volume discuss advances in the field of fatigue, durability, and fracture, and cover mechanical failure and its applications. The chapters cover a wide spectrum of topics, including design, engineering, testing and computational evaluation of the components or systems for fatigue, durability, and fracture mechanics. The contents of this book will appeal not only to academic researchers, but also to design engineers, failure analysts, maintenance engineers, certification personnel, and R&D professionals involved in a wide variety of industries.

Download or read book Fatigue Life and Crack Growth Prediction Methodology written by J. C. Newman (Jr) and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Propagation Life Predictions for Butt and Fillet Welds written by Frederick VanBuren Lawrence and published by . This book was released on 1974 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Life Prediction of Welded Components Based on Fracture Mechanics written by MH. El Haddad and published by . This book was released on 1980 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: An elastic-plastic fracture mechanics solution for fatigue cracks initiating from weld toes is introduced that admits plasticity by replacing the conventional stress term with a strain term. It accounts for the propagation of very short cracks by the introduction of an effective crack length equal to the actual length increased by an amount l0, where l0 is a constant characteristic of the material and material condition. Consideration is also given to the effect of mean stress and crack front shape on an intensity factor derived from this solution. Crack growth results for cracks in both elastic and plastic strain fields of welded specimens, when interpreted in terms of the intensity factor, show excellent agreement with elastic long crack data. This intensity factor, when combined with a propagation model that includes all stages of crack growth, also successfully predicts the entire life of butt- and fillet-welded specimens for two steels. The threshold stress corresponding to the failure of butt-welded specimens is equal to the smooth specimen fatigue limit stress divided by the elastic stress concentration factor. However, for fillet welds, the stress level corresponding to failure is higher than the fatigue limit stress divided by the elastic stress concentration factor. At stresses between these two stress levels, cracks start at fillet-weld toes but do not propagate to failure.