Download or read book Probabilistic Description of Fatigue Crack Growth Under Constant and Variable Amplitude Loading written by H. Ghonem and published by . This book was released on 1989 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is concerned with the description of the development and application of a stochastic crack growth model. It is built as a discontinuous Markov process and is inhomogeneous with respect to the number of cycles required for the crack to reach a specified crack length. The model is then used to describe the evolution of the crack length in terms of growth curves, each of whose points possess equal probability of advancing from one position to another forward position. The validity of the model is established by applying it to constant-as well as to variable amplitude loading. In those applications the theoretical constant probability crack growth curves generated by the model compared to those experimentally obtained using Al 7075-T6 and Al 2024-T3 material for constant-amplitude loading while Ti-6Al-4V was used in single overload application. Results of these comparisons indicate the ability of the proposed model when fitted with parameters whose values can be obtained from a limited numbers of experimental tests, to predict the crack growth statistics under different loading conditions. Keywords: Crack; Overload; Stochastic process; Retardation; Titanium alloy; Aluminum alloys; Vanadium. (kt).
Download or read book Study of Probabilistic Fatigue Crack Growth and Associated Scatter Under Constant and Variable Amplitude Loading Spectrum written by Hamouda Ghonem and published by . This book was released on 1987 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the program's second year research work was to examine the validity of the constant probability crack growth model while refining the transition intensity parameter. This work has been completed, thus leading to a crack growth rate equation with an explicit probability term. Furthermore, work extending the applicability of the model to variable loading required the determination of the delay-time associated with a single overload. An experimental test program was carried out on a titanium alloy using a potential drop technique to record crack length increments as function of overload characteristics. This program has been completed and results will be incorporated into the basic stochastic model.
Download or read book Fatigue Crack Growth Under Variable Amplitude Loading written by J. Petit and published by Springer. This book was released on 1988-12-31 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth written by Hans Albert Richard and published by Springer. This book was released on 2016-06-13 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a concise introduction to fatigue crack growth, based on practical examples. It discusses the essential concepts of fracture mechanics, fatigue crack growth under constant and variable amplitude loading and the determination of the fracture-mechanical material parameters. The book also introduces the analytical and numerical simulation of fatigue crack growth as well as crack initiation. It concludes with a detailed description of several practical case studies and some exercises. The target group includes graduate students, researchers at universities and practicing engineers.
Download or read book Methods and Models for Predicting Fatigue Crack Growth Under Random Loading written by and published by ASTM International. This book was released on with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth under Spectrum Loads written by and published by ASTM International. This book was released on 1976 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Prediction Methods for Variable Amplitude Loading written by and published by . This book was released on 1988 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Considerable data on fatigue properties of materials under constant amplitude loading is available in the literature under the forms representative of the different aspects of the fatigue phenomenon. To employ these data, the design engineer must adapt it to the particular service conditions that he is concerned with. The stress vs. life or S-N curve is largely related to the fatigue initiation behaviour of materials and defines the endurance limit which is used for design. The strain-life curve is of more recent origin and relates the elastic and plastic strain amplitudes to the initiation life. Fatigue propagation data are presented on a crack growth rate vs. stress intensity factor range diagram.
Download or read book Prediction of Fatigue crack Growth Under Variableamplitude and Spectrum Loading Using a Closure Model written by and published by . This book was released on 1981 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Predictions of Surface Cracks Under Constant amplitude and Variable amplitude Loading written by Ichsan S. Putra and published by . This book was released on 1994 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Random Fatigue written by K. Sobczyk and published by Academic Press. This book was released on 2012-12-02 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many years fatigue has been a significant and difficult problem for engineers, especially for those who design structures such as aircraft, bridges, pressure vessels, and cranes. Fatigue of engineering materials is commonly regarded as an important deterioration process and a principal mode of failure for various structural and mechanical systems. This book presents a unified approach to stochastic modeling of the fatigue phenomenon, particularly the fatigue crack growth process. The main approaches to construction of these stochastic models are presented to show their methodological consistency and potential usefulness in engineering practice. The analyses contained in this work should also inspire the development of new approaches for designing and performing fatigue experiments.
Download or read book Fatigue Crack Growth Preductions of Surface Cracks Under Constant amplitude and Variable amplitude Loading written by Ichsan S. Putra and published by . This book was released on 1994 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Life Prediction Based on the Advanced Fatigue Crack Growth Model and the Monte Carlo Simulation Method written by Sergey Bogdanov and published by . This book was released on 2014 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well-known that loss of the structural stability due to propagation of the dominant crack is one of the main sources of fatigue failures. Therefore, computationally feasible fatigue crack growth model is essential for advanced fatigue life analysis. Appropriate model should be able to calculate the time required for crack to grow: from the initial crack of any size to the final critical length; in any structure; under applied variable loading. The UniGrow two-parameter total driving force was proposed ten years ago. Since then, the fatigue crack growth model based on it, was enhanced with a set of memory rules and resulted in a sophisticated fatigue crack growth software package which was extensively validated on the basis of available experimental data. Nevertheless, in its previous form the UniGrow model had several serious limitations: it was not able to model the fatigue crack growth under plane-strain conditions; the Neuber rule was the only method used for elastic-plastic stress-strain analysis; the fatigue crack growth prediction was limited to macro-cracks and the variability of the material response to cyclic loading has not been considered. In addition to these shortcomings, there were no preferred method for estimation of the material block size , which is one of the main parameters required for the analysis. Therefore, further modeling and validation of the UniGrow concept were required before it could be coupled with the "Monte-Carlo" simulation method. The main research goal pursued in this work was to improve and remove limitations of the existing fatigue crack growth model and to combine this model with "Monte-Carlo" simulations. Such combination enables the assessment of the reliability of predicted fatigue lives. Thus, the result of this work is an extensive probabilistic fatigue crack growth model, which is able to perform the analysis of structures in the plane-strain or plane-stress condition. Comprehensive set of the fatigue crack growth data for aluminum and steel alloys generated under the constant and variable amplitude loading was used for the validation.
Download or read book Fatigue Analyses Under Constant and Variable amplitude Loading Using Small crack Theory written by J. C. Newman and published by . This book was released on 1999 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies on the growth of small cracks have led to the observation that fatigue life of many engineering materials is primarily "crack growth" from micro-structural features, such as inclusion particles, voids, slip-bands or from manufacturing defects. This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using "small-crack theory" under various loading conditions. Constraint factors, to account for three-dimensional effects, were selected to correlate large-crack growth rate data as a function of the effective stress-intensity factor range ([delta]Keff) under constraint-amplitude loading. Modifications to the [delta]Keff-rate relations in the near-threshold regime were needed to fit measured small-crack growth rate behavior. The model was then used to calculate small- and large-crack growth rates, and to predict total fatigue specimens for most of the materials analyzed. Results from the tests and analyses agreed well.
Download or read book Stochastic Crack Propagation with Applications to Durability and Damage Tolerance Analyses written by J. N. Yang and published by . This book was released on 1985 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various stochastic models for fatigue crack propagation under either constant amplitude or spectrum loadings have been investigated. These models are based on the assumption that the crack growth rate is a lognormal random process, including the general lognormal random process, lognormal white noise process, lognormal random variable, and second moment approximations, such as Weibull, gamma, lognormal and Gaussian closure approximations. Extensive experimental data have been used for the correlation study with various stochastic models. These include fastener hole specimens under fighter or bomber spectrum laodings and center-cracked specimens under constant amplitude loads. The data sets for the fastener hole specimens cover adequately different loading conditions, environments, load transfers and crack size range. It is shown that the white noise process is definitely not a valid model for fatigue crack propagation.
Download or read book Fatigue Crack Growth Under Variable Amplitude Loading written by Société Française de Métallurgie and published by . This book was released on 1988 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling High Crack Growth Rates Under Variable Amplitude Loading written by AU. de Koning and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A two-component crack growth model has been developed to treat fatigue crack growth under constant and variable amplitude loading. The model is based on a concept introduced by Paris which relates the crack growth to the instantaneous plastic zone size ahead of the crack-tip. This concept was applied to describe crack growth in the presence of cyclic and primary plastic flow. The model was formulated on an incremental basis in which a particular component of the model is integrated about a discrete portion of the load excursion. The model includes the effects of cyclic and monotonic crack growths and crack closure. The results for fatigue crack growth data reported in the literature for multiple overload and severe flight sequences are compared with the model predictions. The model was shown to describe accelerated crack growth behavior typically observed during these sequences. Acceleration effects occur in the presence of primary plastic flow which is related to the ductile tearing mechanism and is not dependent upon crack closure or other load-history effects. Moreover, the model describes the phenomenological variation of the acceleration effects over such sequences. The predicted crack growth agrees well with the experimental data.
