Download or read book Study of an On Line Crack Compliance Technique for Residual Stress Measurement Using 2D Finite Element Simulations of Fatigue Crack Growth written by S. Ismonov and published by . This book was released on 2012 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are several methods available to measure residual stress fields present within a structural component. Recently a new so called on-line crack compliance technique has been proposed, which is based on linear elastic fracture mechanics. This experimental method uses incremental crack mouth opening displacements measured during fatigue crack growth testing to generate information on the existing residual stresses along the crack line. The present study employs two dimensional (2D) plane stress finite element simulations of fatigue crack growth from a cold worked hole to investigate the performance of this technique. Using the simulation results, the stress intensity factors due to the residual stress field normalized by the maximum applied stress intensity factor KIrs/KImax were obtained from the online crack compliance method. For validation, the J-integral approach was used to calculate KIrs/KImax values from fatigue crack growth simulations in an elastic material. The two methods generated nearly identical results. Fatigue crack growth was also simulated in an elastic-plastic material. Even though the stress intensity factor is not the appropriate crack tip characterizing technique for elastic-plastic material conditions, it is still investigated here to approximate the actual testing conditions, where plastic deformation near the crack tip is unavoidable. The KIrs/KImax solutions are presented for different cold work levels and applied loadings. Results indicate that the agreement between the elastic and elastic-plastic crack growth solutions is dependent on the maximum applied loading level, as might be expected.
Download or read book Analysis of Fatigue Crack Growth and Residual Stress written by Shakhrukh Ismonov and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of this dissertation employs a three-dimensional elastic-plastic finite element model of straight-through crack growth to correlate four well-known methodologies characterizing fatigue crack closure. The compliance offset and the adjusted compliance ratio (ACR) are experimental methods, whereas the node displacement and the contact stress methods are numerical approaches. Evolutions of crack closure from all four methodologies are compared for a numerical model of a single edge-cracked tension specimen subjected to different levels of constant amplitude cyclic loading. In the second part, a detailed two dimensional stress analysis is conducted for a single pin-joint under plane stress conditions. This study investigates the influence of material nonlinearity, friction, and pre-existing residual stresses from cold-working process on the local radial and hoop stress levels around the pin-loaded hole. Next, the beneficial influence of cold working process is quantified by computing the Mode I stress intensity factors K[subscript I] for a single radial crack emanating from a side of a loaded hole. Two different loading configurations are considered: (a) an open hole in tension, (b) a pin-loaded hole. The stress intensity factors are computed using the J integral solutions and the weight functions specific to the crack configuration. The reductions in K[subscript I] values due to different levels of cold-working process are presented for a range of crack lengths. The final part of the research involves a numerical investigation of an on-line crack compliance technique that is used for experimental measurements of residual stress fields along the crack growth path. A finite rectangular sheet is considered with a single crack emanating from a side of a central hole. The residual stress field is introduced around the hole by cold-working simulation. As part of validation, the normalized residual stress intensity factors computed using the on-line crack compliance technique are compared with those from the J-integral approach for the case of elastic crack growth. The influence of crack tip plasticity on the performance of the on-line crack compliance technique is studied by comparing the solutions of the elastic and elastic-plastic crack growth models.
Download or read book The Influence of Residual Stress on Fatigue Crack Growth written by James E. LaRue and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses the analysis of fatigue crack growth in the presence of residual stresses to determine a suitable method for fatigue life predictions. In the research discussed herein, the prediction methodologies are compared to determine the most accurate prediction technique. Finite element analysis results are presented as well as laboratory test data. The validity of each methodology is addressed and future work is proposed.
Download or read book The Influence of Residual Stress on Fatigue Crack Growth written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses the analysis of fatigue crack growth in the presence of residual stresses to determine a suitable method for fatigue life predictions. In the research discussed herein, the prediction methodologies are compared to determine the most accurate prediction technique. Finite element analysis results are presented as well as laboratory test data. The validity of each methodology is addressed and future work is proposed.
Download or read book Mechanics of Fatigue Crack Closure written by Wolf Elber and published by ASTM International. This book was released on 1988 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 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 1973 with total page 1102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Measurement and Data Analysis written by S. J. Hudak and published by ASTM International. This book was released on 1981 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Fracture and Residual Stresses written by Sharif Rahman and published by . This book was released on 1998 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fifty-one technical papers from the July 1998 Conference are organized into six sections which discuss probabilistic fracture mechanics, fracture of welds, finite elements and constraint effects on fracture, failure prediction, residual stresses, and pipe fracture. They present novel analytical and
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 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 1989 with total page 1148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Engineering Index Annual written by and published by . This book was released on 1992 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.
Download or read book The Virtual Crack Closure Technique History Approach and Applications written by Ronald Krueger and published by . This book was released on 2002 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the virtual crack closure technique is presented. The approach used is discussed, the history summarized, and insight into its applications provided. Equations for two-dimensional quadrilateral elements with linear and quadratic shape functions are given. Formula for applying the technique in conjuction with three-dimensional solid elements as well as plate/shell elements are also provided. Necessary modifications for the use of the method with geometrically nonlinear finite element analysis and corrections required for elements at the crack tip with different lengths and widths are discussed. The problems associated with cracks or delaminations propagating between different materials are mentioned briefly, as well as a strategy to minimize these problems. Due to an increased interest in using a fracture mechanics based approach to assess the damage tolerance of composite structures in the design phase and during certification, the engineering problems selected as examples and given as references focus on the application of the technique to components made of composite materials.
Download or read book A Methodology for Partitioning Residual Stress Effects From Fatigue Crack Growth Rate Test Data written by M. James and published by . This book was released on 2016 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper described an improved fatigue crack growth rate (FCGR) material characterization process that partitioned residual stress effects from the material "true" FCGR behavior, leading to FCGR design curves that are free of residual stress bias. The material used in the program had high residual stress intentionally introduced. Two test methods from the literature were used to characterize the material: the adjusted compliance ratio (ACR) test method for closure correction, and the crack compliance test method for measuring the stress-intensity factor due to residual stress (Kres). Both test methods operated independently on compliance data collected during FCGR tests. Two independent data reduction methods were used to analyze the FCGR data. In the first, the closure corrected ACR data were combined with the Kres data using a power law relationship to normalize the curves into a residual stress free "master" curve, which was then transformed into a more traditional closure free ?Keff curve. In the second, the Kres data were used in a superposition approach along with a closure model to reduce the data directly to the closure free ?Keff curve. The two ?Keff curves were shown to be in good agreement. The closure model was also used to reintroduce the stress ratio effect to generate the familiar da/dN-?K family of design curves that were free of residual stress bias. Validation examples were included where curves for the material with high residual stress were compared with data from similar material that had minimal residual stress, and those results were in good agreement. A summary of fatigue crack growth life predictions was also included to show that when residual stress effects are removed from FCGR characterization data and reintroduced in the fatigue life analysis, fatigue life is predictable within the usual 2x scatter factor for damage tolerance analysis.
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 1996 with total page 1364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Fatigue Crack Closure Measurement and Analysis written by R. Craig McClung and published by ASTM International. This book was released on 1999 with total page 487 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1999 with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt:
