Download or read book An Indirect Technique for Determining Closure Free Fatigue Crack Growth Behavior written by SW. Smith and published by . This book was released on 2000 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of stress ratio (R) and maximum applied stress-intensity factor (Kmax) on fatigue crack growth rate (da/dN) have been investigated. Fatigue crack growth behavior was analyzed by plotting applied cyclic stress-intensity factor (?K) versus applied Kmax for an ?+? titanium alloy (Ti 6-2-2-2-2) at several values of da/dN. This analysis revealed two distinct regions of fatigue crack growth behavior. At threshold da/dN (? 10-10 m/cycle) and for Kmax 4.6 MPa?m the threshold cyclic stress-intensity factor (?Kth) is greatly influenced by crack closure. For closure free fatigue crack growth (Kmax 4.6 MPa?m), a subtle but distinct decrease in ?Kth is observed with increasing Kmax. Plots of ?K versus Kmax were also generated for AA 2024 test data produced in two different studies. These data also revealed two distinct regions of fatigue crack growth behavior consistent with the Ti 6-2-2-2-2 results. This methodology can be used to determine closure free fatigue crack growth and to monitor subtle changes in ?Kth.
Download or read book Fatigue Crack Growth Thresholds Endurance Limits and Design written by J. C. Newman and published by ASTM International. This book was released on 2000 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Contains 24 papers from the November, 1998 symposium of the same name, sponsored by the ASTM Committee E8 on Fatigue and Fracture, and presented by Newman and Piascik (both of the NASA Langley Research Center). The papers focus on such areas as fatigue-crack growth threshold mechanisms, loading and specimen-type effects, analyses of fatigue-crack-growth-threshold behavior, and applications of threshold concepts and endurance limits to aerospace and structural materials. Annotation copyrighted by Book News, Inc., Portland, OR.
Download or read book Analytical and Experimental Study of Near Threshold Interactions Between Crack Closure Mechanisms written by John A. Newman and published by . This book was released on 2003 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of O2 H2O and N2 on the Fatigue Crack Growth Behavior of an Alpha Beta Titanium Alloy at 24 C and 177 C written by Stephen W. Smith and published by . This book was released on 2001 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Testing and Analysis Under Variable Amplitude Loading Conditions written by Peter C. McKeighan and published by ASTM International. This book was released on 2005 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue and Fracture Mechanics written by Walter G. Reuter and published by ASTM International. This book was released on 2002-12-31 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the whole of Asia and the Pacific region, this text provides both an analytic overview and specific data for each of the 60 countries. Introductory chapters cover regional issues, including: a regional review with the year's trends, developments and key events' analysis of the threat of terrorism in the region; the effects of deflation on the economy; the water crisis and its impact on the poor; and the successes and failures of micro-credit in the region.
Download or read book Fatigue and Fracture Mechanices written by Steven R. Daniewicz and published by ASTM International. This book was released on 2005-09 with total page 591 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Characteristics of Thin Sheet Titanium Alloy Ti 6 2 2 2 2 written by and published by . This book was released on 2001 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue and Fracture Mechanics written by and published by . This book was released on 2001 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Structural Integrity Cyclic loading and fatigue written by I. Milne and published by Elsevier. This book was released on 2003 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue and Fracture Mechanics written by Kenneth L. Jerina and published by ASTM International. This book was released on 2000 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of the Adjusted Compliance Ratio Technique for Measuring Crack Closure in Ti 6A1 4V written by SM. Graham and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Standard fatigue crack growth rate tests within the upper threshold and Paris Law regions were conducted on specimens from three large, standard-grade Ti-6Al-4V forgings in order to evaluate the adjusted compliance ratio (ACR) method for closure correction. Constant R-ratio tests were conducted to generate data containing crack-tip closure, and constant Kmax tests were performed to produce high R ratio, and hence closure-free, data in the threshold and upper threshold regimes. Direct comparisons are made of the closure corrected data generated using the current ASTM slope offset method and the ACR method. While it is clear that the ACR technique is easier to implement and will always lead to less closure correction than the slope offset technique, it is not clear which is more accurate. It appears that the slope offset method may be overcorrecting for closure effects and the ACR method may be undercorrecting.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Near Tip and Remote Characterization of Plasticity Induced Fatigue Crack Closure written by DL. Davidson and published by . This book was released on 1999 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: An elastic-plastic finite element model and high resolution experimental measurements of growing fatigue cracks are employed in partnership to investigate the relationship between crack closure, near-tip deformation behavior, and remote load-displacement measurements. The model focuses on plasticity-induced closure effects for fatigue cracks in the Paris regime, while the experiments study fatigue cracks in the Paris and near-threshold regimes in a variety of materials. The suitability of the ASTM compliance offset method and the recently-proposed adjusted compliance ratio (ACR) method to characterize near-tip closure effects is evaluated. The experiments and analyses both show that crack-tip strains below the crack-opening stress, Sop, are a relatively small fraction of the total crack-tip strain range for cracks in the Paris regime, and therefore may be insignificant for crack-tip deformation and damage and crack growth. The experiments further indicate that crack-tip strains below Sop are a relatively larger fraction of the total crack-tip strain at lower ?K values, nearer the threshold, where Sop values are higher. The current ASTM compliance offset procedure for determining the crack opening load is shown to provide accurate information about true crack-tip opening loads in theory. However, due to the limited sensitivity of the method in practice, and the corresponding need to employ a non-zero compliance offset, the method gives underestimates of opening and closing loads that may be considerably in error relative to the true crack-tip values. The current ACR technique does not appear to do a good job of characterizing the near-tip deformation response for cracks in the Paris regime, because remote displacement measurements do not appear to be adequately sensitive to near-tip strains.
Download or read book Plasticity and Roughness Closure Interactions Near the Fatigue Crack Growth Threshold written by RS. Piascik and published by . This book was released on 2003 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced model has been developed to calculate interactions between plasticity and roughness closure mechanisms resulting in the fatigue crack growth threshold. Near-threshold closure is complex because multiple closure mechanisms are likely, including roughness-, oxide-, and plasticity-induced crack closure. Results show closure first occurs either at the crack tip (tip contact), or at the fatigue-crack-surface asperity nearest the crack tip (asperity contact), in the absence of load history effects. Model calculations, verified by laboratory experiments, reveal a transition from tip contact to asperity contact produces fatigue crack growth threshold behavior; here, both model and experiment show that an abrupt increase in closure (asperity contact) results in the rapid decrease in fatigue crack growth rate at threshold. A comparison of an advanced crack-tip load displacement measurement technique, and standard global compliance methods show that global methods lack the sensitivity to accurately characterize crack closure at threshold.
Download or read book Corrosion Tests and Standards written by Robert Baboian and published by ASTM International. This book was released on 2005 with total page 887 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analyses of Fatigue Crack Growth and Closure Near Threshold Conditions for Large Crack Behaviour written by J. C. Newman and published by . This book was released on 1999 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
