Download or read book Prediction of Crack Growth Under Variable Amplitude and Spectrum Loading in a Titanium Alloy written by EP. Phillips and published by . This book was released on 2004 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present paper is concerned with the application of a plasticity-induced crack-closure model, FASTRAN, to predict fatigue-crack growth under various load histories in a thin-sheet Ti-62222 STA titanium alloy. This alloy was a leading candidate for a metallic High-Speed-Civil-Transport (HSCT) aircraft in the United States. The crack-growth model was based on the Dugdale strip-yield model but modified to leave plastically deformed material in the wake of the advancing crack. The model includes the influence of "constraint" on the development of plasticity and closure during constant- and variable-amplitude load histories. The model was used to correlate crack-growth-rate data under constant-amplitude loading over a wide range in crack-growth rates and stress ratios at two service temperatures (room temperature and 175°C). Tests on repeated spike overloads were used to help establish the constraint variations in the model. The model was then used to predict crack growth under two simulated aircraft spectrum load histories at the two temperatures. The spectra were a commercial HSCT wing spectrum and the Mini-TWIST (transport wing spectrum). This paper will demonstrate how constraint plays a leading role in the retardation and acceleration effects that occur under variable- amplitude and spectrum loading. The model was able to calculate the effects of repeated spike overloads on crack growth at the two temperatures, generally within about ± 30 %. Also, the predicted crack-growth behavior under the HSCT spectrum agreed well with test data (within 30 %). However, the model under-predicted the fatigue-crack-growth behavior under the Mini-TWIST spectrum by about a factor-of-two. Some of the differences may be due to fretting-product-debris-induced closure or three-dimensional effects, such as free-surface closure, not included in the model. Further study is needed on life predictions under the Mini-TWIST flight spectrum.

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 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 Prediction of Fatigue Crack Growth Under Spectrum Loads written by AE. Gemma and published by . This book was released on 1979 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reduced crack growth rate caused by each high-low load sequence of a complex load spectrum is modeled by a modified empirical constant-amplitude crack propagation relationship. The modification consists of the replacement of the crack rate term by a fractional derivative. The order of the derivative is a nondimensional parameter which is defined in terms of each high-low load sequence occurring in the spectrum. A cycle-by-cycle solution of the fractional differential equation yields the crack growth behavior for the spectrum. The approach is evaluated by comparing predictions with available experimental results for three aluminum alloys (7075-T6, 7050-T73, 2024-T3), two titanium alloys (Ti-6A1-4V, Ti-6Al-2Sn-4Zr-6Mo) and a nickel base superalloy IN-100. In all cases the method accurately predicted the general trends and estimates were well within a factor of two for 39 out of 40 tests analyzed.

Download or read book Load Interaction Effects on Fatigue Crack Growth in Ti 6Al 4V Alloy written by Robert Peh-ying Wei and published by . This book was released on 1973 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of delay, retardation in the rate of fatigue crack growth, produced by load interactions in variable amplitude loading, on the accurate prediction of fatigue lives of engineering structures is discussed. The effects of a broad range of loading variables on delay in fatigue crack growth at room temperature are examined for a mill annealed Ti-6Al-4V alloy. The results are used to estimate crack growth behavior under programmed loads.

Download or read book Fatigue Crack Growth in Two Advanced Titanium Alloys Under Variable Amplitude Loading at Room and Elevated Temperature written by Andrew Leigh Veit and published by . This book was released on 1996 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Periodic Overload and Transport Spectrum Fatigue Crack Growth Tests of Ti62222STA and Al2024T3 Sheet written by Edward P. Phillips and published by . This book was released on 1999 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Growth and Crack Closure Behavior of Ti 6Al 4V Alloy Under Variable Amplitude Loadings written by M. Jono and published by . This book was released on 1999 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue crack growth tests under constant-amplitude and repeated two-step loadings were carried out on a (? + ?) Ti-6Al-4V alloy which has duplex structure made up of equiaxed primary ?-phase grains with a discontinuous fine ?-phase dispersed in the boundaries. It was found that fatigue crack grew along ?-phase grain boundaries and that the fracture surface was very rough in the low stress intensity region under constant-amplitude loading. On the other hand, in the high region, transgranular crack growth was observed and the fracture surface was relatively smooth. The crack opening point, Kop, was affected by the amplitude of low-level load, ?KL, under repeated two-step loadings where the high-level load amplitude was kept constant. Kop was found to be higher than that predicted by Kop -- Kmax relationship under constant-amplitude loading and the fracture surface was rougher in comparison with that under constant-amplitude loading which has the identical stress intensity range. It was concluded that the crack opening point was controlled by both plasticity-induced crack closure in terms ofKmax and roughness-induced crack closure resulted from rougher surface in ?KL.

Download or read book Fatigue Crack Growth Under Spectrum Loads written by Ralph Ivan Stephens and published by ASTM International. This book was released on 1976 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Propagation and Load Interaction Effects in a Titanium Alloy written by JM. Larsen and published by . This book was released on 2000 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of load interaction effects in Ti-6Al-2Sn-4Zn-2Mo is presented. Simple variable amplitude loading spectra were applied to test samples, and the crack propagation stress intensity factor, KPR, was subsequently measured. The data were condensed to two equations ("master curves") that describe the influence of an unloading cycle after constant amplitude loading and a single overload cycle, respectively. The results suggest that load interaction effects are caused by residual compressive stresses ahead of the crack front, whereas the influence of crack closure is minor.

Download or read book Prediction Methods for Crack Growth Under Variable amplitude Loading written by Harry Zvi Granot and published by . This book was released on 1980 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Periodic Overload and Transport Spectrum Fatigue Crack Growth Tests of Ti2222STA and A12024T3 Sheet written by E. P. Phillips and published by . This book was released on 1999 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Variable amplitude loading crack growth tests have been conducted to provide data that can be used to evaluate crack growth prediction codes. Tests with periodic overloads or overloads followed by underloads were conducted on titanium alloy Ti-6Al-2Sn-2Zr-2Mo-2Cr solution treated and aged (Ti62222STA) material at room temperature and at 350 deg. F. Spectrum fatigue crack growth tests were conducted on two materials (Ti62222STA and aluminum alloy 2024-T3) using two transport lower-wing test spectra at two temperatures (room temperature and 350 deg. F (Ti only)). Test lives (growth from an initial crack half-length of 0.15 in. to failure) were recorded in all of the tests and the crack length against cycles (or flights) data were recorded in many of the tests. The following observations were made regarding the test results: (1) in tests of Ti62222STA material, the tests at 350 deg. F had longer lives than those at room temperature, (2) in tests to the MiniTwist spectrum, the Al2024T3 material showed much greater crack growth retardations due to the highest stresses in the spectrum than did the Ti62222STA material, and (3) comparisons of material crack growth performances on an "equal weight" basis were spectrum dependent.

Download or read book Fatigue Crack Growth of Titanium 62222 Under Variable Amplitude Loading and Three Temperature Conditions written by Christopher J. Cousins and published by . This book was released on 1998 with total page 232 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 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 Recent Developments in Analysis of Crack Propagation and Fracture of Practical Materials written by Herbert F. Hardrath and published by . This book was released on 1978 with total page 24 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 1972 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: