Download or read book Crack closure and relaxation effects on fatigue crack growth in A1 2219 alloy written by Edward Granville Sewell and published by . This book was released on 1977 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Crack Closure and Fatigue Crack Growth in 2219 T851 Aluminum Alloy written by and published by . This book was released on 1976 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of specimen thickness, stress ratio (R) and maximum stress intensity factor (K sub max) on crack closure (or opening) and on fatigue crack growth kinetics were studied using a 2219-T851 aluminum alloy. The crack length and the occurrence of crack closure were measured by an electrical potential method. The experimental work was carried out within the framework of linear-elastic fracture mechanics.

Download or read book The Influence of Hold Times on Fatigue Crack Growth of Aluminum Alloys written by H. L. Marcus and published by . This book was released on 1980 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of the research on fatigue crack growth in aluminum alloys are described in three general areas. The first relates the influence of hold time at an underload that follows an overload on the fatigue crack growth retardation behavior of the 7075 and 2219 aluminum alloys. A very distinct effect on retardation with hold time is observed. The effect is microstructure dependent with the time dependence behavior extending over a longer period for the high strength materials. This well-defined time dependence clearly shows that lifetime predictions based on accelerated short hold time tests could be very non-conservative. The influence of humidity was also determined using vacuum as a reference environment. The second aspect of the research investigated the nature of the residual displacement, d, that leads to the crack closure phenomena. The last major emphasis was to investigate how gaseous environments interact with fatigue crack growth in aluminum alloys. Combined AES/SIMS studies were made of fracture surfaces taken from fatigue crack growth specimens fatigued in vacuum and subsequently exposed to and fatigued in a range of environments.

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 Effects of R Factor and Crack Closure on Fatigue Crack Growth for Aluminum and Titanium Alloys written by M. Kaplan and published by . This book was released on 1974 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following the crack closure studies of Elber, experiments were performed which appear to corroborate the link between the load required to open a crack at its tip and the shift in crack growth rate curves with stress ratio. Measurements of fatigue crack growth rates and closure loads were made on compact tension specimens for positive stress ratios of R=0.08 to R=0.8 and at rates between 10-7 and 10-5 in./cycle. An Rcut exists for 2219-T851 and recrystallization annealed Ti-6A1-4V wherein da/dN versus ?K data does not shift to faster rates with increasing stress ratios above R=0.32 and R=0.35, respectively. The physical basis for the Rcut can be adequately explained in terms of crack tip closure. Fatigue S-N data also exhibited an Rcut when replotted as ?S-N.

Download or read book Fatigue Crack Growth Studies in 2219 T851 written by Allison Sermonte Warren and published by . This book was released on 1983 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress Ratio Effects on Crack Opening Loads and Crack Growth Rates in Aluminum Alloy 2024 written by William T. Riddell and published by . This book was released on 1998 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Compressive Loading on Fatigue Crack Growth Rate and Striation Spacing in Type 2219 T851 Aluminum Alloy written by L. Albertin and published by . This book was released on 1981 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Macroscopic crack growth rates, da/dN, have been obtained as a function of the stress-intensity factor range, ?K, for Type 2219-T851 aluminum in ambient air at load ratios, R, of 0.1 and -1. Microscopic modes of crack extension were also determined by transmission electron fractography. Fatigue striation spacings, S, compared well with da/dN when static fracture modes--primarily dimpled rupture--did not occur. These static fracture modes were more prevalent during tension-tension loading at R = 0.1 than during tension-compression loading at R = -1, and they contributed to higher growth rates at the positive load ratio. The relationship between striation spacing and ?K/E (where E is the elastic modulus) in Type 2219-T851 aluminum was found to be similar to those for other engineering alloys. This relationship was observed to be much less sensitive to changes in the load ratio than the relationship between da/dN and ?K.

Download or read book Role of Crack tip Stress Relaxation in Fatigue Crack Growth written by Ashok Saxena and published by . This book was released on 1979 with total page 18 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 Constant Amplitude and Post overload Fatigue Crack Growth Behavior in PM Aluminum Alloy AA 8009 written by and published by . This book was released on 1991 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Load Interaction on Fatigue Crack Growth and Crack Closure in Aluminium Alloys written by Fraser J. McMaster and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The effect of thickness of fatigue crack propagation in 7475 T731 aluminum alloy sheet written by Ralph Anthony Daiuto and published by . This book was released on 1984 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Humidity on the Fatigue Crack Growth Rate in Aluminum Alloy 8090 T8771 Thick Plate written by and published by . This book was released on 1995 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this investigation was to determine the effect of relative humidity on the fatigue crack growth rate in aluminum alloy 8090 thick plate thermomechanically processed to the T8771 condition. High and low humidity fatigue crack growth rate data were generated for three load-ratios, 0.1, 0.33, and 0.7, from the near threshold through intermediate linear region. The test material showed a significant crack closure for load-ratios equaling 0.1 and 0.33. Above the near threshold region the saturated air environment caused an increased fatigue crack growth rate. For a laboratory air environment and an R-ratio equal to 0.1, the crack growth rate leveled off to a plateau, with the growth rate increasing gradually. The slowed growth rate was related to considerable fracture surface roughness; this effect diminished when the R-ratio was 0.33 and disappeared in the absence of crack closure when the R-ratio equals 0.7. When the load-ratio equaled 0.1 in the near threshold region, material tested in high humidity produced a larger threshold stress intensity range for fatigue crack propagation compared to laboratory air. The phenomena was attributable to additional environmental-generated debris bridging the fracture surfaces, which caused increased closure; the effect diminished with increased R-ratio where greater crack opening displacement reduced closure effects. (MM).

Download or read book Load Interaction Effects on Fatigue Crack Growth in Ti 6Al 4V Alloy written by and published by . This book was released on 1973 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Influence of Crack Closure on Fatigue Crack Growth Thresholds in 2024 T3 Aluminum Alloy written by EP. Phillips and published by . This book was released on 1988 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crack opening loads were determined in load-shedding fatigue crack growth threshold tests on 2024-T3 aluminum alloy at stress ratios R of -2, -1, 0, 0.33, 0.5, and 0.7. The effects of load-shedding procedure and rate were investigated. Values of threshold ?K were found to vary significantly with R, whereas values of threshold effective ?K did not. That is, the variation of threshold ?K with R was almost completely explained by accounting for the measured variation in crack opening load behavior with R. The load-shedding guidelines of ASTM Test Method for Measurement of Fatigue Crack Growth (E 647) produced a threshold ?K value for R = 0.7 that was in agreement with the value determined using a procedure that should minimize closure effects (constant-Kmax, increasing-Kmin test). At both R = 0 and R = 0.7, high load-shedding rates produced high values of threshold ?K caused by large closure effects.

Download or read book Effects of Underloads on Fatigue Crack Growth Data Tabulations written by and published by . This book was released on 1977 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of single overload-underload interaction on constant amplitude crack growth in 2219-T851 aluminum alloy are characterized in terms of delay cycles, affected zone sizes and overload shut-off ratios. Data are presented showing the effects of overload-underload/underload-overload sequences, overload magnitude, underload magnitude, and the constant amplitude maximum and minimum. The effects of hold periods in both tension and compression are also experimentally investigated. Delay cycle data are correlated with predictions from three different crack growth retardation models; namely the generalized Wheeler model, the generalized Willenborg model and the Grumman closure model. For each model, predictions are made using an assumed plastic zone radius and diameter for both plane stress and plane strain conditions and model comparisons are made. Correlations of measured affected zone sizes with the four different assumed plastic zone sizes are also presented. Sensitivities of the generalized Wheeler and generalized Willenborg models to overload shut- off ratio and threshold stress intensity factor are determined. Prediction sensitivity to three different crack growth equations for the 2219-T851 aluminum alloy is also evaluated. Recommendations for future work in development of crack growth retardation models are presented.