Download or read book An Evaluation of Cold Expansion Methods Used for Improving the Fatigue Life of Fastener Holes in Aerospace Aluminum Alloy 7075 T6 written by Tajbakhsh Navid Chakherlou and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Evaluation of Cold Expansion Methods Used for Improving the Fatigue Life of Fastener Holes in Aerospace Aluminium Alloy 7075 T6 written by Tajbakhsh Navid Chakherlou and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cold Expansion and Interference for Extending the Fatigue Life of Multi layer Metal Joints written by J. M. Finney and published by . This book was released on 1993 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influences of both hole cold expansion and interference-fit fasteners for extending the fatigue life of multi-layer aluminium alloy joint specimens under variable-amplitude loading have been examined experimentally. Improvements in fatigue life were markedly dependent on the degree of load transfer in the specimen joint. The cold expansion of fastener holes enhanced fatigue life in low-load-transfer joints but not in 100%-load-transfer joints. The use of interference-fit fasteners, especially at high degrees of interference, was an effective means of life improvement irrespective of proportion of load transfer. Interfacial fretting limited the improvement in fatigue life of low-load-transfer joints to a factor of about 6, and, although some fretting occurred in 100%-load-transfer joints it was not determinative, and a 40-fold increase in fatigue life was obtained with a combination of hole cold expansion and interference-fit fastener. Joints, Expansion, Aluminum alloys, Cold working, Fatigue life, Interference fit devices, Holes(Opening), Fasteners.

Download or read book Determination of Stress Intensity Factor for Cold Worked Fastener Holes in 7075 Aluminum Using the Crack Growth Method written by William H. Cathey and published by . This book was released on 1975 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress intensity factor calibrations were obtained for thru-the-thickness flaws emanating from cold-worked fastener holes in 7075-T6 aluminum alloy plate using the fatigue crack growth method. Cracks were periodically photographed to determine crack growth rate using a 35 mm camera actuated by a digital counter. Tests were conducted in laboratory air with constant amplitude loading, 30 Hz frequency, and R-factor = 0.05. The J.O. King sleeved cold-working process was used with a nominal diametral interference of 0.012 in. Open-hole specimens were tested at 16 KSI, 25 KSI, and 40 KSI remote stress. K calibrations for open cold-worked holes were in agreement with Grandt's linear superposition solution. Pin-loaded cold-worked holes, tested using a 2000 lb load transferred thru a 0.25 in. pin, showed a twenty-fold increase in fatigue life.

Download or read book Improving the Fatigue Performance of Thick Aluminium Alloy Bolted Joints by Hole Cold expansion and the Use of Interference fit Steel Bushes written by John Yeates Mann and published by . This book was released on 1983 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue tests under a flight-by-flight loading sequence have been carried out on small bolted joint specimens of 23 mm thickness representing part of the spar rear flange/skin attachment in Mirage III aircraft. The investigation has shown that by cold-expanding the bolt holes to take standard oversize bolts, or by installing interference-fit bushes, the fatigue life can be more than doubled compared with the use of standard close-fit bolts in reamed holes. No significant differences were found between the fatigue lives of specimens embodying low-alloy steel or stainless steel bushes. When small-sized residual fatigue cracks are present, hole cold-expansion may be a suitable process for extending the fatigue life. The use of interference-fit bushes is not likely to be an effective method for extending the fatigue lives when large- size residual cracks are present. However, if such cracks can be machined out, the incorporation of large-size interference-fit bushes has the greater potential for providing not only significant extensions in life but also significantly longer lives than the original design detail.

Download or read book Effect of Cold working by Hole Expansion on Fatigue Life of 7075 T7351 and 7475 T761 Aluminum Lugs with and Without Initial Flaws Under Maneuver Loading Spectrum written by Alfred Buch and published by . This book was released on 1985 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue and Corrosion Fatigue Behavior of Cold Worked Fastener Holes in 7075 T651 Aluminum Alloy written by Eric L. Westfall and published by . This book was released on 2001 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Use of Interference Fit Bolts Or Bushes and Hole Cold Expansion for Increasing the Fatigue Life of Thick Section Aluminium Alloy Bolted Joints written by and published by . This book was released on 1983 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detection of fatigue cracks at bolt holes in the main spar of the Mirage III wing during full-scale fatigue tests led to a requirement for refurbishment procedures to extend the fatigue lives at a number of critical locations. One of these, which is covered by this investigation, was the spar lower front flange. Flight-by-flight fatigue tests have been carried out to determine the relative fatigue performance of aluminum alloy bolted joint specimens of 28 mm thickness incorporating close-fit bolts, interference-fit bolts (0.4%), hold cold-expansion (3%), interference-fit steel bushes (0.3%) and a combination of cold-expansion and interference-fit bushes. Fractographic measurements of crack development from the bores of holes in specimens incorporating close-fit bolts in non cold-expanded (reamed) and cold-expanded holes clearly indicated much slower fatigue crack propagation rates from the cold-expanded holes until the crack length was close to the nominal region of transition from the residual compressive to tensile stress zone around the cold- expanded holes. Fatigue tests on cold-expanded hole specimens at different spectrum scaling factors indicated that, under the loading sequence used, each 10% increase in stress reduced the life to about half that at the lower stress level.

Download or read book Riveted Lap Joints in Aircraft Fuselage written by Andrzej Skorupa and published by Springer Science & Business Media. This book was released on 2012-06-23 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue of the pressurized fuselages of transport aircraft is a significant problem all builders and users of aircraft have to cope with for reasons associated with assuring a sufficient lifetime and safety, and formulating adequate inspection procedures. These aspects are all addressed in various formal protocols for creating and maintaining airworthiness, including damage tolerance considerations. In most transport aircraft, fatigue occurs in lap joints, sometimes leading to circumstances that threaten safety in critical ways. The problem of fatigue of lap joints has been considerably enlarged by the goal of extending aircraft lifetimes. Fatigue of riveted lap joints between aluminium alloy sheets, typical of the pressurized aircraft fuselage, is the major topic of the present book. The richly illustrated and well-structured chapters treat subjects such as: structural design solutions and loading conditions for fuselage skin joints; relevance of laboratory test results for simple lap joint specimens to riveted joints in a real structure; effect of various production and design related variables on the riveted joint fatigue behaviour; analytical and experimental results on load transmission in mechanically fastened lap joints; theoretical and experimental analysis of secondary bending and its implications for riveted joint fatigue performance; nucleation and shape development of fatigue cracks in riveted longitudinal lap joints; overview of experimental investigations into the multi-site damage for full scale fuselage panels and riveted lap joint specimens; fatigue crack growth and fatigue life prediction methodology for riveted lap joints; residual strength predictions for riveted lap joints in a fuselage structure. The major issues of each chapter are recapitulated in the last section.

Download or read book Cold Expansion Effects on Cracked Fastener Holes Under Constant Amplitude and Spectrum Loading in the 2024 T351 Aluminum Alloy written by Jacob John Warner and published by . This book was released on 2012 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effectiveness of Fatigue Life Enhancing Fasteners in the Design and Rework of Aircraft Structures written by P. A. Kozel and published by . This book was released on 1985 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue life data were obtained for four different types of fatigue life enhancing (FLE) fasteners installed in new uncracked holes and in reworked, pre-cracked holes. The first condition represented a new design where the FLE fasteners are installed during production. The second condition represented a structural rework in which fastener holes are reamed to a larger size to remove fatigue or fretting damage but might still contain a small undetected crack. Results showed that the FLE fasteners produced approximately the same overall fatigue life in the new design and the rework condition and provided a significant increase in life compared to conventional non-FLE fasteners. Tests were performed with 7075-T6 aluminum alloy under spectrum loading typical of a Navy fighter/attack type of aircraft. For the rework condition, the pre-crack size was limited to .03 inch (.76mm). Flush head fasteners were used in all tests. Keywords: Crack-growth; Fasteners; Structural rework; Joints.

Download or read book Fastener Hole Reinforcement in Composites Using Cold Expanded Inserts written by AC. Rufin and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cold expansion, a technique widely used to increase the fatigue life of holes in metal structures, has been adapted to composite materials as a means to install metal inserts in fastener holes. Thin-walled cold expanded inserts (grommets) are used to reinforce fastener holes that may be sensitive to damage, for example, from repeated fastener installation and removal, or from lightning strike. Thicker inserts with a nut-anchoring feature are a cost-effective alternative to riveted nut plates currently used in composite-fastened assemblies. A comprehensive test program involving mechanically fastened joints in composites with adhesive bonded and cold expanded grommets showed that, in general, cold expanded grommets perform comparably to, or better than, bonded grommets. In the areas of installation costs and resistance to lightning strike damage, cold expanded grommets significantly out-performed bonded grommets. Work on cold expanded rivetless nut plates in carbon/epoxy has proven the viability of the concept.

Download or read book The Effects of Corrosion Cold Expansion and Interference Fit on the Fatigue of Aluminium Alloy Specimens Containing Fastener Holes written by Alexey Nesterov and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue of Aircraft Structures written by United States. Naval Air Systems Command and published by . This book was released on 1966 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Method for Estimating the Fatigue Life of 7075 t6 Aluminum Alloy Aircraft Structures written by Clarence R. SMITH and published by . This book was released on 1965 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this investigation was to assess the validity of the 'Smith Cumulative Damage' hypothesis for 7075-T6 aluminum alloy specimens and structures. It was found that the results of a single-amplitude test (at short life) can be used to estimate the stress at the point of failure, including residual stress. This permits using S-N data for axially loaded unnotched specimens to predict spectrum life. Excellent agreement was found between calculated and experimental lives of full-scale structures; however, test lives of small specimens were consistantly shorter than predicted. (Author).

Download or read book Extended Study of Flaw Growth at Fastener Holes written by T. M. Hsu and published by . This book was released on 1978 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical and experimental investigation was conducted to characterize the fracture and cyclic-growth behavior of cracks emanating from various types of fastener holes, such as open, close-tolerance, interference- fit, and cold-worked fastener holes. An analytical approach was developed for estimating stress intensity factors for through cracks emanating from these types of fastener holes. Approximate stress intensity factors for quarter- elliptical cracks emanating from a corner of the same types of fastener holes were derived from corresponding through-crack solutions. Two alloy plates (2219- T851 aluminum and 6Al-4V (ELI) beta annealed titanium) with and without intentional initial flaws were tested under constant amplitude cyclic load and flight-by-flight fighter and bomber spectrum loads. Two initial flaw shapes corresponding to a quarter-circular corner crack and a through-the-thickness crack and three initial crack lengths (small, intermediate and large) were used in the test program. Three levels of cold working and interference and one level of fastener load transfer were included for each alloy. The amount of load transferred through the loaded fastener was maintained uniformly at the level which produced a bearing stress equal to the far-field stress. Correlations between calculated stress intensities and those reduced from fatigue crack growth data were good, except for very small cracks growing from the cold-worked holes. Also, the natural cracks initiated in the fatigue tests were most commonly corner and embedded types whose shapes corresponded quite closely to the quarter- and semi-elliptical shapes used in the analyses.

Download or read book An Analysis of Residual Stresses and Displacements Due to Radial Expansion of Fastener Holes written by A. F. Grandt and published by . This book was released on 1979 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-expanding fastener holes with an oversize mandrel has received considerable attention for use in aircraft structures, since this process has been shown tto greatly improve the fatigue life of fastener holes. The deformation theory of plasticity is used here to determine the residual stress and displacement field caused by this process. Employing plane stress assumptions, general results are obtained for various interference levels and are presented in a graphical form useful to the designer. In addition, this analysis indicates that there is an optimum level of interference dependent primarily on the plate geometry. The optimum interference levels agree well with experience values established by fatigue testing in aircraft structural alloys. (Author).