Download or read book Effect of Warm Prestressing on Fatigue Crack Growth Curves at Low Temperatures written by A. Bussiba and published by . This book was released on 1985 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-temperature fatigue crack extension is studied in precracked single-edge-notched specimens of AISI 4340 steel. Steady-state crack extension in tension-tension fatigue and cyclic loading in conjunction with warm prestressing (WPS) are particularly emphasized. Effects of WPS on the fatigue crack growth curve are demonstrated and discussed. Special attention is given to the cleavage fracture mode, which dominates the features of the fatigue crack growth curve below the ductile-brittle transition (DBT) temperature. In AISI 4340 steel, which is characterized by DBT, WPS affects the alternative fracture mode and therefore alters the lower and upper bound values Kth and KIfc, respectively. For a more complete view, the behavior of AISI 304 stainless steel is discussed. The experimental results at low temperatures are mainly interpreted in terms of a transition in the cumulative crack tip damage process, induced by characteristic values of the stress intensity range amplitudes (?K).
Download or read book Fatigue at Low Temperatures written by Ralph Ivan Stephens and published by ASTM International. This book was released on 1985 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Behavior of a High Strength Steel written by Maurice F. Amateau and published by . This book was released on 1971 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue crack growth behavior of high-strength Ladish D6AC steel was examined under various conditions of frequency, environment, temperature, stress ratio, and stress intensity history. Materials with fracture toughness ranging from 50 to 100 ksi/sq. in., but with the same yield strength of 220 ksi, were examined. Variations in fracture thoughness do not have a strong effect on crack growth rate at stress intensity levels within the log-linear portion of the crack growth curves. Different environments, such as dry air, laboratory air, and distilled water, were found to produce different fatigue crack growth behavior at 1 Hz but not at 10 Hz loading frequency. The lowest crack growth rate occurred in dry air, while the aggressive environment of distilled water affected the crack growth rate more severly at lower stress intensity levels. The effects of temperature over the range from -40 to 175F are a uniform shift of the growth curve to low crack growth rates and a lowering of the stress intensity level for the onset of rapid fatigue crack propagation. Suppression of crack growth rate following high prior stress cycles is the most significant effect of stress history. This effect cannot be explained in terms of the relative plastic zone sizes alone. (Author).
Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Investigation of Constraint Effect on Fatigue Crack Growth Rate Measurements written by Veronika Hochfellner and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For the purpose of reliable life prediction the fatigue crack growth behaviour of a material has to be well-known. Therefore standardized fatigue crack growth tests are made with test specimens of the material. The obtained fatigue crack growth data is taken as material specific data and is given without any information of the test conditions and used specimen geometry. However, in several studies a geometry dependency of the test specimen on the fatigue crack growth data is found. Hence in this investigation experiments on fatigue crack growth behaviour are made with two different specimen geometries, the middle tension specimen M(T) and the compact (tension) specimen C(T). The direct current potential drop (DCPD) method is used to determine the crack lengths which is calibrated with the aid of beach marks and crack detection gauges. Two different configurations of the DCPD method are implemented to gain acceptable results. With the obtained data fatigue crack growth curves are established which are analysed regarding the geometry influence of the used test specimens. Discrepancies in the fatigue crack growth curves between the tested specimens are found. With these findings an approach is tested to create a material curve which is independent of the specimen geometry. However, this approach is not leading to satisfactory results. The implementation of the DCPD method in its main configuration on the used experimental setup proves to be applicable for fatigue crack growth tests on different geometries and will be used in further studies at low temperatures.
Download or read book Fracture Mechanics written by John H. Underwood and published by ASTM International. This book was released on 1986 with total page 837 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Growth Rates of A 508 2 Steel in Pressurized High Temperature Water written by W. H. Cullen and published by . This book was released on 1983 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1994 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Consequences of the Thermal Effects Generated During Fatigue Crack Growth on the Mode One Stress Intensity Factor written by Zaid Boussattine and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: By subjecting a cracked specimen to a cyclic loading, thermal effects take place and create a heterogeneous temperature field around the crack tip. Those thermal effects are associated with coupling and dissipative heat sources, namely: (i) the heat source due to thermoelastic coupling generated by the hydrostatic part of the stress tensor related to cyclic mechanical loading; (ii) the heat source due to intrinsic dissipation associated with the self-heating phenomena originating from plasticity at the microscopic scale; (iii) and the heat source due to cyclic plasticity, at the macroscopic scale, which occurs in the reverse cyclic plastic zone ahead of the crack tip, and dissipates into heat. The overall heterogeneous temperature field resulting from the heat sources induces a heterogeneous stress field due to thermal expansion phenomena. As a consequence, the stress state over the crack is modified and leads to modify the stress intensity factor, which is a key parameter in modeling fatigue crack growth. Therefore, the aim of this PhD thesis is to quantify the consequences of the heat sources on the stress intensity factor, in the case of a long propagating fatigue crack.
Download or read book NRL Report written by and published by . This book was released on 1976 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Cryogenic Engineering Materials written by A. F. Clark and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fifth International Cryogenic Materials Conference (ICMC) was held in Colorado Springs, Colorado in collaboration with the Cryogenic Engineering Conference (CEC) on August 15-19, 1983. The growth and success of the joint conferences is a result of their complementary program and close cooperation. Materials remain a challenge in the application of cryogenic technology and sometimes, as in the case of superconductors, are the driving force for the technology. The association of materials and cryogenic engineers increases their awareness of recent research in their respective fi. elds and influences the course of future research and applications. Many contributed to the success of the 1983 conference: E. W. Collings of Battelle Memorial Institute was the ICMC Confer ence Chairman; M. Suenaga of Brookhaven National Laboratories, the ICMC Program Chairman; and L. L. Sparks of the National Bureau of Standards, the ICMC Local Arrangements Chairman. J. M. Wells and A. I. Braginski of Westinghouse R & D Center, G. Hartwig of the Nuclear Research Center of Karlsruhe, and K. T. Hartwig of the University of Wisconsin assisted the Program Chairman in metallic metals, superconducting materials, nonmetallic materials, and cryo physical properties, respectively. Excellent conference management was provided by Centennial Conferences. We especially thank M. Stieg, who coordinated the preparation of the papers for this volume. The CEC Board, especially their conference chairman, C. D. Henning of Lawrence Livermore National Laboratories, contributed very substan tially to conference planning and implementation.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1970-03 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Low Temperature on Apparent Fatigue Threshold Stress Intensity Factors written by KA. Esaklul and published by . This book was released on 1985 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Near-threshold fatigue crack growth in high-strength low-alloy (HSLA) steel, Fe, and Fe-Si alloys was found to depend on test temperature from room temperature down to 123 K. Near-threshold crack growth rates were lowered and threshold stress intensity factors increased with decreasing temperature. A "prominent" closure was observed for all test temperatures and materials and was further confirmed by the examination of fracture surfaces. The magnitude of closure increased with decreasing temperature, suggesting a dependence on yield strength and fracture morphology. The effects of R ratio were found to be closure-related for the same fracture processes. However, a change in the fracture process, (e.g., to cyclic cleavage) may lead to a ?Kth(eff) dependence on load ratio even at very high R values. Hence mean stress may affect threshold independently of any closure-related phenomena. A reasonable correlation was obtained with a theoretical model for closure that could account for both geometrical and reversed plasticity phenomena.
Download or read book Aerospace Structural Metals Handbook written by and published by . This book was released on 1989 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiscale Phenomena in Plasticity From Experiments to Phenomenology Modelling and Materials Engineering written by Joël Lépinoux and published by Springer Science & Business Media. This book was released on 2000-05-31 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: The various scales of the physical phenomena occurring during plastic flow are reviewed from the atomic level to the constitutive laws, from both theoretical and experimental sides. The fundamentals of plastic flow are revisited, revealing the impact of recent experimental breakthroughs on the theoretical formulation. New developments (constrained plasticity, indentation) are also addressed. The importance of atomic scale phenomena on macroscopic mechanical behaviour are demonstrated in the case of cross-slip and its influence on fatigue properties, and in the effect of hydrogen on ductility. These developments emphasise the importance of the numerical methods used to connect the various scales and show that much remains to be done in this area. Classical fundamental problems, such as the brittle to ductile transition, are described by both experimentalists and theoreticians, as are constrained and heterogeneous deformation.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
