Download or read book Characterization of Residual Stresses in an Eccentric Swage Autofrettaged Thick Walled Steel Cylinder written by and published by . This book was released on 1992 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the swage autofrettage process, partial autofrettage was achieved by driving an oversized mandrel through the cylinders to cause plastic deformation. In this work, we made experimental and theoretical investigations of residual stresses in a swaged asymmetric thick-walled cylinder with small wall variations. Hoop and radial residual stress distributions, as well as angular hoop stress variations at the inside and outside diameter of the cylinder, were determined by using a single-exposure position-sensitive scintillation x-ray diffraction detection system. Our experimental results were in good agreement with the residual stress distributions predicted from Tresca's hydraulic autofrettage model. Deviations of hoop residual stress at the bore may be attributed to Bauschinger's effect. Finite element analysis using ABAQUS code on a Convex supercomputer was used to model the swage autofrettage process. Small angular residual stress variations were predicted due to the eccentricity of the cylinder. The finite element model predictions of residual stress distribution were in general agreement with experimental results except near the bore. Preliminary results of an alternative finite element method showed a reduced compressive hoop stress near the bore, similar to the results obtained by assuming Bauschinger's effect. Residual Stress, Finite Element Analysis, Pressure Vessel, Reverse Yielding, Eccentric Cylinder, X-Ray Diffraction, Swage Autofrettage, Bauschinger's Effect, ABA US Code.

Download or read book Residual Stresses in Swage autofrettaged Thick walled Cylinders written by Graham Clark and published by . This book was released on 1982 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autofrettage of thick-walled pressure vessels involves permanent expansion of the cylinder bores using hydraulic pressure or an oversize swage, and is used to increase the elastic strength of the cylinder. The beneficial residual stresses which produce this effect also retard the growth of fatigue cracks which may form at the bore surface on cyclic pressurization, and are therefore of major importance in determining the life of the cylinders which are fatigue-limited in operation., This report describes predictions of residual stress distributions and cylinder expansions for swage autogrettage of a large-calibre gun barrel forging, and evaluates these predictions by comparison with experimental residual stress determinations. (Author).

Download or read book Residual Stress Analysis in Swage Autofrettaged Thick Walled Cylinders by Position Sensitive X Ray Diffraction Techniques written by and published by . This book was released on 1994 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental and theoretical investigations were made for swage autofrettage partially plastic ASTM A723 steel cylinders with an outside diameter (OD) to inside diameter (ID) ratio of 2.75 and 74 percent overstrain. Residual stress radial distribution and angular stress distribution around the bore were analyzed using two position-sensitive x-ray diffraction stress analyzers. Theoretical calculation was made by implementing an interactive, iterative Lotus Works spreadsheet residual stress model on an IBM PC. The model was based on the classical solution to the elastic-plastic deformation problem of a symmetric thick walled cylinder under internal pressure, including reverse yielding effect. Angular stress distribution data at the ID and OD indicated that non-axisymmetric deformation had occurred during yielding of the cylinders. Excellent agreement was obtained between experimental results and theoretical predictions, including the Bauschinger effect near the bore. By comparing experimental data with theoretical calculations for the 74 percent overstrained cylinders, the Bauschinger factor for the A723 steel was determined to be close to 0.5. Residual stress analysis for the entire cylinder is suggested in the future. Residual stress, Swage autofrettage, Bauschinger's effect, Position- sensitive stress analyzer, X-Ray diffraction, Pressure vessel, Reverse yielding, Plastic deformation.

Download or read book Residual Stress in a Swage Autofrettaged Steel Cylinder with Semi Circular Mid Wall Channels written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray diffraction residual stress distribution analysis was performed for a swage autofrettaged, thick-walled, A723 steel compound cylinder with axial semi-circular mid-wall channels. Because of the existence of high stress gradient components in the stress distribution, the effect of spatial resolution and the x-ray beam spread function were investigated. Experimental stress measurements were compared with results from Tresca's model of a partially autofrettaged solid cylinder. Measured residual stresses were interpreted using an ABAQUS finite element model. Our experimental results verified most features of the predicted hoop stress distribution, including the high stress gradients and compressive stresses near the channel root areas. However, significantly reduced compressive stress levels were observed both near the bore and near the channel roots. An overestimate of fatigue lifetime could result if the reduction of compressive stresses observed experimentally were not taken into account. In solid autofrettaged cylinders, reduction of compressive stresses near the bore has been attributed to the Bauschinger effect. However, there is no analytical model incorporating the Bauschinger effect in the current geometry. This work demonstrated that the introduction of the semi-circular channels in a solid cylinder significantly modified the magnitude and location of stress fields. Both the bore and the channel roots are critical sites for stress concentration. Our analysis further determined that the channel roots were the most critical sites where cracks and failure should occur. Fatigue test results verified that cracking and failure occurred at the channel roots.

Download or read book Prediction of Residual Stresses in an Autofrettaged Thick Walled Cylinder written by P. C. T. Chen and published by . This book was released on 1983 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the earlier results for residual stresses are based on the assumption of elastic unloading. In this report, the prediction of residual stresses for the case of reverse yielding including the combined Baushinger and hardening effect will be reported for an autofrettaged thick-walled cylinder. The Bauschinger effect factor is varying as a function of overstrain. The strain-hardening effect is considered with different parameters used for loading and unloading process. The new results indicate that the influence of the combined Bauschinger and hardening effect on residual stress distribution is significant. (Author).

Download or read book Analysis of the Swage Autofrettage Process written by and published by . This book was released on 1992 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The autofrettage process is a well-known method to improve the working strength and fatigue life of thick-walled cylinders. In the conventional viewpoint, the cylinder is pressurized beyond its elastic limit in order to produce a beneficial residual stress pattern with large compressive hoop stresses at the bore. In practice, this has been accomplished by the swage process in which an oversized tungsten carbide mandrel is pressed through the bore to produce a similar effect. The analysis of this problem has not been possible until the development of high-level finite element codes and high- performance vectorized computers. This combination was utilized to accomplish a detailed analysis of the swage process in a short section of a 105-mm cannon tube.

Download or read book The Bauschinger and Hardening Effects on Residual Stresses in an Autofrettaged Thick Walled Cylinder written by P. C. Chen and published by . This book was released on 1984 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the earlier solutions for residual stresses were based on the assumption of elastic unloading and only a few considered reverse yielding. In this report a new theoretical model for a high strength steel is proposed and a closed-form solution for calculating residual stresses in autofrettaged tubes has been obtained. The new results indicate that the influence of the combined Bauschinger and hardening effects on the residual stress distribution is significant.

Download or read book Influence of Bauschinger Effect on Residual Stress and Fatigue Lifetimes in Autofrettaged Thick Walled Cylinders written by AP. Parker and published by . This book was released on 1999 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work addresses the influence of Bauschinger effect upon residual stresses and associated fatigue lifetimes for pressurized, autofrettaged thick cylinders.The model employed allows for the variation with radius of Bauschinger Effect Factor (BEF) thoughout the autofrettaged tube since the percentage plastic strain, which determines BEF, will vary from a maximum value at the bore to zero at the elastic-plastic interface.

Download or read book Autofrettage Processes written by Uday S Dixit and published by CRC Press. This book was released on 2019-09-23 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autofrettage Processes: Technology and Modeling deals with the technology and modeling of autofrettage processes, explaining the subject in a lucid manner. It highlights how the theory of plasticity and finite element modeling are applied in the modeling of autofrettage processes. Aimed at senior students of mechanical, production, automobile, and chemical engineering, it has the potential to directly benefit practicing engineers and industrials, owing to the inclusion of topics like thermal autofrettage. Key Features: Provides a general introduction to autofrettage Covers the application of theory of plasticity and finite element modeling of autofrettage processes Offers exposure to newer autofrettage processes that to date have not been implemented in industries, along with useful practical data

Download or read book Residual Stresses in Thick walled Cylinders Resulting from Mechancially Induced Overstrain written by T. E. Davidson and published by . This book was released on 1963 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autofrettage is a process for inducing elastic response in thick-walled cylinders subjected tointernal pressures which otherwise cause plastic strains. To extend the use of autofrettage to higher pressure applications and to eliminate many of the problems encountered in the use of the conventional process based on the use of direct internal hydrostatic pressure, a new technique has been developed which utilizes the mechanical advantage of a silding wedge to produce the desired bore enlargement. Since the use of a sliding wedge or mandrel will induce shearing forces at the mandrel-cylinder interface, the resultant residual stress distribution will differ from that theoretically predicted as characteristic of the direct hydrostatic process. It is the purpose of this work to determine the residual stress distribution as a function of magnitude of overstrain and diameter ratio, and how it affects the reyielding characteristics of cylinders autofrettaged by this technique. (Author).

Download or read book Influence of the Bauschinger Effect on Residual Stress and Fatigue Lifetimes in Autofrettaged Thick Walled Cylinders written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work addresses the influence of Bauschinger effect upon residual stresses and associated fatigue lifetimes for pressurized, autofrettaged thick cylinders. The model employed allows for the variation with radius of Bauschinger Effect Factor (REF) throughout the autofrettaged tube since the percentage plastic strain, which determines BEF, will vary from a maximum value at the bore to zero at the elastic plastic interface. Accounting for BEF variability, it is demonstrated that the residual compressive hoop stress at the inner radius of the tube reaches a maximum value at the percentage overstrain level below which reversed yielding does not occur. Existing experimental residual stress measurements from a variety of sources are shown to support this thesis. This value of overstrain may serve to maximize crack initiation lifetime in autofrettaged thick cylinders. For a tube with significant heat checking and associated initial crack like defects, it is necessary to consider fatigue crack growth rates governed by a crack growth law such as Paris's Law. For a tube of radius ratio 2.0 and at a value of approximately 40 percent overstrain, slightly in excess of that for the onset of reversed yielding, the fatigue lifetime exhibits a maximum value. Fatigue lifetimes achieve a maximum value at overstrain levels in which yielding reaches 1.4 times bore radius and are almost constant thereafter. Furthermore, such extended overstrain leads to a small increase in residual stress at the outside diameter (OD), thus increasing R ratio at that location and reducing fatigue lifetime for crack growth originating at the OD. Existing experimental lifetime measurements are shown to require the inclusion of BEF to properly account for these observed lifetimes.

Download or read book Effect of Autofrettage on the Fracture Strength of Thick walled High Pressure Cylinders written by Rasha Rabeh and published by . This book was released on 2018 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Residual Stress in Swage Autofrettaged Cylinders with Axial Semi Circular Mid Wall Cooling Channels written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABAQUS finite element modeling and experimental residual stress mapping have been performed for several swage autofrettaged compound cylinders with semicircular mid-wall cooling channels. The experimental results verified most features of ABAQUS-predicted stress distributions, except near the bore and at the channel roots, where significantly reduced compressive residual stresses were observed. These observations have been attributed to reverse yielding effect in these areas.

Download or read book Pressure Vessel Design Manual written by Dennis R. Moss and published by Butterworth-Heinemann. This book was released on 2012-12-31 with total page 825 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. - Covers almost all problems that a working pressure vessel designer can expect to face, with 50+ step-by-step design procedures including a wealth of equations, explanations and data - Internationally recognized, widely referenced and trusted, with 20+ years of use in over 30 countries making it an accepted industry standard guide - Now revised with up-to-date ASME, ASCE and API regulatory code information, and dual unit coverage for increased ease of international use

Download or read book Transactions of ASME written by and published by . This book was released on 1897 with total page 1288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of Residual Stress in Thick walled Cylinders written by Johah Hsien-Yung Lee and published by . This book was released on 1979 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strengthening and Joining by Plastic Deformation written by Uday Shanker Dixit and published by Springer. This book was released on 2018-06-05 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on strengthening and joining materials by means of plastic deformation, gathering extended research papers presented at the AIMTDR 2016 conference. Plastic deformation is used in materials processing to improve the strength of the material. For example, the rod/screw used to connect the cooker handle to the main body has to be strong and sustainable; such rods can be strengthened by plastic deformation (using multi-stage forming operations etc.). Similarly, joining by means of plastic deformation is highly valuable since it avoids the material and environmental degradation often caused by fusion welding processes. The book discusses various processing techniques in which plastic deformation is used to strengthen materials – e.g. in equal channel angular extrusion, autofrettage etc., or to join materials without melting them – e.g. in friction stir processing, riveting etc. Offering an extensive guide, the book includes chapters on roll bonding, equal channel angular pressing, autofrettage, friction stir processing/welding, magnetic pulse welding, and riveting – processes used to strengthen and join a variety of materials for lightweight applications and sustainable manufacturing. The contents of this book will be useful to researchers and practitioners alike.