Download or read book Fatigue Crack Growth from Compression Pre Cracks written by Meghan Borz and published by . This book was released on 2014 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compression pre-crack method can be used to develop near-threshold fatigue crack growth rates much quicker than the ASTM standard load shed method. The compression pre-crack method is faster than the standard method and eliminates load history effects that are of concern when the standard method is used. However, crack growth developed using the compression pre-cracking approach is susceptible to different load history effects. A suite of tests using the compression pre-crack method that were performed on AISI 9310 steel are presented in this paper. An approach for identifying the critical crack growth increments required to develop valid data is presented, and the effects of three potential mechanisms are evaluated. For these tests, the residual stress field resulting from the initial compression field appears to be the more important effect on crack growth behavior. Crack growth increments measured from the notch tip that are 2.5 times larger than the size of the plastic zone resulting from the compression pre-cracking are required in order to develop valid data on the fatigue crack growth rate.
Download or read book The Use of Compression Precracking Constant Amplitude CPCA Test Method to Obtain Near threshold Fatigue Crack Growth Behavior in AA7075 T7351 written by Dustin Henry McKnight and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Traditionally, pre-cracking has been performed under tension-tension loading, followed by a load reduction scheme to obtain fatigue crack growth rate data in the near threshold regime. These data have been shown to exhibit load history effects due to remote crack closure. An alternative test method has been developed to minimize these load history effects. This test procedure uses compression pre-cracking to initiate a crack, followed by constant amplitude loading to grow the crack to failure. Compression-compression (C-C) loading as a means of forming a starter crack for fatigue crack growth is a relatively new concept. Cracks grown under C-C loading emanate from the notch tip due to a tensile residual stress field formed during the unloading cycle. The subsequent constant amplitude steady-state crack growth is free of load history effects, after crack growth beyond several compressive plastic zone sizes, and therefore will give a better steady-state representation of the near-threshold regime. A more in-depth examination at this phenomenon is performed herein.
Download or read book The Use of Compression Precracking Constant Amplitude CPCA Test Method to Obtain Near threshold Fatigue Crack Growth Behavior in AA7075 T7351 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Traditionally, pre-cracking has been performed under tension-tension loading, followed by a load reduction scheme to obtain fatigue crack growth rate data in the near threshold regime. These data have been shown to exhibit load history effects due to remote crack closure. An alternative test method has been developed to minimize these load history effects. This test procedure uses compression pre-cracking to initiate a crack, followed by constant amplitude loading to grow the crack to failure. Compression-compression (C-C) loading as a means of forming a starter crack for fatigue crack growth is a relatively new concept. Cracks grown under C-C loading emanate from the notch tip due to a tensile residual stress field formed during the unloading cycle. The subsequent constant amplitude steady-state crack growth is free of load history effects, after crack growth beyond several compressive plastic zone sizes, and therefore will give a better steady-state representation of the near-threshold regime. A more in-depth examination at this phenomenon is performed herein.
Download or read book Load History Effects Resulting from Compression Precracking written by JA. Newman and published by . This book was released on 2005 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compression precracking (CPC) has seen renewed interest as a possible alternative procedure for generating fatigue crack growth threshold data with minimal load history effects, but recent testing confirms results from the literature that compression precracking does induce load history effects through residual stresses that influence subsequent fatigue crack growth test data. Using the CPC method, specimens are precracked with both maximum and minimum compressive loads. Compressive yielding occurs at the crack-starter notch, resulting in a local tensile residual stress field through which the fatigue crack must propagate. Although the tensile residual stress field contributes to the driving force for precracking, it also introduces the possibility of history effects that may affect subsequent fatigue crack growth. The tensile residual stress field elevates the local driving force at the crack tip, promoting higher crack growth rates than would be expected from the applied loading. This paper presents three-dimensional finite element results and experimental data for compact tension specimens that characterize the load history effects induced by compression precracking. The analysis results indicate that for low tensile loading levels near the threshold region, the residual stresses cause the calculated crack tip driving force to increase from the applied driving force by 25% or more. In addition, significant crack growth of about two times the estimated plastic zone size is needed to grow away from the residual stress field and reduce the calculated crack tip driving force to within 5% of the applied driving force. Experimental results show that growth of about two to three times the estimated plastic zone size is necessary to establish steady growth rates under constant ?K loading for the materials and loading levels evaluated. Constant ?K testing following compression precracking will demonstrate when residual stress effects are no longer significant and will ensure consistent growth rates.
Download or read book Fatigue Crack Growth Thresholds Endurance Limits and Design written by J. C. Newman and published by ASTM International. This book was released on 2000 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Contains 24 papers from the November, 1998 symposium of the same name, sponsored by the ASTM Committee E8 on Fatigue and Fracture, and presented by Newman and Piascik (both of the NASA Langley Research Center). The papers focus on such areas as fatigue-crack growth threshold mechanisms, loading and specimen-type effects, analyses of fatigue-crack-growth-threshold behavior, and applications of threshold concepts and endurance limits to aerospace and structural materials. Annotation copyrighted by Book News, Inc., Portland, OR.
Download or read book Fatigue and Fracture Mechanices written by Steven R. Daniewicz and published by ASTM International. This book was released on 2005-09 with total page 591 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Kth by Compression Pre Cracking in a Structural Steel written by D. Regazzi and published by . This book was released on 2011 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The traditional experimental procedures used to generate thresholds (known as "?K-decreasing" and "constant Kmax") have been challenged because it seems they affect the experimental results, sometimes in a non conservative way. In order to fix this problem, different experimental procedures ("compression pre-cracking constant amplitude" and "compression pre-cracking load reduction" (CPLR)) based on a compression-compression pre-cracking of fracture mechanics specimens have been proposed. Up till now, such procedures are not yet wide-spread between fracture mechanics experimentalists. In particular, due to the recent introduction, CPLR has been applied only to few cases: Al alloys, Ti alloys, and high strength steels (ultimate tensile strength>1300 MPa), all in the shape of M(T) or C(T) specimens subjected to positive stress ratios. The present paper deals with the application of these novel "compression pre-cracking" procedures, with particular attention to CPLR, to the unexplored and technically very important case of the structurally mild A1N steel grade (very commonly used to produce European railway axles) in the shape of SE(B) specimens subjected to stress ratios varying between -2 and 0.85.
Download or read book Strength Failure and Crack Evolution Behavior of Rock Materials Containing Pre existing Fissures written by Sheng-Qi Yang and published by Springer. This book was released on 2015-06-05 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has following unique features that distinguish it from other works from the same area: 1) Investigates the influence of fissure geometry on strength failure and crack evolution behaviour of real rock material; 2) Analyzes the effect of pre-experiment high-temperature treatment on fracture mechanical behaviour of rock material with a single fissure or two parallel fissures; 3) Compares quantitatively simulated results using discrete element modelling and experimental results of fracture mechanical behaviour of rock material with two fissures; 4) Constructs the relationship between crack evolution processes and acoustic emission distribution of pre-fissured rock material under entire deformation; and 5) Discusses the crack evolution mechanism of pre-fissured rock material with respect to different confining pressures. This book can become the reference for technicians in the field of geotechnical engineering, mining engineering and geology engineering. At the same time, this book can be regarded as a good reference for scientific researchers carrying out fissured rock mechanics and correlated specialties.
Download or read book Fatigue of Materials written by S. Suresh and published by Cambridge University Press. This book was released on 1998-10-29 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a leading researcher in the field, this revised and updated second edition of a highly successful book provides an authoritative, comprehensive and unified treatment of the mechanics and micromechanisms of fatigue in metals, non-metals and composites. The author discusses the principles of cyclic deformation, crack initiation and crack growth by fatigue, covering both microscopic and continuum aspects. The book begins with discussions of cyclic deformation and fatigue crack initiation in monocrystalline and polycrystalline ductile alloys as well as in brittle and semi-/non-crystalline solids. Total life and damage-tolerant approaches are then introduced in metals, non-metals and composites followed by more advanced topics. The book includes an extensive bibliography and a problem set for each chapter, together with worked-out example problems and case studies. This will be an important reference for anyone studying fracture and fatigue in materials science and engineering, mechanical, civil, nuclear and aerospace engineering, and biomechanics.
Download or read book Fatigue and Fracture of Weldments written by Uwe Zerbst and published by Springer. This book was released on 2018-12-11 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive and thorough guide to those readers who are lost in the often-confusing context of weld fatigue. It presents straightforward information on the fracture mechanics and material background of weld fatigue, starting with fatigue crack initiation and short cracks, before moving on to long cracks, crack closure, crack growth and threshold, residual stress, stress concentration, the stress intensity factor, J-integral, multiple cracks, weld geometries and defects, microstructural parameters including HAZ, and cyclic stress-strain behavior. The book treats all of these essential and mutually interacting parameters using a unique form of analysis.
Download or read book Non Linear Fracture written by W.G. Knauss and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: From time to time the International Journal of Fracture has presented special matters thought to be of interest to its readers. In previous issues, for example, Dr. H.W. Liu as Guest Editor assembled a series of review papers dealing with fatigue processes and characteristics in metals and non-metals (December 1980 and April 1981). Five years ago Guest Editor W.G. Knauss collected works dealing with dynamic fracture (March and April 1985). Continuing this policy, Dr. W.G. Knauss and Dr. A.J. Rosakis of the California Institute of Technology as Guest Editors have now organized an extensive set of papers concerning the influence of non-linear effects upon the mechanics of the fracture process. This collection is based upon contributions to a relatively small international Symposium on Non Linear Fracture Mechanics held under the auspices of the International Union of Theoretical and Applied Mechanics (IUTAM) and convened at the California Institute of Technology in March 1988. It should be noted that although the description of non-linear fracture inherently encompasses a strong material science component, this aspect is not heavily emphasized in the ensuing papers due to the intentional focus upon mechanics. Volume 42 of the International Journal of Fracture will therefore, in successive issues, deal respectively with topics in (1) Damage, (2) Interfaces and Creep, (3) Time Dependence, and (4) Continuum Plasticity. On behalf of the editors and publishers, I wish to express our appreciation to Dr. Knauss, Dr. Rosakis, and their colleagues for their collective efforts.
Download or read book Static Creep Micro Macro Fracture Mechanics of Brittle Solids written by Xiaozhao Li and published by Springer Nature. This book was released on 2024-01-13 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers a large amount of recent research results on this topic to better understand the static creep micro–macro fracture mechanics in brittle solids (e.g., glass, ceramic, concrete, ice, and rock). To be precise, this is about to explore the effects of the external factors of stress paths, water content, seepage pressure, dynamic disturbance, thermal treated temperature, and the internal factors of crack angle, size, recovery, and nucleation coalescence on the static creep fracture mechanical properties in brittle solids. This book provides important theoretical support in evaluation for long-term lifetime in the brittle solid engineering (e.g., deep underground engineering, architecture engineering, aerospace engineering, and mechanical manufacturing engineering).
Download or read book Determination of Kth by Compression Pre Cracking in a Structural Steel written by M. Carboni and published by . This book was released on 2009 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shock Compression of Condensed Matter 1991 written by S.C. Schmidt and published by Elsevier. This book was released on 2016-07-29 with total page 1103 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers collected together in this volume constitute a review of recent research on the response of condensed matter to dynamic high pressures and temperatures. Inlcuded are sections on equations of state, phase transitions, material properties, explosive behavior, measurement techniques, and optical and laser studies. Recent developments in this area such as studies of impact and penetration phenomenology, the development of materials, especially ceramics and molecular dynamics and Monte Carlo simulations are also covered. These latest advances, in addition to the many other results and topics covered by the authors, serve to make this volume the most authoritative source for the shock wave physics community.
Download or read book Fatigue Crack growth and Crack Closure Behavior of Aluminum Alloy 7050 and 9310 Steel Over a Wide Range in Load Ratios Using Compression Pre cracking Test Methods written by Talal Mehdi Senhaji and published by . This book was released on 2016 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue-crack-growth-rate tests were conducted on compact tension specimens made of 7050-T7451 aluminum alloy and 9310 steel. Compact tension specimens were tested over a wide range of load ratios (0.1 ≤ R ≤ 0.9) to generate crack-growth-rate data from threshold to near fracture. Three methods were used to generate near threshold data. A crack-closure analysis was performed on both materials using the FASTRAN crack-closure model. The crack-growth-rate data for each material correlated very well and each collapsed onto a nearly unique curve in the low- and mid-rate regimes using the strip-yield model in the FASTRAN life-prediction code. For the 7050 alloy, a constraint factor of a = 1.8 was required, while for the 9310 steel a = 2.5 worked very well in correlating the test data over a very wide range in R values and rates from threshold to near fracture.
Download or read book FAA NASA International Symposium on Advanced Structural Integrity Methods for Airframe Durability and Damage Tolerance written by Charles E. Harris and published by . This book was released on 1994 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Materials Structure Micromechanics of Fracture VII written by Pavel andera and published by Trans Tech Publications Ltd. This book was released on 2013-11-15 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collection of selected, peer reviewed papers from the 7th International Conference on Materials Structure & Micromechanics of Fracture (MSMF-7), July 1-3, 2013, Brno, Czech Republic. Volume is indexed by Thomson Reuters CPCI-S (WoS). The 186 papers are grouped as follows: Chapter 1: Plenary Keynotes; Chapter 2: Atomistic Studies on Deformation and Fracture; Chapter 3: Deformation and Fracture Models Based on Crystal Defects Behaviour; Chapter 4: Mathematical Modeling Microstructure, Deformation and Fracture; Chapter 5: Multiaxial Deformation and Fracture, Experiment and Modeling; Chapter 6: Nanomaterials: Technology, Properties and Modeling; Chapter 7: Biomaterials: Deformation, Fracture, Modeling; Chapter 8: Surface and Interface Microstructure and Properties; Chapter 9: Advanced Experimental and Theoretical Methods for Microstructure Investigation; Chapter 10: Experimental Studies on the Relation between Microstructure and Mechanical Properties; Chapter 11: Micromechanisms of Fracture and Fatigue (ESIS TC2)
