Download or read book Dynamic Fracture Toughness Evaluation by Measurement of CTOD Crack Tip Opening Displacement written by William N Sharpe (Jr) and published by . This book was released on 1988 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantification of the dynamic fracture toughness of structural materials is essential to a wide range of problems - from nuclear accidents to ordnance applications. However, the difficulties associated with accurate measurements of cracks under dynamic loading are considerable. Thus there are no standardized procedures and few reliable results. This work describes a systematic study of the dynamic fracture toughness of SAE-01 tool steel, 4340 and HY100 steels and a tungsten, using the ISDG (Interferometric Strain/Displacement Gage) system which has very high frequency resolution. The major advantage of the method is that information is obtained very close to the crack tip, so that stress wave loading effects are accounted for. A detailed error analysis gives an uncertainty of -10% to +20% in the determination of fracture toughness, which compares with + or - 20% for published work.
Download or read book Dynamic Crack Tip Opening Displacement CTOD Measurements with Application to Fracture Toughness Testing written by JM. Shapiro and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crack-tip opening displacement (CTOD) measurements were made 100 üm behind the crack tip on standard three-point bend specimens using a laser-based interferometric technique. Four materials (SAE-01 steel, 4340 steel, HY-100 steel, and tungsten) were tested at loading rates ranging from quasi-static (K ? 1 MPa• m1⁄2/s) to dynamic (K ? 106 MPa • m1⁄2/s).
Download or read book The Crack Tip Opening Displacement in Elastic Plastic Fracture Mechanics written by K.H. Schwalbe and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sponsored by Studiengesellschaft zur Förderung der Kern- energieverwertung im Schiffbau und Schiffahrt e.V. (KEST), Hamburg/Stiftung Volkswagenwerk, Hannover
Download or read book Standard Test Method for Crack Tip Opening Displacement CTOD Fracture Toughness Measurement written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamic Fracture Toughness Papers written by Welding Institute and published by . This book was released on 1977 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Dynamic Fracture Toughness of Ductile Materials written by EM. Hackett and published by . This book was released on 1988 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this study was to demonstrate the applicability of a J-based approach to fracture characterization of ductile alloys subjected to dynamic loading. Three-point-bend [SE(B)] fracture specimens of a high-strength steel were subjected to impact loading in a drop tower, and appropriate strains and displacements were measured to allow estimation of J. A finite element analysis of these experiments was conducted to evaluate the applicability of a J-based fracture characterization scheme and to provide guidance for the experimental measurements. The concept of a transition time was introduced to provide an estimate of the time during which the controlling crack-tip field [Hutchinson-Rice-Rosengren (HRR) field] stabilizes. The paper demonstrates that for fracture times greater than the transition time, J can be accurately evaluated by the quasi-static deep-crack formulation. For the case of the steel SE(B) specimen geometry used for this study, the transition time was approximately 300 s. The finite-element analysis indicated that the net moment carried by the remaining ligament of the specimen could be evaluated by measurements of the flexural and stresses at the quarter-span position on the SE(B) specimen. This was verified experimentally in drop tower experiments utilizing strain gages at the quarter-span position. These results were found to compare well with a load estimation scheme based on a full bridge of strain gages attached to the tension and compression surfaces of the SE(B) specimen. The load accuracy obtained using the full bridge was also found to be insensitive to crack extension and plasticity at the crack tip. Methods of determining the crack initiation point in these dynamic experiments were evaluated. It was found that the double capacitance crack-opening displacement (COD) gage used in the experiments provides an accurate estimate of the crack initiation point.
Download or read book Dynamic Fracture Toughness Measurements on Small Charpy Specimens 97 A Preliminary Study written by WN. Sharpe and published by . This book was released on 1994 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: A technique for measuring dynamic fracture toughness on small specimens is described and preliminary data are presented. Dynamic crack tip opening displacements (CTODs) are measured with laser interferometry over times as short as 10 ?s. The measured displacement is converted to stress intensity values via the equations of linear elastic fracture mechanics and the peak value obtained is taken as the dynamic fracture toughness.
Download or read book Fracture Mechanics written by J. P. Gudas and published by ASTM International. This book was released on 1990 with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers from the 21st National Symposium on Fracture Mechanics, held in Annapolis, Md., June 1988, present new work in elastic-plastic fracture, dynamic fracture, transition fracture in steels, micromechanical aspects of the fracture process, computational mechanics, fracture mechanics testing, and a
Download or read book Advances in Fracture Research written by K. Salama and published by Elsevier. This book was released on 2013-10-22 with total page 3063 pages. Available in PDF, EPUB and Kindle. Book excerpt: Held every four years, the International Congress on Fracture is the premier international forum for the exchange of ideas between scientists and engineers involved in producing and using materials resistant to fracture and fatigue. This major six-volume work which forms the proceedings of the Seventh International Congress on Fracture therefore provides the most comprehensive account available of the current status of research into fracture and fatigue, and the application of this knowledge to the design, fabrication and operation of materials and structures. As such, it will be an essential reference for materials scientists and mechanical, structural, aeronautical and design engineers with an interest in fracture and its prevention.
Download or read book Crack Tip Opening Displacement CTOD Toughness Evaluation by ASTM E 1290 and BS5762 written by S. Bhattacharya and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: ASTM Committee E-24 on Fracture has recently standardized the crack tip opening displacement (CTOD) measurement method. Three major differences between the ASTM E 1290-89 method and British Standard BS5762:1979 are outlined, and the influence of these differences on the critical crack initiation CTOD value is studied. The study is based on a typical fatigue crack and slow crack growth front profile. A difference of up to 6% in the CTOD values between the two standards, irrespective of the slow crack growth size, was found in the present study. However, a marginal ditterence of only 2% in the initiation CTOD value could be observed for the slow crack growth situation considered.
Download or read book Local Approach to Dynamic Fracture Toughness Evaluation written by T. Ochiai and published by . This book was released on 2000 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture toughness properties of structural steels of 490-MPa strength class and weld metals under dynamic loading are studied in the light of the near crack tip stress fields. The loading rate in toughness tests range from 0.1 to 500 mm/s. The near-tip stress fields are analyzed by 3D-FEM considering the strain rate effect on the flow properties of materials. Temperature rise caused by high-speed plastic deformation is also included in the FE analysis. The critical CTOD at brittle fracture initiation decreases when increasing the loading rate. This is due to the elevation of a local stress near the crack tip. The local approach is applied to the dynamic fracture toughness evaluation. It is shown that the brittle fracture resistance evaluated in terms of the Weibull stress, an integrated stress over a highly stressed region near the crack tip, is a material property independent of the loading rate. Based on the Weibull stress fracture criterion, the dynamic fracture toughness can be predicted from static toughness results. An engineering procedure to estimate the loading rate effect on the fracture toughness is also presented.
Download or read book ASTM E1290 07 El Standard Test Method for Crack tip Opening Displacement CTOD Fracture Toughness Measurement written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Fracture Research Brittle fracture Ductile fracture Dynamic fracture written by and published by . This book was released on 1989 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fracture Toughness Evaluation by R curve Methods written by and published by ASTM International. This book was released on 1973 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book R Curve Generation and CTOD Evaluation Considering Maximum Crack Growth Size and Parabolic Crack Front written by S. Bhattacharya and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The standard methods of estimating the average size of the slow crack growth region as described in BS 5762 (Crack Opening Displacement (COD)) and ASTM E 1290 (Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement) are cumbersome, painstaking, time consuming, and dependent on several factors; e.g., section thickness, the nature of crack front profile, and the number of measurements. Often errors are introduced in determining the average crack size which in turn affect the determination of critical CTOD value.
Download or read book A Comparison of J Integral and CTOD as Fracture Toughness Parameters written by TL. Anderson and published by . This book was released on 1988 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The J-integral and the crack-tip opening displacement (CTOD) are widely used throughout the world to measure the fracture toughness of structural materials. There are many similarities between these two parameters, as well as a number of important differences. Because of these differences, the CTOD parameter tends to be more conservative when applied to structures.
Download or read book Shallow Crack Fracture Mechanics Toughness Tests and Applications written by Michael Graham Dawes and published by Woodhead Publishing. This book was released on 1992-01-15 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the last decade there has been an increasing awareness that use of standards deeply notched fracture mechanics test specimens can result in substantial over-or-under-assessments of the real fracture toughness associated with shallow surface cracks.
