Download or read book Fracture Mechanics written by Ravinder Chona and published by ASTM International. This book was released on 1993 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings of the 23rd National Symposium on Fracture Mechanics, held in College Station, Texas, June 1991, present a broad overview of the current state of the art in fracture mechanics research. Following the Swerdlow Lecture (Structural Problems in Search of Fracture Mechanics Solutions by

Download or read book Development of a Fatigue Crack Growth Rate Specimen Suitable for a Multiple Specimen Test Configeration written by FR. Deshayes and published by . This book was released on 1993 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new experimental approach developed by fatigue crack growth rates can be determined for multiple specimens tested in series. This involves a geometry such that the response to cyclic loading in each specimen is mutually independent. Relationships between the stress intensity factor, compliance, and crack length and between direct-current potential drop and crack length have been analytically evaluated for the proposed specimen geometry. An appropriate side-groove depth that avoided crack deviation from the intended plane of extension was determined experimentally, and an analytical expression that accounted for reduced thickness in the crack plane was verified. Calibration curves between crack length and compliance and between crack length and potential drop were experimentally verified as well, and the stress intensity-crack length characteristics for the specimen were confirmed by comparing da/dN-?KI curves with those for conventional C(T) specimens. A customized, five specimen frame was designed and fabricated in conjunction with a 98-kN MTS actuator and interfaced with a commercially available control system, the hardware and software of which were modified to accommodate multiple-specimen control and data acquisition. The utility of the proposed specimen and test procedure is discussed within the context of threshold and near-threshold crack growth rate determinations where long test times are normally required for data development, particularly for low cyclic frequency applications such as nuclear and offshore.

Download or read book Development of a Multiple Specimen Test Methodology for Fatigue Crack Growth Rate Determination written by Frederic R. Deshayes and published by . This book was released on 1991 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anomalous Fatigue Crack Growth Data Generated Using the ASTM Standards written by J. C. Newman and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ASTM standard for fatigue crack growth, E 647, was co-developed by industry and government in the late 1970s to define a standard procedure for generating material crack growth behavior under a variety of loading conditions. The standard specifies tolerances on laboratory procedures, specimen configurations to generate material characterization information of a high integrity. Recent research developing fatigue crack growth rate data has uncovered significant issues with the standard test method and specimen configurations. The data generated has been largely dependent on specimen configuration, i.e., M(T) and C(T) specimens produce very different crack growth rate curves; C(T) specimens of different sizes do not generate the same material response; and finally, the development of steady-state, as defined using constant ?K testing, does not agree with the data generated with the standard ASTM test method. Therefore, in this paper the authors present data that does not lend confidence in the integrity of the standard C(T) specimen tested using the ASTM standard method and investigate causes for the observed anomalous crack growth rate behavior.

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 Development of a Constant K Specimen for Materials Testing written by P. Huculak and published by . This book was released on 1986 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study is presented of a constant stress intensity factor specimen comprising four circular cutouts. The results of fatigue crack growth tests, compliance measurements, and a finite element formulation show that minor modifications to a center cracked tension specimen lead to constancy in the stress intensity factor as a function of crack length. The basic geometry can also be repeated in a stacked configuration in order to test multiple cracks in a single setup.

Download or read book Fatigue Crack Growth Measurement and Data Analysis written by S. J Hudak and published by ASTM International. This book was released on 1981 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Subsize Specimens for Fatigue Crack Growth Rate Testing of Metallic Materials written by JF. Stubbins and published by . This book was released on 2002 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the potential for obtaining reliable fatigue crack growth data from miniature notched bar specimens in three-point bend loading is examined. These specimens, at 2.0 mm wide by 0.8 mm thick by 7.9 mm long, are substantially smaller than any existing fatigue crack growth specimens. This work describes the development of subsize specimen fatigue crack growth rate test techniques using these miniature bar specimens. Fatigue crack growth data are reported for three alloys, 304L SS, Alloy 718 and Mod. 9Cr-1Mo steel. The data obtained using the subsize specimens compare favorably to crack growth rate data obtained on ASTM standard size specimens. The fracture surface microstructures of the subsize and standard size specimens are compared to show the similarities of the crack growth mechanisms in the two specimen configurations. Since three different materials were tested, it is possible to draw conclusions about the limitations of using these extremely small specimens in terms of material yield and ultimate strength and other standard tensile properties.

Download or read book Some Observations Regarding Specimen Size Criteria for Fatigue crack Growth Rate Testing written by Lee A. James and published by . This book was released on 1977 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of a Crack Growth Rate Test for Quality Control written by and published by . This book was released on 1977 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: A test method has been developed which reliably and inexpensively provides the fatigue crack growth rate of a material sample at any given stress intensity level. The method employs a notched three point bend bar, typically 4 i/4 in. x 1/2 in. x 1/4 in., in a controlled displacement amplitude test mode. The specimen/test system is configured such that a constant stress intensity amplitude exists over the central region of the test specimen. Due to the unique attributes of a displacement controlled constant K test specimen, no visual or COD measurements of crack length are required for the crack growth rate measurement. An autographic record of load amplitude versus cycles exhibits a straight line portion, the slope of which provides a measurement of the central region crack growth rate. The test is simple enough so that a well trained quality control laboratory technician can perform it employing about one hour of his time to set it up, run the test and analyze the result. Capability has been demonstrated by comparing the results of 137 tests using the newly developed method with crack growth rate data generated employing compact tension geometry samples.

Download or read book Development of a Circumferentially Throughwall Cracked Tube Specimen for Fatigue Crack Growth Rate Tests written by BA. Young and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes the development of a nonstandard specimen geometry for fatigue crack growth rate studies. Most fatigue crack growth rate data, available in open literature, for Alloy 690 and Alloy 600 were developed using standard, thick section C(T) specimens. Recently a need arose to study a circumferentially throughwall cracked tube specimen. The goal of the development was to use this tube specimen to determine any effects of section thickness or grain size on corrosion enhancement of fatigue crack growth rates in a simulated pressurized water reactor (PWR) primary side environment. Along with the final specimen geometry, the stress intensity equation and crack length monitoring equation are discussed. The stress intensity equation was converted to a standard polynomial equation in order to use a conventional automated fatigue crack growth rate software package. Symmetry arguments were made to justify the use of direct current potential drop (DCPD) and the use of the standard Johnson's equations for measuring crack lengths. Also, some discussions of the validity requirements for this geometry are presented such as stress intensity limits to remain with linear elastic fracture mechanics (LEFM) bounds and crack length limits to avoid excess bending stresses. A baseline test program was conducted on Alloy 690 tube specimens in ambient air and these results were compared with literature data. Also, a sensitivity investigation was preformed to determine the error between the polynomial equations developed and the actual equations in literature. The results of this study confirmed that a circumferentially cracked tube specimen could produce valid fatigue crack growth rate data.

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 Experimental Cycle Analysis of Fatigue Crack Growth in Compact Type Specimen Geometries written by T. A. Prater and published by . This book was released on 1982 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Basic Material s Data for Evaluating Crack Growth Life written by RJ. Bucci and published by . This book was released on 1979 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture toughness, fatigue crack growth rate, and sustained load crack growth data comprise a basic package of materials property information used in predicting growth of cracks by fracture mechanics methods. Accurate analysis requires carefully developed laboratory results using various simple specimen configurations to describe these properties. A contributing factor to variability in life prediction is the lack of consistent procedures for obtaining and reporting this information for use in design. Though a standard does exist for direct fracture toughness determinations (ASTM Method E 399), standards for subcritical crack growth measurement are in various stages of development. Accuracy of life prediction is further confounded by judgment required of the analyst in selecting the most appropriate test and interpreting material property data for use in the computational methodology.

Download or read book Variability in Fatigue Crack Growth Rate Testing written by S. J. Hudak and published by . This book was released on 1974 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mode II Fatigue Crack Growth Specimen Development written by RJ. Buzzard and published by . This book was released on 1986 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel Mode II test specimen has been developed that has potential application in understanding phenomena associated with mixed-mode fatigue failures in high performance aircraft engine bearing races. The attributes of the specimen are as follows: it contains one single-ended notch, which simplifies data gathering and reduction; the fatigue crack grows in-line with the direction of load application; a single axis test machine is sufficient to perform testing; and the Mode I component is vanishingly small.

Download or read book Investigation of Fatigue Crack Growth in Ti 8A1 1Mo 1V duplex annealed Specimens Having Various Widths written by C. M. Hudson and published by . This book was released on 1967 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: