Download or read book Potential Drop Method for Measuring Fatigue Crack Growth written by A. E. CARDEN and published by . This book was released on 1973 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: IN FATIGUE CRACK GROWTH (FCG) EXPERIMENTS TWO OF THE ESSENTIAL MEASUREMENTS ARE CRACK LENGTH AND CYCLE NUMBER. CRACK LENGTH MEASUREMENT GENERALLY HAS THE LEAST PRECISION AND IS THE MOST EXPENSIVE TO OBTAIN SINCE IT IS USUALLY VISUALLY OBSERVED AND MANUALLY RECORDED. SEVERAL ATTEMPTS HAVE BEEN MADE TO AUTOMATE THE MEASUREMENT AND RECORDING OF THE CRACK LENGTH BUT THE PRECISION WAS LOW WHEN THE CRACK LENGTHS ARE SMALL. A POTENTIAL DROP METHOD DEVELOPED BY MARKOCHEV HAS BEEN APPLIED TO FCG AT ELEVATED TEMPERATURE ON CN SHEET AND CT 2T SPECIMENS WITH GOOD RESULTS. A DIVIDER CIRCUIT GIVES THE RATIO OF THE POTENTIAL DROP NEAR THE CRACK TIP TO THAT IN A SHUNT. OUTPUT IS THEREFORE INSENSITIVE TO CURRENT LEVEL. THE DERIVATIVE OF THE OUTPUT VERSUS CRACK LENGTH IS CONSTANT FROM THE INITIAL CRACK LENGTH TO ABOUT 1/2 A/W. WITH OPERATIONAL AMPLIFIERS AND A MILLIVOLT RECORDER, CRACK LENGTH VERSUS CYCLE NUMBER CAN BE CONTINUOUSLY RECORDED. THE THRESHOLD LEVEL FOR FCG CAN BE MUCH MORE PRECISELY DETERMINED. INCUBATION PERIODS FOR FCG ARE CLEARLY OBSERVED AFTER OVERLOADS. FCG OF 10 TO THE 8TH POWER IN/CYCLE ARE EASILY DEFINED. THE THRESHOLD DELTA K FOR INCOLOY WAS DETERMINED TO BE ABOUT 4 KSI(IN) 1/2 IN LESS THAN 60 HOURS OF TESTING. WITH VISUAL OBSERVATION THE THRESHOLD LEVEL WAS JUDGED TO BE ABOUT 8 KSI(IN) 1/2 IN ABOUT 300 HR OF TEST TIME. THE LOWEST CRACK GROWTH RATE IN THE VISUAL METHOD WAS ABOUT 10 TO THE MINUS 7 IN/CYCLE.
Download or read book A High Sensitivity Potential Drop Technique for Fatigue Crack Growth Measurements written by Graham Clark and published by . This book was released on 1979 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the design features of a highly sensitive and accurate system for monitoring the growth of fatigue cracks in laboratory specimens of various geometries. The system is based on the potential-drop method which utilizes the electrical resistance changes associated with fatigue crack growth through the specimen cross-section to detect crack length increments of a few micrometers. The technique is suitable for automation, and tests may be completed with a minimum amount of operator interference. A computer-based data-processing method is described, and the performance of the system in measuring both absolute crack length and crack growth rate is evaluated.
Download or read book Determination of Fatigue Crack Growth Rate by the Potential Drop Method Set up and Calibration written by O. Vosikovsky and published by . This book was released on 1975 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Crack Measurement written by Kenneth James Marsh and published by . This book was released on 1991 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determining the Potential Drop Calibration of a Fatigue Crack Growth Specimen Subject to Limited Experimental Observations written by PC. McKeighan and published by . This book was released on 1994 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Six separate calibration techniques are applied to potential drop (PD) and crack length data from 23 experimental datasets. Five of the techniques use limited experimental input gained during precracking and after test completion to derive the coefficients associated with the calibrations. The datasets include SE(B) and M(T) specimens, fatigue crack growth (FCG) tests and foil analog simulations as well as various aluminum alloys and steel. A comparison of the calibration techniques is undertaken in terms of crack length and the subsequent effect on stress intensity factor errors. The best calibration techniques using two PD and crack length data pairs are the two-point modified and post-test corrected Johnson's equation. Using these methods, 21 of the 23 tests satisfy a criterion based on an acceptable ±2% mean variation in stress intensity factor. If a statistical assessment of the data is made, only 30 to 35% of the tests satisfy this criterion. Finally, the crack length prediction errors that result from the different calibrations can typically cause a 15 to 30% variation in FCG rate da/dN at a given ?K level. This difference is found to be primarily due to errors in the ?K calculation.
Download or read book Fatigue Testing and Analysis written by Yung-Li Lee and published by Elsevier. This book was released on 2011-04-18 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue Testing and Analysis: Theory and Practice presents the latest, proven techniques for fatigue data acquisition, data analysis, and test planning and practice. More specifically, it covers the most comprehensive methods to capture the component load, to characterize the scatter of product fatigue resistance and loading, to perform the fatigue damage assessment of a product, and to develop an accelerated life test plan for reliability target demonstration. This book is most useful for test and design engineers in the ground vehicle industry. Fatigue Testing and Analysis introduces the methods to account for variability of loads and statistical fatigue properties that are useful for further probabilistic fatigue analysis. The text incorporates and demonstrates approaches that account for randomness of loading and materials, and covers the applications and demonstrations of both linear and double-linear damage rules. The reader will benefit from summaries of load transducer designs and data acquisition techniques, applications of both linear and non-linear damage rules and methods, and techniques to determine the statistical fatigue properties for the nominal stress-life and the local strain-life methods. - Covers the useful techniques for component load measurement and data acquisition, fatigue properties determination, fatigue analysis, and accelerated life test criteria development, and, most importantly, test plans for reliability demonstrations - Written from a practical point of view, based on the authors' industrial and academic experience in automotive engineering design - Extensive practical examples are used to illustrate the main concepts in all chapters
Download or read book The Risk Management of Safety and Dependability written by W Wong and published by Elsevier. This book was released on 2010-04-16 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: The issue of risk should be embedded into the mindset of every engineer and manager to improve safety and dependability. Companies can be held accountable through law when a gross failing in health and safety management has fatal consequences. Here risk management, the organisational structure required and the main factors needed for its successful execution are explored. What risks must be managed as a legal requirement? How is risk quantified? What methods can be used to reduce risk? Such questions are addressed, alongside case histories of disasters to illustrate failures in risk management.In an easy-to-read and accessible way, The risk management of safety and dependability presents the key factors involved in successful risk management, so that even non-experts in small and medium-sized organisations, as well as engineers and managers, can apply sound safety and dependability principles. - Complies with the recommendations of the Engineering Technology Board - Assesses ways of recognising hazards and procedures for reducing risk in the design of processes, plant and machinery - Provides detailed accounts of three major disasters and describes the lessons to be learnt in relation to risk management
Download or read book The AC potential drop method written by Manfred Horstmann and published by . This book was released on 1993 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The AC Potential Drop Method written by Manfred Horstmann and published by . This book was released on 1993 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Current Research on Fatigue Cracks written by Tsuneshichi Tanaka and published by . This book was released on 1987 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Automated Test Methods for Fracture and Fatigue Crack Growth written by W. H. Cullen and published by ASTM International. This book was released on 1985 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Measurement of Crack Length and Shape During Fracture and Fatigue written by C. J. Beevers and published by . This book was released on 1980 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanics of Fatigue Crack Closure written by Wolf Elber and published by ASTM International. This book was released on 1988 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Stable Crack Growth Including Detection of Initiation of Growth Using the DC Potential Drop and the Partial Unloading Methods written by K. H. Schwalbe and published by . This book was released on 1985 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Automated Test Methods for Fatigue Crack Growth and Fracture Toughness Tests on Irradiated Stainless Steels at High Temperature written by BAJ Schaap and published by . This book was released on 1985 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: An automated system for fatigue crack growth and fracture toughness measurements has been developed for irradiated stainless steels tested at temperatures up to 925 K. The system, including a microcomputer, is based on the d-c potential-drop technique for crack extension measurements. Specimens of the compact-tension type are used for the experiments. A description is given of the potential-drop method and the automated data acquisition system. The method of collecting N-a data pairs is given as well as the calculation and analysis of the fatigue crack growth rate (da/dN) and stress-intensity factor (?K). The measurement of load, deflection, and crack extension data to determine the J-versus-?a curves is also discussed.
Download or read book Mechanics of Materials 2 written by E.J. Hearn and published by Elsevier. This book was released on 1997-11-25 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important subjects for any student of engineering or materials to master is the behaviour of materials and structures under load. The way in which they react to applied forces, the deflections resulting and the stresses and strains set up in the bodies concerned are all vital considerations when designing a mechanical component such that it will not fail under predicted load during its service lifetime.Building upon the fundamentals established in the introductory volume Mechanics of Materials 1, this book extends the scope of material covered into more complex areas such as unsymmetrical bending, loading and deflection of struts, rings, discs, cylinders plates, diaphragms and thin walled sections. There is a new treatment of the Finite Element Method of analysis, and more advanced topics such as contact and residual stresses, stress concentrations, fatigue, creep and fracture are also covered. Each chapter contains a summary of the essential formulae which are developed in the chapter, and a large number of worked examples which progress in level of difficulty as the principles are enlarged upon. In addition, each chapter concludes with an extensive selection of problems for solution by the student, mostly examination questions from professional and academic bodies, which are graded according to difficulty and furnished with answers at the end.
Download or read book Standard Test Method for Measurement of Fatigue Crack Growth Rates written by American Society for Testing and Materials. Committee E08 on Fatigue and Fracture and published by . This book was released on 2008 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
