Characterization of Cracking and Crack Growth Properties of the C5a Aircraft Tie-box Forging

Characterization of Cracking and Crack Growth Properties of the C5a Aircraft Tie-box Forging PDF

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-08-27

Total Pages: 36

ISBN-13: 9781726238670

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Detailed destructive examinations were conducted to characterize the integrity and material properties of two aluminum alloy (7075-T6) horizontal stabilizer tie box forgings removed.from US. Air Force C5A and C5B transport aircraft. The C5B tie box forging was, found to contain no evidence of cracking. Thirteen cracks were found in the CSA, forging. All but one of the cracks observed in the C5A component were located along the top cap region (one crack was located in the bottom cap region). The cracks in the C5A component initiated at fastener holes and propagated along a highly tunneled intergranular crack path. The tunneled crack growth configuration is a likelv result of surface compressive stress produced during peening of the .forging suijace. The tie box forging, fatigue crack growth, fracture and stress corrosion cracking (SCC) properties were characterized. Reported herein are the results of laboratory air, fatigue crack growth tests and 95% relative humidity SCC tests conducted using specimens machined from the C5A, forging. SCC test results revealed that the C5A, forging material was susceptible to intergranular environmental assisted cracking: the C5A forging material exhibited a SCC crack-tip stress-intensity factor threshold of less than 6 MPadn. Fracture toughness tests revealed that the C5A forging material exhibited a fracture toughness that was 25% less than the C5B forging. The C5A forging exhibited rapid laboratory air fatigue crack growth rates having a threshold crack-tip stress-intensity factor range of less than 0.8 MPa sup m. Detailed fractographic examinations revealed that the, fatigue crack intergranular growth crack path was similar to the cracking observed in the C5A tie box forging. Because both fatigue crack propagation and SCC exhibit similar intergranular crack path behavior, the damage mechanism resulting in multi-site cracking of tie box forgings cannot be determined unless local cyclic stresses can be quantified.Piascik, Robert S. a.

Aging of U.S. Air Force Aircraft

Aging of U.S. Air Force Aircraft PDF

Author: National Research Council

Publisher: National Academies Press

Published: 1997-09-30

Total Pages: 124

ISBN-13: 0309174473

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Many of the aircraft that form the backbone of the U.S. Air Force operational fleet are 25 years old or older. A few of these will be replaced with new aircraft, but many are expected to remain in service an additional 25 years or more. This book provides a strategy to address the technical needs and priorities associated with the Air Force's aging airframe structures. It includes a detailed summary of the structural status of the aging force, identification of key technical issues, recommendations for near-term engineering and management actions, and prioritized near-term and long-term research recommendations.

USAF Damage Tolerant Design Handbook

USAF Damage Tolerant Design Handbook PDF

Author: J. P. Gallagher

Publisher:

Published: 1984

Total Pages: 1380

ISBN-13:

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The handbook provides specific background data and justification for the detailed requirements of MIL-A-83444 and provides guidelines and state-of-the-art analysis methods to assist contractor and USAF personnel in complying with the intent of the specification and in solving cracking problems, in general, for metallic aircraft structures. Cf. Report Documentation Page.

Crystal Plasticity Finite Element Methods

Crystal Plasticity Finite Element Methods PDF

Author: Franz Roters

Publisher: John Wiley & Sons

Published: 2011-08-04

Total Pages: 188

ISBN-13: 3527642099

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Written by the leading experts in computational materials science, this handy reference concisely reviews the most important aspects of plasticity modeling: constitutive laws, phase transformations, texture methods, continuum approaches and damage mechanisms. As a result, it provides the knowledge needed to avoid failures in critical systems udner mechanical load. With its various application examples to micro- and macrostructure mechanics, this is an invaluable resource for mechanical engineers as well as for researchers wanting to improve on this method and extend its outreach.

Nondestructive Characterization of Materials II

Nondestructive Characterization of Materials II PDF

Author: Jean F. Bussière

Publisher: Springer Science & Business Media

Published: 2013-03-14

Total Pages: 750

ISBN-13: 1468453386

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The possibility of nondestructively characterizing the microstruc ture, morphology or mechanical properties of materials is certainly a fascinating subject. In principle, such techniques can be used at all stages of a material's life - from the early stages of processing, to the end of a structural component's useful life. Interest in the subject thus arises not only from a purely scientific point of view but is also strongly motivated by economic pressures to improve productivity and quality in manufacturing, to insure the reliability and extend the life of existing structures. The present volume represents the edited papers presented at the Second International Symposium on the Nondestructive Characterization of Materials, held in Montreal, Canada, July 21-23, 1986. The Proceedings are divided into eight sections, which reflect the multidisciplinary nature of characterizing materials nondestructively: Polymers and Composites, Ceramics and Powder Metallurgy, Metals, Layered Structures/Adhesive Bonds/Welding, Degradation/Aging, Texture/ Anisotropy, Stress, and New Techniques. Invited papers by R. Hadcock of Grumman Aircraft Systems, R. Cannon of Rutgers University, H. Yada of Nippon Steel and R. Bridenbaugh of Alcoa review respectively the processing of polymer matrix composites, ceramics, steel and aluminum, emphasizing the need for material property sensors to improve process and quality control. Two other invited papers, one by A. Wedgwood of Harwell and the other by P. Holler of the IzFP in Saarbrucken review state of the art techniques to characterize particulate matter and metals respectively.

Nondestructive Characterization of Materials IV

Nondestructive Characterization of Materials IV PDF

Author: J.F. Bussière

Publisher: Springer Science & Business Media

Published: 2013-11-11

Total Pages: 506

ISBN-13: 1489906703

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There is a great deal of interest in extending nondestructive technologies beyond the location and identification of cracks and voids. Specifically there is growing interest in the application of nondestructive evaluation (NOEl to the measurement of physical and mechanical properties of materials. The measurement of materials properties is often referred to as materials characterization; thus nondestructive techniques applied to characterization become nondestructive characterization (NDCl. There are a number of meetings, proceedings and journals focused upon nondestructive technologies and the detection and identification of cracks and voids. However, the series of symposia, of which these proceedings represent the fourth, are the only meetings uniquely focused upon nondestructive characterization. Moreover, these symposia are especially concerned with stimulating communication between the materials, mechanical and manufacturing engineer and the NDE technology oriented engineer and scientist. These symposia recognize that it is the welding of these areas of expertise that is necessary for practical development and application of NDC technology to measurements of components for in service life time and sensor technology for intelligent processing of materials. These proceedings are from the fourth international symposia and are edited by c.o. Ruud, J. F. Bussiere and R.E. Green, Jr. . The dates, places, etc of the symposia held to date area as follows: Symposia on Nondestructive Methods for TITLE: Material Property Determination DATES: April 6-8, 1983 PLACE: Hershey, PA, USA CHAIRPERSONS: C.O. Ruud and R.E. Green, Jr.

Nondestructive Materials Characterization

Nondestructive Materials Characterization PDF

Author: Norbert G. H. Meyendorf

Publisher: Springer Science & Business Media

Published: 2013-11-21

Total Pages: 435

ISBN-13: 3662089882

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With an emphasis on aircraft materials, this book describes techniques for the material characterization to detect and quantify degradation processes such as corrosion and fatigue. It introduces readers to these techniques based on x-ray, ultrasonic, optical and thermal principles and demonstrates the potential of the techniques for a wide variety of applications concerning aircraft materials, especially aluminum and titanium alloys. The advantages and disadvantages of various techniques are evaluated.

The Practical Use of Fracture Mechanics

The Practical Use of Fracture Mechanics PDF

Author: D. Broek

Publisher: Springer

Published: 1988-10-31

Total Pages: 544

ISBN-13:

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This book is about the use of fracture mechanics for the solution of practical problems; academic rigor is not at issue and dealt with only in as far as it improves insight and understanding; it often concerns secondary errors in engineering. Knowledge of (ignorance of) such basic input as loads and stresses in practical cases may cause errors far overshadowing those introduced by shortcomings of fracture mechanics and necessary approximations; this is amply demonstrated in the text. I have presented more than three dozen 40-hour courses on fracture mechanics and damage tolerance analysis, so that I have probably more experience in teaching the subject than anyone else. I learned more than the students, and became cognizant of difficulties and of the real concerns in applications. In particular I found, how a subject should be explained to appeal to the practicing engineer to demonstrate that his practical problem can indeed be solved with engineering methods. This experience is reflected in the presenta tions in this book. Sufficient background is provided for an understanding of the issues, but pragamatism prevails. Mathematics cannot be avoided, but they are presented in a way that appeals to insight and intuition, in lieu of formal derivations which would show but the mathematical skill of the writer.

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