USAF Characteristic K Approach: A Robust Tool for Predicting Fatigue Crack Growth under Various Underload Spectra-Reference-Cited by-同舟云学术

USAF Characteristic K Approach: A Robust Tool for Predicting Fatigue Crack Growth under Various Underload Spectra

Published:2024-07-04 Issue:13 Volume:17 Page:3303
ISSN:1996-1944
Container-title:Materials
language:en
Short-container-title:Materials

Author:

Tiwari Kushagra¹²³^ORCID,Alankar Alankar¹,Singh Raman R. K.²^ORCID,Jones Rhys²⁴^ORCID

Affiliation:

1. Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India

2. Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia

3. IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai 400076, India

4. ARC Industrial Transformation Training Centre on Surface Engineering for Advanced Materials, Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia

Abstract

This paper forms part of an ongoing investigation into the tools required in linear elastic fracture mechanics (LEFM) for evaluating the durability of components designed for limited life replacement. In this study, we demonstrate that the USAF ‘Characteristic K’ method, when combined with the Hartman–Schijve adaptation of the NASGRO crack growth formula, can predict the impact of underloads on the propagation of small cracks in aluminum alloy AA7050-T7451 with reasonable accuracy. The published da/dN versus ΔK small crack growth curves associated with five specific underload spectra are examined. It is found that, in each case, there is reasonably good agreement between the predicted and the measured curves. To the best of the author’s knowledge, this paper is the first to highlight the ability of the USAF Characteristic K approach, when coupled with the Hartman–Schijve equation, to reasonably accurately predict the growth of small cracks subjected to a range of underload spectra.

Funder

US Army International Technology Center, Indo-Pacific (ITC–IPAC), Tokyo

Publisher

MDPI AG

Link

https://www.mdpi.com/1996-1944/17/13/3303/pdf

Reference47 articles.

1. Under Secretary of Defense (2024, April 13). Acquisition and Sustainment, Directive-Type Memorandum (DTM)-19-006-Interim Policy and Guidance for the Use of Additive Manufacturing (AM) in Support of Material Sustainment. Pentagon: Washington, DC, USA, Available online: https://oldcc.gov/sites/default/files/news/Directive-type-Memorandum.pdf.

2. US Army Directive 2019-29 (2024, April 13). Enabling Readiness and Modernization through Advanced Manufacturing. Secretary of the Army, Pentagon: Washington, DC, USA. Available online: https://armypubs.army.mil/epubs/DR_pubs/DR_a/pdf/web/ARN19451_AD2019-29_Web_Final.pdf.

3. Structures Bulletin EZ-SB-19-01 (2024, February 15). Durability and Damage Tolerance Certification for Additive Manufacturing of Aircraft Structural Metallic Parts. Available online: https://daytonaero.com/usaf-structures-bulletins-library/.

4. McMichael, E., Frazier, W., and NAVAIR Additive Manufacturing (2024, January 04). Joint Federal Aviation Administration–Air Force Workshop on Qualification/Certification of Additively Manufactured Parts (DOT/FAA/TC-16/15), Available online: http://www.tc.faa.gov/its/worldpac/techrpt/tc16-15.pdf.

5. (2016). Department of Defense Standard Practice Aircraft Structural Integrity Program (ASIP) (Standard No. MIL-STD-1530D). Available online: http://everyspec.com/MIL-STD/MIL-STD-1500-1599/MIL-STD-1530D_55392/.