DISTRIBUTION A. Approved for public release; distribution unlimited.
EZ-SB-13-002 Page 1 of 15
Number: EZ-SB-13-002
Date: 26 February 2013
Subject: Correlating Durability Analysis to Unanticipated Fatigue Cracks in Metallic
Structure
References:
1) DAU Program Managers Tool Kit, Fourteenth Edition, April 2008.
2) AFRL-ML-WP-TR-2007-4113, Investigation and Root Cause Analysis Guideline for
Undetected Cracking Incidents In Safety-of-Flight Aircraft Structure, January 2007.
3) MIL-STD-1530C, Aircraft Structural Integrity Program, 18 April 2002.
4) Structures Bulletin EN-SB-11-001, Guidance on Correlating Finite Element Models
to Measurements from Structural Ground Tests, 24 June 2011.
5) Structures Bulletin EN-SB-09-001, Methodology for Determination of Equivalent
Flight Hours and Approaches to Communicate Usage Severity, 15 June 2009.
Background and Purpose:
Many operational aircraft have experienced unanticipated structural fatigue cracking. In
some cases, the engineering analysis was inaccurate and lacked sufficient fidelity to
predict the location and length of the fatigue crack. This Structures Bulletin identifies
sources of possible errors in the structural engineering disciplines, each of which
provides input analyses to the predictions. Guidelines for each discipline are provided
to use in the correlation process for unpredicted fatigue cracking in metallic aircraft
structure.
Structures Bulletin
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