Home Contact Sitemap

DTD Handbook

Handbook for Damage Tolerant Design

  • DTDHandbook
    • About
    • Contact
    • Contributors
    • PDF Versions
    • Related Links
    • Sections
      • 1. Introduction
        • 0. Introduction
        • 1. Historical Perspective on Structural Integrity in the USAF
        • 2. Overview of MIL-HDBK-1530 ASIP Guidance
        • 3. Summary of Damage Tolerance Design Guidelines
          • 0. Summary of Damage Tolerance Design Guidelines
          • 1. Summary of Guidelines
          • 2. Design Category
          • 3. Inspection Categories and Inspection Intervals
          • 4. Initial Damage Assumptions
          • 5. Residual Strength Guidelines
          • 6. Required Periods Of Safe Damage Growth
            • 0. Required Periods Of Safe Damage Growth
            • 1. Slow Crack Growth Structure
            • 2. Fail Safe Multiple Load Path Structure
            • 3. Fail Safe Crack Arrest Structures
          • 7. Illustrative Example Of Guidelines
        • 4. Sustainment/Aging Aircraft
        • 5. References
      • 2. Fundamentals of Damage Tolerance
      • 3. Damage Size Characterizations
      • 4. Residual Strength
      • 5. Analysis Of Damage Growth
      • 6. Examples of Damage Tolerant Analyses
      • 7. Damage Tolerance Testing
      • 8. Force Management and Sustainment Engineering
      • 9. Structural Repairs
      • 10. Guidelines for Damage Tolerance Design and Fracture Control Planning
      • 11. Summary of Stress Intensity Factor Information
    • Examples

Section 1.3.6.2. Fail Safe Multiple Load Path Structure

An initial inspection interval is established to insure detection of any premature primary element failure.  The initial inspection interval is dependent on the particular geometry and degree of inspectability, as given in Table 1.3.5.  The initial inspection interval should not be greater than one half of the time to primary load path failure from the specified initial flaw for primary elements plus one half of remaining time to failure of adjacent structure from its flaw size at the time of primary element failure.  These initial flaw sizes are specified in Section 1.3.4.

Subsequent inspection intervals are also based on the degree of inspectability of the primary element as given in JSSG-2006 Table XXXIV and repeated in Table 1.3.6.