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AFGROW | DTD Handbook

Handbook for Damage Tolerant Design

  • DTDHandbook
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    • Sections
      • 1. Introduction
      • 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
        • 0. Damage Tolerance Testing
        • 1. Introduction
        • 2. Material Tests
        • 3. Quality Control Testing
        • 4. Analysis Verification Testing
        • 5. Structural Hardware Tests
          • 0. Structural Hardware Tests
          • 1. Test Conditions
          • 2. Initial and Continuing Damage
          • 3. Residual Strength Testing
          • 4. Damage Tolerance Test Articles
          • 5. Evaluation and Interpretation of Test Results
        • 6. References
      • 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 7.5.0. Structural Hardware Tests

The structural hardware tests have two functions: to support the verification of the complete structural design, and to define those areas of the structure that need additional attention.  These tests are scheduled so that there is sufficient time to incorporate structural changes into production aircraft.  In fact, production go-ahead is predicated on completing at least one design lifetime of flight-by-flight loading in the full-scale durability test (see JSSG-2006 paragraph A.  Structural hardware tests include joint tests, component tests, assembly tests, as well as full-scale structural tests.

Examples of variables that may be considered for the study of different design concepts, design details and structural materials are:

·        fastener systems

·        type of joints and joint detail

·        forged versus machined or built-up structure

·        production method

·        reinforcement or tear strap shape, size, and spacing

·        multiple or single load path

·        materials or combination of materials

·        effect of design stress level

The testing of one or more of these variables will not be specifically addressed.  Rather, a discussion of the essential conditions for design development testing for damage tolerance is presented in general.