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  • Users: Jnnal
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  1. Jnnal

    Hi, As per the document "Fatigue

    Hi, As per the document "Fatigue evaluation of wing and associated structure on small airplanes. Federal Aviation Administration Rept. DOT-FAA-AFS-120-73-2, Washington DC, 1973.", The total fatigue damage calculation involves Gust, Maneuver, Landing and Taxi and also GAG cycle. In GAG cycle is...
  2. Jnnal

    Scatter factor as per AC 23-13 A

    Thank you all for this lively discussion. My question is related to PART 23 class aircraft landing gear. I am a starter in this area and my understanding/Queries as of now is 1. Fatigue life and damage tolerance life, both have to be established for the structure 2. Landing gear is designed as...
  3. Jnnal

    Scatter factor as per AC 23-13 A

    Thank you
  4. Jnnal

    Scatter factor as per AC 23-13 A

    Related to any literature on how to arrive at the SD or if a particular number for scatter factor is to be used, where can I find it? If we want to certify a product, we have to provide references. It is challenging to convince the authority that we may use 3 or 4 or any other number. Thank you
  5. Jnnal

    Scatter factor as per AC 23-13 A

    Hi, Thank you. Please share any references when you find some time.
  6. Jnnal

    Scatter factor as per AC 23-13 A

    Thank you for your reply. However, AC 23-13 A says about " Standard Deviation (SD) of Log Fatigue Life for Built-up Structures Constructed of Common Structural Metals". How do get these SD. Is it from material test alone. Again, in S-N curve, we may have different SD at different stress levels...
  7. Jnnal

    Scatter factor as per AC 23-13 A

    Hi rb1957, It is given in the 23-13 itself, for various materials, it has been in the range of 14% (Aluminum) to 25% (High strength steel)
  8. Jnnal

    Scatter factor as per AC 23-13 A

    Hi, as per AC 23-13 A, Eq.4 provides a scatter factor to account for the statistical variability inherent in the fatigue performance of built-up structures. As per the same, the standard deviation to be used for high strength steels like one used in landing gear are to be 25% and, the scatter...
  9. Jnnal

    Hi, Recently, I was reading through

    Hi, Recently, I was reading through AC23-13A. The exceedance curves are normalized with Incremental Design Limit Maneuver Load Factor at Maximum Gross Weight (anLff) to get Incremental Maneuver Load Factor at Operating Weight (an). What is the meaning here of the word incremental in anlff? Is...
  10. Jnnal

    Fatigue life calculation - aircraft components - scatter factor and S-N curves

    Hi, I am started to work in the area of aircraft fatigue life estimation and please help me with the following: I have few questions regarding fatigue life estimation of metallic aircraft components. Let say, The life can be computed using S-N curves (from MMPDS) and Miners damage under given...

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