acceptance criteria of carbon prepreg material structure

[shyrius]

What is the acceptance criteria for structural prepreg made material. What delamination surface/length is allowed
doc reference could be helpfull

 

[SWComposites]

It depends ... on many things ...

What is the application?
What is the structure?
What is the configuration?
What are the loading conditions and environments?
What are the stress/strain levels?
etc,
etc,
etc,

 

[shyrius]

The application is structural , tubular structure, super quasi configuration, the loading conditions don't now yet,

My question: on what base (standard) should delaminaions/disbonds be rejected?
Are thermal cycles and vibrations test applicable and legitimate for aproval a part with those defects (if it is observed that the rejects does not extend after the environmental tests)?

 

[SWComposites]

on what base (standard) should delaminaions/disbonds be rejected? when the delam size is large enough to a) reduce structural capability below ultimate load, b) grow under operational loads and environments, or c) adversly affect durability, it is rejected.

Are thermal cycles and vibrations test applicable and legitimate for approval of a part with those defects (if it is observed that the rejects does not extend after the environmental tests)? They may be sufficient for some applications (e.g., those with no significant mechanical loads) assuming the test conditions adequately simulate the part operational environment; but those tests will not be sufficient for other applications.

Acceptable delam sizes are typically defined in process specfictions and are validated with appropriate static and fatigue test data, and in some cases with analytical predictions.

If you don't know the structural loads, how can you design the part?