Composite Flexural Strength Problem

Dear All,

While I am conducting analysis on ACP pre, I wanted to verify the prepreg's flexural strength in the database. I modeled the 3 point bending system and applied the required displacement but the result is quite different from the flexural strength in the datasheet. I suppose that failure occurs when the stress exceeds the compressive strength of the outer fiber. Could you please help me to overcome this problem?

Answers

  • sharveysharvey San Diego, CAMember

    Hello @kahramanyu,

    Thanks for posing this question. So are you seeing the stress result from Ansys less than or greater than that of the datasheet? Also when you say flexural strength in the database, which database? The strengths that are input for the material data are not flexural, but rather the tensile and shear. Can you please clarify?

    Failure can occur in compression or tension, or even shear (if the specimen is short) What constitutes failure in the datasheet will depend on what standard was used. It is possible to run the model in Ansys and see that failure is predicted when the extreme fiber reaches the allowable stress level (tension or compression) but since that stress is only experienced by a small fraction of the specimen (since there is a through thickness variation) using that initial failure would under predict the ultimate strength in flexure. But if you wanted to prevent any damage, you would use that first ply failure. When flexural strength is reported, there is generally a spec that is referenced so how it was determined can be understood.

    If you can provide more details, that could help. Thank you!

    Regards,

    Sean

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