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# Composite Mechanical Properties from ASTM D3039

## Composite Mechanical Properties from ASTM D3039

(OP)
Hi all,

I have been presented with the coupon test results from ASTM D3039 (Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials). The test have been performed on the few laminate lay up with fiber direction on the 0-degree and 90-degree.

How we are going extract the mechanical properties (E1 and E2) for ONE ply lamina from this coupon test results? As far as I know, there is rule of mixture to calculate the longitudinal and transverse modulus (E1 and E2) for ONE ply of lamina. But how to correlate this calculation with the results from the coupon testing that have been performed for a laminate lay up?

Lamina = 1 ply
Laminate = a stack of plies

### RE: Composite Mechanical Properties from ASTM D3039

You use laminated plate theory calculations to predict laminate stiffness given lamina property values (there are many text books with the equations, including Jones, Mechanics of Composite Materials; you can also use google to find laminate analysis codes online). You will need to make educated guesses as to the lamina values, and then adjust those values until you get good predictions for all of the tested laminates. Start with the material supplier data sheets for estimates of the lamina properties.

SW

### RE: Composite Mechanical Properties from ASTM D3039

(OP)
Thanks SWComposites for your suggestion here, to calculate the engineering elastic constants for the laminate. It turns out that the same stiffness for a laminate (Ex, Ey) and lamina (E1, E2) regardless of laminate ply thickness, provided all the orientation are in 0-degree (for Ex = E1) and 90-degree (for Ey = E2).

Pardon for my ignorance, and hopefully this post will help other to understand more the composite materials properties behavior.

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