How to determine the flexural rigidity of a composite

[kaizen.moto]

Hi there,

I need help about how to solve the flexural rigidity (D) of a composite. For instance, if I have two plies of a plate each with different material properties, i.e. ply 1 has different Young modulus from ply 2. Therefore, how can I determine the value of the overall D of the plate.
How can I smear the D?

Example:

ply 1 has E1 = 200 MPa, E2 = 30 MPa and v = 0.2
ply 2 has E1 = 400 MPa, E2 = 40 MPa and v = 0.3

using the D = Eh / 12(1-v^2), how can I smear the two different properties into a single value of D?

Please let me know. Thanks

 

[Navin A S]

.The answer to your question is that you need to calculate the flexural rigidity of each ply separately, then calculate the weighted average of the two individual flexural rigidities to get the overall flexural rigidity of the composite plate. The weighted average is calculated by taking the sum of the individual flexural rigidities (D1 and D2) multiplied by their respective area fractions (A1 and A2). The formula is as follows: D = (D1 * A1 + D2 * A2) / (A1 + A2)To calculate the individual flexural rigidities, use the formula D = Eh / 12(1-v^2), where E is the Young's modulus and v is the Poisson's ratio. For example, D1 = (200 MPa * 12(1 - 0.2^2)) / 12 = 160 MPa D2 = (400 MPa * 12(1 - 0.3^2)) / 12 = 266.67 MPa If the area fraction of ply 1 is 0.5 and the area fraction of ply 2 is 0.5, then the overall flexural rigidity of the composite plate can be calculated using the formula above: D = (160 MPa * 0.5 + 266.67 MPa * 0.5) / (0.5 + 0.5) = 213.335 MPa Hope this helps!