Multilayer Beam- Flexural Stresses

[NX10user]

Hello,

I'm having a conceptual problem here. I have a multilayer beam that was tested under a 3 point flexural bending using ASTM D7264. The standard provides the formula of flexural stresses for a quasi-isotropic beam where the load "F" from the test is used to calculate stresses. In my case, the beam is asymmetric and hence I have the following questions:

1. Can we still use the same formula "σ=My/L" to calculate the stresses? If not, is there any good way to modify the formula for my case?
2. I have done some research where modification of neutral axes and moments can be done for asymmetric layers, but then how can introduce the variation in elastic constants of each layer?

Please provide me with your valuable input. If you can recommend books/articles that would be very helpful.

BR

 

[rb1957]

even an asymmetric beam has a neutral axis ("y" is measured from the neutral axis)

sections made of different materials are solved with the "rule of mixtures". You convert the section to one material by factoring the other area by E1/E2, solve then convert stresses in the factored area by E2/E1. You should be able to find this in any strength of materials text.

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