Relation between Flexural modulus and Youngs modulus to find Poisson's ratio

Hello!

If the material is ISOTROPIC LINEAR ELASTIC, it is perfectly defined by TWO ELASTIC CONSTANTS, such as the longitudinal modulus of elasticity "E" (YOUNG's modulus) and the lateral contraction coefficient "nu" (POISSON's coefficient).

In LINEAR ELASTICITY problems, the tangential modulus of elasticity "G" also usually appears, but it IS NOT INDEPENDENT of the previous two, rather the three are linked by the relationship:

G = E/(2*(1+nu))

You can see the explanation of this in my tutorial:
Teoría de la Elasticidad Lineal - Parte 16

Yield strength has no direct relationship to E, nu, and G. You will find many steels, for example, with similar E and nu, but very different yield strengths (and yield and rupture limits).

I'm not sure what you mean by "tensile modulus and flexural modulus" but, if they are related to the response of a piece to tension, for example, if it has a constant cross section, it has "as a piece" a "tensile/compression stiffness " equal to E*A/L and of such a value you will not be able to solve or find the Poisson's ratio. The same as, for example, an embedded part subjected to bending by a load at its end, has a "flexural stiffness" equal to 3*E*I/L^3. You will not be able to obtain the Poisson's ratio from this relationship either.
Now, if "tensile modulus and flexural modulus" refers to the properties of a beam section, these are purely geometric relationships (depending on the shape and size of the cross section) and have no relationship with the material (nor with E, nu, G).

Kind regards!