Effective Elastic Constants:

The unidirectional lamina is interest of this course. The unidirectional lamina is orthotropic in nature. We know from the 3D constitutive equations that an orthotropic material has 9 independent constants. Further, for a transversely isotropic material there are 5 independent constants. The average or effective constitutive equation for transversely isotropic material is given as below. The transverse isotropy is in plane 2-3.

where ,  are the effective elastic constants of the equivalent homogeneous material.
In this chapter, we are going to see the micromechanical methods to obtain the effective engineering constants that define the above effective elastic constants of the equivalent homogeneous material.