Does anyone Know how to calculate the average propierties for a multilayer PCB?

Does anyone Know how to calculate the average propierties for a multilayer PCB? I have attemped to find some information about it but I can´t. I usually know the number of layer (e.g 12) the material some of FR4 and other copper and their thickness, I wold like to calculate the average mechanical propierties of the material that I might use for simulation

Regards

SolidworksSimulation