if each ply has a different loading then it'll have a different strain. For example ...
1) unidirectional plies under axial load, all plies have the same load/stress/strain
2) a laminate of 0,+45,-45 plies ... under any load each ply will have different load/stress/strain as permitted by the elasticity of the adhesive.
"Wir hoffen, dass dieses Mal alles gut gehen wird!"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.