Following is an approximate expression* for the maximum interlaminar normal stress, szz, at an interface position z from the midplane of a symmetric [0=90]S type laminate: and the summation extends...

Following is an approximate expression* for the maximum interlaminar normal stress, szz, at an interface position z from the midplane of a symmetric [0=90]S type laminate:

and the summation extends over all the laminas above the interface position z. This equation is valid for thin laminas in which the variation of in-plane stresses is assumed to be negligible over the thickness of each lamina. Using this approximate expression, compare the maximum interlaminar normal stresses at the midplanes of [0=90=90=0] and [90=0=0=90] laminates.