The [+45/-45] laminate described in Problem 7.6 is subjected to a uniaxial force per unit length \(N_{x}=30 \mathrm{MPa} \mathrm{mm}\). Find the resulting stresses and strains in each ply along the \(x\) - and \(y\)-directions.

Problem 7.6 

Show that for symmetric laminates the coupling stiffnesses, \(B_{i j}\), must all be equal to zero.