A rectangular plate in biaxial stress (see figure) is subjected to normal stresses (x = 90 MPa

Question:

A rectangular plate in biaxial stress (see figure) is subjected to normal stresses (x = 90 MPa (tension) and (y = - 20 MPa (compression). The plate has dimensions 400 ( 800 ( 20 mm and is made of steel with E = 200 GPa and v = 0.30.
(a) Determine the maximum in-plane shear strain ymax in the plate.
(b) Determine the change (t in the thickness of the plate.
(c) Determine the change (Vin the volume of the plate?