Studies in Composites
Homework 6
1.- Consider an isotropic Al7075 square plate (a=b=0.1 m, thickness =0.01 m). A load q0 = 100e6 Pa is
applied normal to the span of the plate while the plate is simply supported along all edges. Calculate the
deflection of the plate using the Rayleigh –Ritz method and the finite element method.
2.- Repeat the calculation assuming that the plate is actually a stack of four 0.0025 m thick isotropic
lamina.
3.- Consider a specially orthotropic four layer [90/0]S cross ply graphite-epoxy laminate square plate (a=
b=0.1) loaded by a uniform pressure q0 =1e6 Pa normal to the plane of the plate while the plate is
simply supported along all edges. Calculate the deflection of the plate using the Rayleigh –Ritz method
and the finite element method.
Assume lamina thickness = 0.0025 m; and E1 = 148 GPa, E2 = 9.65 GPa, G12 = 4.55 GPa, ν12 =0.3, ν23 =0.6,
q0 = 100e6 Pa
4.- Consider a specially orthotropic four layer [0/45]S cross ply graphite-epoxy laminate square plate (a=
b=0.1) loaded by a uniform pressure q0 =1e6 Pa normal to the plane of the plate while the plate is
simply supported along all edges. Calculate the deflection of the plate using the Rayleigh –Ritz method
and the finite element method.
Assume lamina thickness = 0.0025 m; and E1 = 148 GPa, E2 = 9.65 GPa, G12 = 4.55 GPa, ν12 =0.3, ν23 =0.6,
q0 = 100e6 Pa
5.- Consider a specially orthotropic four layer [+45/-45]S cross ply graphite-epoxy laminate square plate
(a= b=0.1) loaded by a uniform pressure q0 =1e6 Pa normal to the plane of the plate while the plate is
simply supported along all edges. Calculate the deflection of the plate using the Rayleigh –Ritz method
and the finite element method.
Assume lamina thickness = 0.0025 m; and E1 = 148 GPa, E2 = 9.65 GPa, G12 = 4.55 GPa, ν12 =0.3, ν23 =0.6,
q0 = 100e6 Pa