ESDU 76013 gives graphs enabling the maximum deflection and the maximum direct and shear stresses to be found in initially flat simply-supported panels. The method assumes the face plates have the same Poisson's ratio but they can have different thicknesses and moduli of elasticity. The curves were calculated from elastic small deflection theory assuming the face plates to be thin and the core infinitely stiff in the through-thickness direction. These assumptions will be valid for panel thickness/face plate thickness greater than 6, for panel length/panel thickness greater than 10, and for deflection/panel thickness less than 0.5.