Improved efficient zigzag and third order theories for circular cylindrical shells under thermal loading

Abstract

An improved efficient zigzag theory (IZIGT) and an improved third order theory (ITOT) are presented for laminated circular cylindrical shells and shell panels under thermal loading. The transverse deflection is approximated nonuniformly to explicitly account for the transverse strain due to temperature. The inplane displacements are modelled in ITOT to have global cubic variation across the thickness and are modelled in IZIGT to have additional layerwise zigzag linear variation. The number of primary variables is reduced to 5 by imposing conditions on transverse shear at outer and inner surfaces for ITOT and also at layer interfaces for IZIGT. The governing equations and boundary conditions are derived using the principle of virtual work. The IZIGT, ZIGT, ITOT and TOT are assessed in comparison with exact 3D thermoelasticity solution for simply supported shells and shell panels of different lay-ups. The comparison reveals that IZIGT and ITOT are an improvement over ZIGT and TOT respectively, and in general, IZIGT is more accurate than ITOT for thermal loading.