Affiliations: Department of Aeronautics and Space Engineering,
Politecnico di Torino, Italy
Note: [] Corresponding author: Salvatore Brischetto, Department of
Aeronautics and Space Engineering, Politecnico di Torino, Corso Duca degli
Abruzzi, 24, 10129 Torino, Italy. Tel.: +39 011 564 6869; Fax: +39 011 564
6899; E-mail: salvatore.brischetto@polito.it
Abstract: The free vibration analysis of one-layered and two-layered metallic
cylindrical shell panels is evaluated in this work. The free frequency values
are investigated for both thermo-mechanical and pure mechanical problems.
Thermo-mechanical frequencies are calculated by means of a fully coupled
thermo-mechanical model where both the displacement and temperature are primary
variables in the considered governing equations. Pure mechanical frequencies
are obtained from a mechanical model where the effect of the temperature field
is not included in the stiffness matrix and the displacement is the only
primary variable of the problem. The inclusion of the thermal part in the
stiffness matrix gives larger frequencies. Both thermo-mechanical and pure
mechanical models are developed in the framework of Carrera's Unified
Formulation (CUF) in order to obtain several variable kinematic models. Both
equivalent single layer and layer wise approaches are considered for
multilayered shells. The use of refined two-dimensional theories for shells
permits the evaluation of the effects of the thermo-mechanical coupling for
lower and higher order modes, higher frequency values, multilayered
configurations, thick and thin shells and several values of the radius of
curvature of the shell geometry. It has mainly been concluded that the
thermo-mechanical coupling is not influenced by the curvature of the shells,
therefore, the main conclusions already given for the plate geometry are here
confirmed: – the thermo-mechanical coupling is correctly determined if
both the thermal and mechanical parts are correctly approximated; – it is
small for each investigated case; – it influences the various vibration
modes in different ways; – it has a limited dependence on the considered
case, but this dependence vanishes if a global coupling is considered.
Keywords: Carrera's Unified Formulation, thermo-mechanical coupling, fully coupled thermo-mechanical models, refined theories, free vibrations of shells, global thermo-mechanical effect
