Best Spatial Distributions of Shell Kinematics Over 2D Meshes for Free Vibration Analyses
- PDF / 2,012,899 Bytes
- 16 Pages / 595.276 x 790.866 pts Page_size
- 76 Downloads / 166 Views
ORIGINAL ARTICLE
Best Spatial Distributions of Shell Kinematics Over 2D Meshes for Free Vibration Analyses Marco Petrolo1 · Erasmo Carrera1 Received: 10 March 2020 / Revised: 24 April 2020 / Accepted: 29 April 2020 © AIDAA Associazione Italiana di Aeronautica e Astronautica 2020
Abstract This paper proposes a novel approach to build refined shell models. The focus is on the free vibrations of composite panels, and the node-dependent-kinematics is used to select shell theories node-wise. The methodology shown in this work can provide at least two sets of information. First, it optimizes the use of shell models by indicating the minimum number of refined models to use. Then, it highlights which areas of the structures are more vulnerable to non-classical effects. Moreover, by varying various problem features, e.g., boundary conditions, thickness, and stacking sequence, the influence of those parameters on the modelling strategy is evaluated. The results suggest the predominant influence of thickness and boundary conditions and the possibility to improve the quality of the solution via the proper use of the refinement strategy. Keywords Shell · Finite element method · Node dependent kinematics
1 Introduction Shell theories depend on variable distributions along the thickness direction, and such distributions define the number of degrees of freedom (DOF) per node. Shell elements in commercial codes rely on the classical theories of structures [1–6] and the maximum number of DOF is six, namely, three displacements and rotations. Classical models are reliable if the structure is thin, there are no local effects, and inplane stress and transverse displacements are of interest. Concerning composite structures, several phenomena fall beyond the prediction capabilities of classical models [7, 8]. Examples are high transverse deformability and anisotropy, edge-effects, local distortions, higher-order oscillations, cracks, and contacts as transverse stresses and normal stretch become primarily important. Other examples of critical problems are those with multifield interactions such as thermal problems in which the material characteristics can change significantly and in an anisotropic manner.
* Marco Petrolo [email protected] Erasmo Carrera [email protected] 1
Department of Mechanical and Aerospace Engineering, MUL2 Group, Turin, Italy
The improvement of classical models has to consider shear and normal transverse stresses, and variations of the displacement field at the interface between two layers with different mechanical properties, i.e., the zig-zag effect [9–20]. As a general guideline, the Koiter recommendations, i.e., the inclusion of both transverse shear and axial stress in refined theories, remain a valuable guideline that should lead the development of shell theories [11, 21, 22]. The present paper deals with the free vibration analysis of composite shells via FEM. In the last decades, many contributions have been published concerning this topic as shown by Qatu’s comprehensive reviews [23
Data Loading...
