An alternative approach for modal analysis of stiffened thin-walled structures with advanced plate elements

Abstract

Nowadays, many vehicles and buildings are built using the structural concept of stiffened structure, in order to achieve greater strength with relatively less material. In the present work, a plate finite element with advanced higher-order kinematic field is proposed for the free-vibration analysis of stiffened thin-walled plate structures. A novel approach is introduced to simplify the modelization and assembling phase for the analysis of stiffened structures. The mechanical continuity between skin and stiffener deformed geometry is automatically verified with the present approach. On the basis of the Principle of Virtual Displacements, Equivalent-Single-Layer and Layer-Wise models related to linear up to fourth order variations of the unknown variables in the thickness direction are treated. The Mixed Interpolated Tensorial Components (MITC) method, in conjunction with the Finite Element Method (FEM), is employed to contrast the shear locking effect. Various stiffener shapes are considered for the assessment of the approach: T shape, double-T shape and Z shape. Several numerical investigations are carried out to validate and demonstrate the accuracy and efficiency of the present plate finite element for the modal analysis of stiffened structures, comparing the present results with those from classical finite element formulations based on solid elements available in commerical software.