Stiffened Lattice Plates Homogenization Methods for Aerospace Applications

(Title: Stiffened Lattice Plates Homogenization Methods for Aerospace Applications). The scientific community has been drawn to lattice structures due to their high structural efficiency, which has led to numerous studies in the literature. By arranging the material in the three-dimensional space of the structure, these structures can achieve extremely low weights while maintaining high mechanical performance. This is why Lattice Structures have been used in aerospace for several years. Defining the future behavior of any structure in advance during the preliminary design phase is crucial to keep costs and design themes as low as possible. However, the identification of mechanical characteristics of lattice structures requires a significant computational cost due to their complex internal structure. Homogenization methodologies have been introduced in the early stages of design to facilitate the design process thanks to their lower computational costs. This thesis work starts with the introduction of two homogenization methodologies for stiffened plates with different families and geometrical configurations of reticular stiffening structures. In particular, homogenization methods based on Reissner Mindlin’s First Order Shear Deformation Theory and the Thimoshenko First Order Transverse Shear Deformation Theory, called ”Direct Equilibrium Compatibility Method” and ”Energy Equivalence Method” are presented. In addition, Finite Element Analysis and parametric studies are performed on three different configuration of Lattice Plates to validate these methodologies. Finally, a real-life application of an aerospace Lattice Structure is reported. The effectiveness and limitations of these homogenization methods, commonly used in the early stages of lattice-plate structures design for aerospace applications, are highlighted in this study.