Aerospace Structures

Synthetic program:

l'insegnamento rappresenta il naturale proseguimento del corso di Fondamenti di meccanica strutturale fornendo una conoscenza approfondita sulle tipologie delle strutture aerospaziali e sui metodi di calcolo utilizzati per il loro dimensionamento e verifica. Vengono inoltre affrontati i temi della meccanica del continuo non lineare e dei metodi di risoluzione approssimati. I principali argomenti trattati sono: Le strutture aeronautiche. Le travi nelle strutture aerospaziali. Meccanica del continuo. Modelli strutturali. Soluzioni approssimate. Elementi finiti lineari. Applicazione di Elementi finiti al calcolo nonlineare.

1. Aerospace structures:
Introduction. Overview of spacecraft and aircraft structures.

2. Continuum mechanics:
General formulation of continuum mechanics. Stress and strain measures. Balance equations. Elastic problem for small strain and displacements. Variational principles.

3. Beams in aerospace structures:
Beam models.

3. Stressed skin constructions:
Aerospace beams, monocoque and semi-monocoque schemes. Ribs and frames. Simplified structural analysis of junctions; types of structural connections.

4. Plates:
Kirchhoff and Mindlin plate theories and their extension to composite materials. Evaluation of stresses and strains for isotropic and composite elements. Sandwich structures.

5. Finite element method:
Ritz's method and residual weighted methods: applications to one- and two-dimensional structures. The Finite Element Method for the linear structural analysis: residual vector; stiffness matrix; loads and boundary conditions; properties and convergence of the solution.

6. Instability:
Stability of elastic equilibrium, bifurcations, limit points. Buckling criteria. Approximate and exact solutions for the buckling of beams, plates and shells. Imperfection sensitivity.