Numerical Analysis of Damaged Stiffened Panels With Respects to Fracture Mechanics

 

Katarina Maksimović

Milutin Janković

Nenad Berić

Vera Nikolić-Stanojević

 

The main and primary structures in airframes are composed of stiffened panels in order to obtain high specific strength. This paper considers the finite element modelling to evaluate the fracture behaviour of cracked thin-walled structural components. The rapid development of computer technology has brought conditions for solving problems increasingly demanding in terms of numerical simulations. In the case of complex and large construction systems exposed to arbitrary loads, including complex boundary conditions, solving differential equations by analytic methods is very difficult or impossible. Then the solution requires using numerical methods, most often, using the finite element method (FEM). To determine stress intensity factors (SIF`s) of cracked thin-walled stiffened panels, singular finite elements are used. In this paper, the effects of the stiffeners on SIF`s are considered. The fatigue crack growth behaviour of 2219-T851 aluminum is characterized by constant-amplitude loading conditions. Fatigue crack growth analyses are performed on the cracked panel using Paris`s and Valker`s crack growth models. Analytical predictions are correlated with the test data.

Key words: thin walled structure, aircraft structure, fracture mechanics, panel, crack, crack growth, numerical analysis, finite element method, singular finite elements, stress intensity factor.