Probabilistic model of the growth of correlated cracks in a stiffened panel

The objective of this paper is to develop a probabilistic model for a stiffened panel subjected to correlated growth of cracks in the stiffener and plate elements. The geometry functions of the correlated cracks in the plate and in the stiffener are defined based on the stress intensity factors calculated by finite element analysis. A validation of the stress intensity factor and the geometry function calculation has been performed for an isolated crack in a plate with a central/edge through thickness crack. The Paris–Erdogan law is used to predict the crack propagation. Monte Carlo simulation is employed to define the statistical descriptors of the crack growth in the stiffened panel under different correlation functions and a probabilistic model of crack size as a function of time are presented adopting a truncated normal distribution to describe the probability density function of the crack size in the plate and in the stiffener. A procedure for the development of a probabilistic crack growth model for a stiffened panel has been proposed, allowing for the existence of multiple cracks both in the stiffeners and in the plate and accounting for the correlation between them. The developed probabilistic model may be used for fatigue crack growth analysis and is suitable for reliability assessment of a stiffened panel subjected to correlated crack growth.