Towards a methodology for the practical applications of the EIFS (Equivalent Initial Flaw Size) concept

Abstract

This work intends to introduce a probabilistic approach for the crack propagation analysis. It presents a methodology that is based on the distribution of the initial flaw size a0. Departing from fatigue test results for specific structural components, an estimation of the initial flaw distribution is obtained, and from this distribution it becomes possible to establish the appropriate initial flaw size for crack propagation analysis for the chosen statistical distribution, such as Weibull or Log-normal. The methodology allows to apply different values of a0 for different components or structural details, reflecting the quality of the manufacturing process for the item evaluated. Two examples of practical applications of the EIFS concept are presented, corresponding to lugs and shear joints usually used for aerospace applications.

Keywords

• EIFS
• fatigue
• damage tolerance
• Weibull distribution
• Log-normal distribution