Simple and Fast Method to Calculate Shape Factors of Stiffened Panels Repaired with Composites

Abstract

In this paper, a new, simple, and robust method is presented to calculate the shape factor and stress intensity factor (SIF) of cracked stiffened panels in a mode-I condition repaired with a single-side composite patch. For this purpose, huge finite element (FE) analyses are carried out to achieve a simple equation using normalized parameters and a fitting technique for a vast range of repaired stiffened panels. The parametric study was performed using five effective parameters, including crack length, stiffeners and panel moment of inertia, material, and thickness of the composite patch. Using the proposed formulation in this paper, performing the complex and time-consuming FE analyses to calculate the stress intensity factors for such repaired complex components is not necessary. The obtained results are verified using several FE models. The maximum differences between the predicted shape factors using the proposed equation with those obtained from FE analyses are indicated to be approximately 7%, which is acceptable for engineering purposes.