25 th ICAF Symposium – Rotterdam, 27–29 May 2009 DAMAGE TOLERANCE PHILOSOPHY FOR BONDED AIRCRAFT STRUCTURES C.D. Rans 1 and R.C. Alderliesten 1 1 Delft University of Technology, Delft, 2629 HS, the Netherlands Abstract: This paper presents a damage tolerant philosophy for bonded aircraft structures and repairs. The approach presented utilizes a strain energy release rate approach for predicting bond line delamination growth and a stress intensity factor approach for predicting adherent cracking. The novel addition to the method lies within the coupled analysis of bond line and adherent failure using a displacement compatibility approach. An overview of the methodology and the necessary experimentation to implement it is presented. Additionally, two case studies are presented to illustrate the power and performance of the proposed methodology. NOMENCLATURE Symbol δ displacement [mm] γ shear strain τ shear stress [MPa] a adherent half-crack length [mm] b bond line delamination length [mm] C Paris relation coefficient E Young’s modulus [MPa] G T total strain energy release rate [MPa mm] G I mode I strain energy release rate [MPa mm]