Towards the Certification of Bonded Primary Fiber Metal Laminate Structures by Bolted Disbond Arrest Features

A new certification approach for bonded primary Fiber Metal Laminate (FML) structures is investigated: using bolts as Disbond Arrest Features (DAF)s to contain the growth of bond line damages so that they can be found and repaired by inspection before becoming critical. By fatigue testing with coupon specimens and model analysis, it has been demonstrated that reducing the Mode I Strain Energy Release Rate (SERR) is the main driver for arrest. The peak stress associated with a disbond front can initiate adherend fatigue cracks during slow growth. The effect of adherend fatigue cracks on the arrest of disbond growth could not be determined and must be investigated in future work. In the process, a novel quasi-analytical disbond growth model has been developed and validated. An algorithm is developed and verified that utilizes the strain field measured by Digital Image Correlation (DIC) to locate the disbonded region.Aerospace Engineerin