Expansion of cracked fastener holes as a measure for extension of lifetime to repair

This paper presents results of experimental and theoretical investigations about the influence of cold expansion on crack-propagation life of pre-cracked fastener holes in 2024T3 aluminium alloy. Three different types of test specimens with different levels of load transfer and secondary bending and different pre-crack configurations were used. It turned out that these parameters as well as the type of loading (constant amplitude or flight-by-flight) and the initial crack length have a considerable influence on the possible gain in crack-propagation life. (LBF)