SAFE LIFE OF CRACKED STRUCTURAL ELEMENTS

This paper presents work completed with the principal objective of determining the frequency of the inspection necessary to ensure the safety of a structural element, which is subjected to cyclic loading, as a function of the first inspectable crack size and of the crack growth rate. Established fracture mechanics theory has been used as a starting point and the crack growth rate equation is integrated for finite sheets, for which the geometry correction factor has to be taken into account. Since analytical integration is not possible, it is performed numerically. Thus, the crack growth is studied in real elements under fatigue, considering the critical limit represented by the fracture toughness of the material. Additionally, the process is related to the material constants m and C and to the loading conditions.