The effect of spectrum variations and changes in flight sequence on crack growth in 2024 T351 Alclad sheet of 2 mm and 8 mm thickness

This memorandum presents results of crack propagation tests on notched Alclad 2024-T351 sheet specimens. Two thicknesses were investigated (2 mm and 8 mm), as well as various spectrum modifications and the effect of clustering of severe flights within the test load sequence.