Quantifying Spectrum Loading Effects on Fatigue Crack Growth in 7075-T73 Alumiunums

摘要

The combined effects of four variables on calculated spectrum fatigue crack growth (FCG) in 7075-T73 aluminum were compared using an experimental design approach (NASGRO 3.0 adaptation). The four parameters considered were: (1) load interaction, (2) load sequences (rainflow counted low-to-high, rainflow counted and randomized, and rainflow counted high-to-low), (3) crack tip stress state (plane stress versus plane strain) and (4) spectrum type (FELIX-28 helicopter rotor blade spectrum versus F-16 wing-root-bending moment spectrum).