This paper presents a set of results from an experiment that is designed to evaluate a damage detection approach for
through-thickness fatigue cracks emanating from a rivet hole in a high-performance aircraft bulkhead. Because fatigue
cracks have been found through depot-level visual-inspections at the same location in several aircraft bulkheads, a "hot-spot"
approach to monitor this area with Lamb waves generated from surface-mounted lead ziconate titanate (PZT)
transducers is evaluated. Detecting these fatigue cracks is challenging because the cracks propagate through an area of
restricted geometry - a small plate-like area surrounded by thick webbing - which results in the interference of reflected
wave components with the direct path wave components when using a pitch-catch approach. To minimize this
interference, time-of-flight windows are applied to remove the reflected signals, and to increase probability of detection,
Lamb wave mode tuning is used. Finally, to make the crack easier to detect, various static loads are applied to open the
crack, but new challenges are presented when attempting to detect damage under a static load.