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Engineering

Fatigue Crack Growth in Aluminum Stiffened Panels Under Pressurization Cycles

Quick fact

Pressurization cycles are one of the primary drivers of fatigue crack growth in fuselage skin, causing cracks that can grow slowly over many flights. Stiffeners, like stringers and frames, can act as crack stoppers, but the interaction between skin and stiffener is complex and critical for safety.

Why this is interesting

Every time an airliner climbs to cruising altitude, its fuselage expands slightly, and when it lands, it contracts. Imagine doing that thousands of times—what does that repeated stretching do to the aluminum skin?