Definition
To form a sheet of metal or other material into a series of parallel ridges and grooves that increase its stiffness and resistance to bending without adding significant weight.
Plain English
To shape a flat sheet into a wavy, ridged pattern so it becomes much stiffer than it was when flat.
Context Anchor
Seen in aircraft construction and maintenance when describing metal skin, control surfaces, or structural panels shaped with ridges.
Derivation
From the Latin 'corrugare,' meaning 'to wrinkle' (from 'ruga,' a wrinkle or fold). The wrinkles or folds in the sheet are exactly what give corrugated material its stiffness.
Why Pilots Care
Corrugated skin is a structural feature on some aircraft (notably the Junkers Ju 52 and the Ford Tri-Motor). Pilots and mechanics inspecting these aircraft need to recognize that the ridges are load-bearing and that damage to them affects structural integrity.
Analogy
Think of a flat sheet of cardboard versus the same cardboard with wavy ridges sandwiched inside -- the wavy version is far stiffer for the same amount of material.
Intuition Check
Corrugate does not mean the material is accidentally bent or damaged. Here it means the ridges and grooves were intentionally formed for strength or stiffness.
Example Sentence 1
The mechanic noted that the corrugated skin on the wing of the Ford Tri-Motor adds rigidity without adding much weight.
Example Sentence 2
Early aircraft often used corrugated metal panels because they were light yet rigid enough for flight loads.