Definition
The property of a material that allows it to absorb energy and deform under sudden load without fracturing. A tough material resists tearing, cracking, or breaking when struck or bent.
Plain English
How well a material takes a hit or a sudden load without cracking or breaking. Tough materials bend or stretch a bit instead of snapping.
Context Anchor
Seen in aircraft materials, structures, maintenance, and repair discussions when comparing how metals, plastics, or composite parts handle loads and impacts.
Derivation
From Old English 'toh,' meaning strong, firm, or able to resist breaking. The everyday sense of 'tough' as 'hard to damage' carries directly into the engineering meaning.
Why Pilots Care
Aircraft parts must absorb impacts and stresses without catastrophic fracture.
Intuition Check
Toughness does not mean the same thing as hardness. A hard material resists scratching or denting; a tough material resists cracking or breaking when it is hit, bent, or twisted.
Example Sentence 1
The landing gear components are made from a steel alloy chosen for its toughness, so they absorb hard landings without cracking.
Example Sentence 2
Technicians checked the toughness of the replacement skin panel before installation.