Engineering Terminology Flashcards
Elastic limit
The stress up to which strain is elastic; if the load is removed, the object will return to its original shape and size. Beyond this point permanent deformation occurs.
Yield Stress
The point at which there is an increase in strain without a corresponding increase in stress (i.e the object suddenly elongates).
Proof Stress
The proof stress is the amount of stress necessary to bring about a certain amount of permanent strain in a material. Proof stress is used as a measure of yield on materials that do not show a marked yield point.
Resilience
The ability of a material to absorb energy, but only up to the elastic limit. The area under the curve in the elastic deformation region represents the resilience of a material.
Toughness
The ability of a material to absorb energy. Tough materials are those capable of absorbing strain energy or the energy of an impact, and are the opposite of brittle materials.
Strength
The ability of a material to withstand applied loads without failure.
Hardness
The ability of a material to resist scratching, abrasion or indentation. This is measured against Moh’s scale of hardness where 1 is talc, and 10 is diamond.
Elasticity
The ability of a material to return to its original shape and dimensions after being subjected to a load.
Stiffness
The ability of a material to resist elastic deformation under a load. This is measured using Young’s modulus.
Plasticity
The ability of a material to undergo some degree of permanent deformation without rupture.
Malleability
The ability of a material to be hammered or rolled into thin sheets.
Ductility
The ability of a material to be drawn out into thin wire.
Fatigue
The tendency of a material to break when subjected to repeated cyclic loading where the induced stress is well below the plastic limit.
Notch toughness
A measure of the amount of energy needed to induce failure.
