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Mechanical Engineering vocabulary · Mechanics and Materials

Stiffness

Meaning in mechanical engineering, with examples

/ˈstɪfnəs/nounCommon term

In mechanical engineering, stiffness means: How much a part or structure resists bending, stretching or twisting under load. A stiff part deflects only a little; a flexible one deflects a lot.

In Turkish: rijitlik, katılık, direngenlik

How it is used

Used for machine frames, shafts, brackets and in FEA. Stiffness depends on both the material (its modulus of elasticity) and the shape. Engineers add ribs or change the section to increase it. It is given in N/mm or N·m/rad.

Example sentences

  1. Adding two ribs doubled the stiffness of the bracket without adding much weight.

  2. The machine frame needs high stiffness to keep the cutting tool accurate.

Common collocations

  • high stiffness
  • increase stiffness
  • torsional stiffness
  • bending stiffness
  • stiffness-to-weight ratio
  • deflectionHow far a beam, shaft or other part bends or moves away from its original position when a load is applied, usually measured in millimeters.
  • modulus of elasticityA material property that shows how stiff a material is: the ratio of stress to strain in the elastic range. It is about 200 GPa for steel and 70 GPa for aluminum.
  • springAn elastic machine element that stores energy when it is compressed, stretched or twisted and pushes back when released. Most are made of coiled spring steel wire.
  • finite element analysisA computer method that divides a part into many small elements, called a mesh, to calculate stress, deflection, temperature or vibration under given loads.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Mechanics and Materials

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