Elastic properties

Hooken laista

Materiaaliopissa laki esitetään yleensä muodossa:

σ = Eε,

jolloin σ on jännitys, E Youngin moduuli ja ε muodonmuutos tai

τ = Gγ,

jossa τ on leikkausjännitys, G liukumoduuli ja γ leikkausmuodonmuutos.

Stress - jännitys σ

• The average amount of force exerted per unit area. It is the internal resistance a material offers to being deformed and is measured in terms of the applied load.

Strain - muodonmuutos ε

• Geometrical measure of deformation representing the relative displacement between particles in a material body

Elastic modulus kimmokerroin.

• The ratio of tensile stress to tensile strain.

Bulk modulus - kokoonpuristumiskerroin -∆P / (∆V/V)

Tensile strenght - vetolujuus

• Yield strength. The stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently.
• Ultimate strength. The maximum stress a material can withstand when subjected to tension, compression or shearing. It is the maximum stress on the stress-strain curve.
• Breaking strength. The stress coordinate on the stress-strain curve at the point of rupture.

Shear stress - leikkausjännitys  τ

Stress which is applied parallel or tangential to a face of a material, as opposed to a normal stress which is applied perpendicularly.

Shear modulus - liukumoduuli G 

• The ratio of shear stress to the shear strain
  

Shear strain  leikkausmuodonmuutos  Γ

• Strain that acts parallel to the surface of a material that it is acting on.

• Viscoelasticity - time dependent mechanical behavior that approaches elastic behavior at long times
• Creep - time dependent strain that accompanies an applied constant stress
• Stress relaxation - time dependent stress that accompanies an applied constant strain
• Hysteresis - energy dissipation during loading and unloading