Also known as unit deformation, strain is the ratio of the change in length caused by the applied force, to the original length
Strain
ε = δ/L, where δ is the deformation and L is the original length
Yield Point
The point at which the material will have an appreciable elongation or yielding without any increase in load
Ultimate Strength
The maximum ordinate in the stress-strain diagram, also known as tensile strength
Rupture Strength
The strength of the material at rupture, also known as breaking strength
Modulus of Resilience
The work done on a unit volume of material as the force is gradually increased from O to PL, in Nm/m^3
Creep is the slow and continuous deformation of a material under a constant stress, usually at high temperatures
Fatigue is the progressive and localized damage of a material under cyclic or fluctuating stress, usually at low or moderate temperatures
Hooke's Law
The law of elasticity discovered by the English scientist Robert Hooke in 1660, which states that, for relatively small deformations of an object, the displacement or size of the deformation is directly proportional to the deforming force or load
Elastic Limit
The limit beyond which the material will no longer go back to its original shape when the load is removed, or it is the maximum stress that may developed such that there is no permanent or residual deformation when the load is entirely removed
Hooke's Law
σ = Eε
Under Hooke's Law conditions, the object returns to its original shape and size upon removal of the load
