Each

material has a

specific relationship between

stresses in the material (for example, due to

external forces) and the

resulting distortions of

shape and

volume. This relationship is expressed - in idealized form - by

**constitutive equations**. One of the more

well-known examples, named after

Robert Hooke, are the equations that

describe the

mechanical behavior of

solids under the

idealization of

elasticity,

isotropy and

linearity.

*May 3, 2001*