Stress-Strain Relation
The stress-strain relation for the axial deformation in the beam is described by
where
E
is Young’s modulus, and
σ
i
is the initial stress.
The stress strain relation for the torsional and shear deformation is
where
τ
is the shear stress,
γ
is the shear strain and
G
is the shear modulus. Often the material data is given in terms of Young’s modulus and Poisson’s ratio
ν
, in which case
G
is defined as
