For isotropic materials it is related to Young modulus (E) and Poisson's ratio (ν) as:

G_T = \frac{E}{3 \, (2 + \nu)}

See also

Physics / Mechanics / Continuum mechanics / Continuum Body / Deformation

[ Solid Mechanics ] [ Fluid Mechanics]

[Compressibility] [ Young modulus (E) ][ Poisson's ratio (ν) ][ Bulk modulus ]