burgers

bulk f

elastic bulk modulus, K

shear-kelvin f

Kelvin shear modulus, GK

shear-maxwell f

Maxwell shear modulus, GM

viscosity-kelvin f

Kelvin viscosity, nK

viscosity-maxwell f

Maxwell viscosity, nM

strain-kelvin-xx f

Kelvin strain, eKxx

strain-kelvin-yy f

Kelvin strain, eKyy

strain-kelvin-zz f

Kelvin strain, eKzz

strain-kelvin-xy f

Kelvin strain, eKxy

strain-kelvin-xz f

Kelvin strain, eKxz

strain-kelvin-yz f

Kelvin strain, eKyz

Notes:

• Only one of the two options is required to define the elasticity: bulk modulus K and shear modulus G, or Young’s modulus E and Poisson’s ratio v.
• The creep behavior is triggered by deviatoric stress, while the volumetric behavior does not consider creep.
• If the stresses are changed in a FLAC3D model with the zone initialize command, the internal Kelvin strains, eKij, will not be compatible with them, and movement will occur until the strains adjust. To avoid this incompatibility, the internal strains may be set to reflect the current values of stresses. The internal Kelvin strains, eKij, are available for user inspection and modification. An example FISH function is SetKStrain.f3fis. This function should be invoked immediately following initialization of stresses.