Viscoelastic relaxation of stresses resulting from an imposed simple shear strain. No body forces are imposed.
Benchmark #3a: Solve using a Maxwell viscoelastic material rheology
Benchmark #3b: Solve using a Burger's body rheological description
Benchmark #3c: Solve using a power-law material description
- Test relevant constitutive relations
- Verify timing of output in specific codes (i.e., is output written at the beginning or end of the step).
- Model size: 24 km by 24 km by 24 km (0 km ≤ x; y ≤ 24 km; -24 km ≤ z ≤ 0 km)
- Elastic material properties: Poisson solid, G = 30 GPa
- Maxwell viscoelastic material properties: η = 1018 Pa-s
- Burger's body material properties: Maxwell element as above, Kelvin-Voigt element has GKV = 10 GPa, ηM = 1017 Pa-s
- Power-law material properties: ηref = 1018 Pa-s and σref = 105 Pa. (Note: This value is chosen because the maximum initial elastic stress is of order 106 Pa; although all of that is deviatoric, the deviatoric stress decreases with time.)
- Density and Gravity: None
- Boundary conditions: Bottom pinned
Sides pinned in y and z; free in x
Top pinned in y and z; 1 m of displacement imposed in x
- Coarse mesh node spacing: dx = dy = dz = 2 km
Requested Output and Results
Mesh Variations: As memory, time, and patience allow, run models at 1/2, 1/4, and 1/8, etc. the original coarse mesh spacing, investigate variable mesh spacing, and/or employ a variety of element types.
For All Benchmark Variations:
- Stresses along a path through (0,0,-24) and (24,24,0) at t = 0, 1, 5, and 10 years.
- Displacements along a path through (0,0,-24) and (24,24,0) at t = 0, 1, 5, and 10 years.
- CPU time, wallclock time, memory usage info, compiler info, and platform info
Analytical solutions for each material rheology will be posted at geoweb.mit.edu/fe.