Materials#

Material properties are set with femorph_solver.Model.mp(), the direct analogue of MAPDL’s MP command. Every property is a scalar attached to a material id; an element references its material by stamping a MAT id with mat() before e() creates it.

MP#

m = femorph_solver.Model()
m.mp("EX", 1, 2.1e11)       # Young's modulus (Pa)
m.mp("PRXY", 1, 0.30)       # Poisson ratio
m.mp("DENS", 1, 7850.0)     # density (kg/m^3)

The first argument is the property name, the second is the material id, the third is the scalar value. Units are whatever’s consistent across EX, the element geometry, and any forces — femorph-solver does not track units.

Supported properties#

The femorph_solver.MaterialProperty enum enumerates every property name femorph-solver’s element kernels currently look up. Accepting the enum member or the raw string is equivalent:

Token

Meaning

Used by

EX

Young’s modulus

All solids, beams, shells, plane, truss.

PRXY

Poisson’s ratio (isotropic)

All solids, beams, shells, plane.

DENS

Mass density

Every element that contributes to \(M\).

GXY

Transverse shear modulus

Reserved for future shell / beam transverse-shear paths.

ALPX

Thermal expansion coefficient

Reserved for future thermal-strain coupling.

 
from femorph_solver import MaterialProperty as MP

m.mp(MP.EX, 1, 2.1e11)      # enum-typed — identical to "EX"

Multiple materials#

Assign different materials to different element groups by alternating the mat() stamp:

m.mat(1)                         # MAT,1
m.e(1, 2, 3, 4, 5, 6, 7, 8)      # uses material 1

m.mat(2)                         # MAT,2
m.e(9, 10, 11, 12, 13, 14, 15, 16)   # uses material 2

m.mp("EX", 1, 2.1e11)            # material 1: steel-ish
m.mp("PRXY", 1, 0.30)
m.mp("DENS", 1, 7850.0)

m.mp("EX", 2, 7.0e10)            # material 2: aluminium-ish
m.mp("PRXY", 2, 0.33)
m.mp("DENS", 2, 2700.0)

When a CDB is loaded, each element arrives with a material id already stamped; there’s no additional registration step beyond calling mp() for every mat_id that appears on the grid.

Introspection#

The current material table is available as Model.materials:

m.materials
# {1: {'EX': 2.1e11, 'PRXY': 0.3, 'DENS': 7850.0},
#  2: {'EX': 7.0e10, 'PRXY': 0.33, 'DENS': 2700.0}}

Element kernels read the matching dict directly, so any additional scalar you stash under a known property name is visible to them — this is the extension path for per-element-class switches (e.g. _SOLID185_FORMULATION; see the SOLID185 reference).

Limitations (today)#

  • Linear isotropic only. Orthotropic / anisotropic tensors, rate dependence, plasticity, temperature-dependent curves are not yet implemented.

  • Scalar per id. Tensor-valued DMATRIX / ANEL MAPDL blocks aren’t round-tripped yet; they’re parsed on CDB load but ignored during assembly.

See also#