Linear Elasticity: Material JSON Keys

Linear elasticity requires the scenario json object to have "type": "LinearElasticity".

Materials

Linear Elasticity and Modal scenarios both use our structural material types. All materials need a density value, and can optionally include a "units": member. Note that all materials will be specified in MKS unless units are specified.

Isotropic

For isotropic materials, the user must specify a failure criterion type. This is used during sampling to calculate the topological sensitivity and danger level, fields which aren’t sampled for other structural material types. The choices for failure criterion type are:

"Unspecified" // Do not calculate the danger level
"VonMises"
"MaximumShearStress"
"Rankine"
"CoulombMohr"
"ModifiedMohr"

An example of how this would look in json:

{
  "compressive_strength": 690000000.0,
  "density": 7200.0,
  "failure_criterion": "CoulombMohr",
  "poisson_ratio": 0.27,
  "tensile_strength": 170000000.0,
  "yield_strength": 0.0,
  "youngs_modulus": 100000000000.0
}

Orthotropic

Orthotropic materials have material properties that vary depending on the orientation. The elastic modulus in the x, y and z directions are defined by Ex, Ey and Ez, the Poisson’s ratio by vxy, vxz and vyz, and the shear modulus by Gxy, Gxz and Gyz. The material properties can be transformed by specifying a transform matrix, for example, to simulate composite fibers that are rotated by 45° relative to the x-axis. The type must be Orthotropic.

An example configuration for a composite material of Kevlar and epoxy, with the fibers rotated by 45° relative to the x-axis, is shown below.

{
  "Ex": 85000000000.0,
  "Ey": 5600000000.0,
  "Ez": 5600000000.0,
  "Gxy": 2100000000.0,
  "Gxz": 2100000000.0,
  "Gyz": 2280000000.0,
  "density": 1350,
  "transform":
    [0, 0.7071, 0.7071,
     0, -0.7071, 0.7071,
     1, 0, 0],
  "vxy": 0.34,
  "vxz": 0.23,
  "vyz": 0.34,
  "type": "Orthotropic"
}