Error in simulating biphasic uniaxial tensile test

[WuYan936968204]

When I simulate biphasic uniaxial tensile experiments, I get this error.

There was also an error when changing "N_constituents: 1" to "N_constituents: 2", but it was different from the previous one.

In order to understand the cause of the error, I only set two grains, but it couldn't be solved, so I asked for help online.

[eisenlohr]

The second error results from a mismatch between the number of constituents specified per material ID, here 2 with volume fraction 0.8 and 0.2, and the value of the N_constituents parameter in the selected homogenization scheme, here bicrystal and N_consituents: 1. The homogenization bicrystal used in the material definitions expects only one constituent because you specified

homogenization:
  bicrystal:
    N_constituents: 1

but you provide two entries (with volume fractions 0.8 and 0.2) in the constituents list for each material ID.

You need to change the entry to homogenization: bicrystal: N_constituents: 2

The first error states that the homogenization scheme pass can only be used for a single-constituent situation, i.e., exclusively with N_constituents: 1. Your situation involves an actual homogenization problem, i.e., how is the deformation of the (composite) material point partitioned over the two constituents, and how is their respective stress combined to give a single material point stress? Therefore, you cannot use type: pass but must select another scheme. My suggestion for a start would be to use isostrain, which assumes that the deformation of each constituent is the same as that of the material point, and the resulting stress at the material point is the volume-weighted average of the individual constituent stress.

homogenization:
  bicrystal:
    N_constituents: 2
    type: isostrain

Please also see the configuration examples provided in the folder examples/config/homogenization.

[WuYan936968204]

With your assistance, the issue was resolved successfully. Please accept my sincere gratitude.