[CIG-SHORT] "Runtimeerror Infeasible stress state" - cannot project back to yield surface.

[Ma, Xiao]

Hi,
I am running a simulation using Druckerprager elstoplastic model, when I run the code, I get the following error
"Runtimeerror Infeasible stress state" - cannot project back to yield surface.
Here is how I wrote the plastic material part :


[pylithapp.timedependent]

materials = [plastic]

[pylithapp.timedependent.materials]



elastic = pylith.materials.DruckerPragerPlaneStrain


[pylithapp.timedependent.materials.plastic]


# Label for material

label = Plastic material


# Nodeset id from CUBIT

id = 1


# Spatial database with physical properties for elastic material

db_properties.label =Plastic properties

db_properties.iohandler.filename = matprops.spatialdb


# Set the basis functions and quadrature:

# 2-D Lagrange cell with 2nd order quadrature

quadrature.cell = pylith.feassemble.FIATLagrange

quadrature.cell.dimension = 2

quadrature.cell.quad_order = 2

************************************

And This is the material database I am using .

#SPATIAL.ascii 1

SimpleDB {

// number of physical properties

num-values = 6


// Names and units of physical properties

value-names = density vs vp friction-angle cohesion dilatation-angle // names of the material property values

value-units = kg/m**3 m/s m/s degree kPa degree // units


// Number of locations where physical properties are given

// 1 location -> data is uniform -> data dimension is 0

num-locs = 1

data-dim = 0


// Problem is in 2-D

space-dim = 2


// Coordinate system (2-D with coordinates in meters)

cs-data = cartesian {

to-meters = 1.0

space-dim = 2

}

}

// Columns are x, y, density, vs, vp

0.0 0.0 2500.0 3000.0 5291.502622129181 30.0 50.0 30.0


Best,

XIao


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