Case 2 Refinement using Mesh Coarsening Criteria

 

Coarsening data may be defined in the Adaptivity_set_data data structure to limit the size of elements based on the value of a state variable; e.g. the plastic strain.  This is achieved by specifying a table of data where:

•Row 1: defines the value of the state variable in ascending order.

•Row 2: defines the maximum allowable element size corresponding to the state variable value.

 

Data File

 

 

* Adaptivity_set_data  NUM=1

! ---------------------------------

 Distortion_area_data IDM=1

   15

 Element_sizes IDM=2

  /Max. Element Size/         1.5

  /Min. Element Size/        0.75

 Coarsening_type          "P_strn"

 Coarsening_data IDM=3 JDM=2

  /Plastic Strain/   0.0   0.20   0.50

  /Element Size/    1.50   1.00   0.75

 

 

The minimum element size is reduced from the original 1.5 to 0.75

The coarsening type is defined on "P_strn" - plastic strain.  The state variable names for each material model are defined in the Material_data section of the reference manual.

The maximum element size is defined by the table

Plastic Strain

Maximum Element Size

0.0

1.5

0.2

1.0

0.5

0.75

 

The result files for the project are in directory: mech_004\exercises\Case 2\results.  The contour plots for plastic strain show the influence of the mesh coarsening data, with a finer mesh in the region of high plastic strain.  This provides more kinematic freedom resulting in a more localised deformation on the shear band relative to Case 1.

 

mech_004_case2_01mech_004_case2_05

Configuration at Time t=0.5s

mech_004_case2_02mech_004_case2_04

Configuration at Time t=1.0s