Adaptivity_set_data
Contents
Data Structure: Adaptivity_set_data |
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Description |
Adaptive set data structure |
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Adaptivity_set_data NUM=ival where ival is the data structure number |
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Overview The Adaptivity_set_data structure is used to define the trigger error and adaptivity data for the complete or parts of the problem. If adaptivity is used then at least one set must be specified corresponding to the complete domain. An arbitrary number of additional sets can be used to specify error and adaptive data for specific regions of the problem. The region to be considered for each set can be specified on a group basis and/or a spatial extent using a variety of different geometry shapes; e.g. rectangle, circle, sphere, cylinder.
Notes •At least one Adaptivity_set_data structure must be specified if adaptivity is used.
Examples demonstrating the usage of Adaptivity_set_data include: •adr_*.dat |
 | Groups List of group numbers in adaptivity set |
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List of group numbers in adaptivity set. If Groups or Group_names (preferred keyword) is not specified then the adaptive set is applied to all the groups in the problem.
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| Group_names List of group names in adaptivity set |
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List of group names in the adaptivity set. If Groups or Group_names (preferred keyword) is not specified then the adaptive set is applied to all the groups in the problem.
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| Remesh_trigger_types Remesh trigger mechanisms |
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List of mechanisms to be used to trigger a remeshing operation. Currently valid options are: • 1 - Area distortion (Default)
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| Distortion_area_data Distortion area data |
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Allowable distortion change, specified as a percentage change, for the area distortion remeshing trigger (i.e. if the area distortion exceeds the specified value a remesh will be triggered at the next error check). •Location 1 - "Area distortion" - Area distortion (Default)
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| Rate_error_type Error based on rate of change of an element variable |
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The size of the mesh upon a remesh operation can be defined as a function of the normalized rate of change of a given variable. The Rate_error_type data structure is used to define the name of the variable to be used in computation of an "error measure" based on the rate of change. The average rate of change of the variable since the last remesh check is computed and then normalised. This gives a normalised spatial distribution of the rate throughout the domain. The element density to be associated with rate distribution is specified using the Rate_error_data keyword. Valid types are dependent on the material model type and comprise: • Plastic materials - any plastic state variable; e.g. 'P_strn' plastic strain • Viscoplastic materials - any viscoplastic state variable; e.g. 'V_strn' viscoplastic strain
Notes •When Rate_error_type is specified then Rate_error_data must also be specified to define the target element size associated with the rate magnitude.
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| Rate_error_data Variable error data |
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A table of data defining the target element size associated with values of the magnitude of the rate error variable (specified using Rate_error_type). The data is provided as a two row table where: •Row 1 - List of error values magnitudes (normalised) in ascending order •Row 2 - Target element size for each error value
Notes •The target element size is computed with the value of the error variable normalised by: Min(Maximum error, 5 x Average error). •The second condition is used to prevent normalisation with anomalous high values. •The error magnitude in the table is therefore defined using values in the range 0.0 - 1.0. •The normalising value is generally set automatically. It can, however, be defined using the Rate_error_reference keyword.
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| Rate_error_reference Variable error reference data |
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The reference value for normalisation of the variable error values before evaluation of the target element size using the data table specified via the Rate_error_data keyword.
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| Region_type Region type (Optional) |
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The remeshing data may be applied only to a target geometric region of the domain. Region_type is used to define the type of adaptive mesh region. Valid types are:
2-D • "All" - Apply to all elements in groups associated with the adaptivity set • "Rectangular" - Rectangular region in 2D • "Circular" - Circular region in 2D
3-D • "All" - Apply to all elements in groups associated with the adaptivity set • "Rectangular" - Hexahedral region in 3D • "Circular" - Spherical region in 3D • "Cylinder" - Cylindrical region in 3D
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| Region_size Size data for mesh region (Optional) |
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Data defining the size for mesh region. The data required is dependent on the region type and the problem dimension; i.e.
2-D "Rectangular region" • Location 1 - Xmin • Location 2 - Ymin • Location 3 - Xmax • Location 4 - Ymax
3-D "Rectangular" (hexahedral) region • Location 1 - Xmin • Location 2 - Ymin • Location 3 - Zmin • Location 4 - Xmax • Location 5 - Ymax • Location 6 - Zmax
2-D "Circular" region • Location 1 - Xcent • Location 2 - Ycent • Location 3 - Radius
3-D "Circular" (spherical) region • Location 1 - Xcent • Location 2 - Ycent • Location 3 - Zcent • Location 4 - Radius
3-D "Cylinder" (cylindrical) region • Location 1 - Xcent1 • Location 2 - Ycent1 • Location 3 - Zcent1 • Location 4 - Radius1 • Location 5 - Xcent2 • Location 6 - Ycent2 • Location 7 - Zcent2 • Location 8 - Radius2
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| Time_curve Load curve number (Optional) |
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Time curve number to be used in defining the movement of the mesh region. This is only used if the the mesh region has geometry bounds and Prescribed_displacement is specified.
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| Remesh_type Remeshing algorithm type (Optional) |
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Remeshing algorithm type to be used for this adaptive set. Valid types are: • "None" - Only compute error data. • "Global" - Remesh all elements in adaptivity set. • "Local" - Only remesh elements that exceed the target error. • "Altern" - Local remesh combined with global mesh generation.
Notes •The default remeshing type is the type specified in the Adaptivity_control_data structure.
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| Deposition_flag Flag denoting use of region with newly deposited groups (Optional) |
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Flag denoting that this adaptivity region is to be used with newly deposited groups (stratigraphy layers). Valid values are: • 0 - Adaptivity set is not used with newly deposited groups (Default). • 1 - Adaptivity set is used with newly deposited groups.
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| Element_sizes Element size bounds for remesh operation (Compulsory) |
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The element size bounds for adaptive remeshing are specified as: •Location 1 - Maximum element size •Location 2 - Minimum element size
Notes •The values for the minimum and maximum element sizes specified in the Adaptivity_set_data structure overwrite the ones specified in the Adaptivity_control_data structure.
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| Updated_region_size Updated size data for mesh region (Optional) |
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The size of the mesh region might be defined to change over a time period defined with a Time_curve. The Updated_region_size data structure is used to define the data corresponding to the updated size for mesh region size. The actual region size, and therefore reference location, is interpolated using the Region_size, Updated_region_size and the time curve ( Time_curve ). The data required is dependent on the region type and the problem dimension; i.e.
2-D "Rectangular region" • Location 1 - Xmin • Location 2 - Ymin • Location 3 - Xmax • Location 4 - Ymax
3-D "Rectangular" (hexahedral) region • Location 1 - Xmin • Location 2 - Ymin • Location 3 - Zmin • Location 4 - Xmax • Location 5 - Ymax • Location 6 - Zmax
2-D "Circular" region • Location 1 - Xcent • Location 2 - Ycent • Location 3 - Radius
3-D "Circular" (spherical) region • Location 1 - Xcent • Location 2 - Ycent • Location 2 - Zcent • Location 3 - Radius
3-D "Cylinder" (cylindrical) region • Location 1 - Xcent1 • Location 2 - Ycent1 • Location 3 - Zcent1 • Location 4 - Radius1 • Location 5 - Xcent2 • Location 6 - Ycent2 • Location 7 - Zcent2 • Location 8 - Radius2
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| Local_remesh_distortion_data Local remeshing data (Only if local remeshing is active) |
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The elements to be remeshed in a local remeshing operation are defined as the elements where the area distortion error is greater than the value specified using Local_remesh_distortion_data. A single value is specified which should be in the range 0.0 < Local_remesh_distortion_data < Distortion_area_data, where Distortion_area_data is the allowable distortion before triggering a remesh operation. Typically: •Distortion_area_data = 20 (20% allowable change in element area), and •Local_remesh_distortion_data = 10 (remesh all elements with distortion > 10%)
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| Local_remesh_density_fact Local remesh error data (Only if local remeshing is active) |
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When Local_remesh_density_fact is specified it is used to identify elements to be locally remeshed based on the ratio of the current element size ( lcurr) to the target element size ( ltarg ). Specifically elements will be remeshed if lcurr x floc > ltarg where floc is the value specified using the Local_remesh_density_fact
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| Prescribed_displacement Prescribed displacement for mesh region |
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A prescribed displacement may be applied to a mesh region. The reference values of the prescribed displacement for mesh region are specified as:
2-D Model • location 1 - Xdisp • location 2 - Ydisp
3-D Model • location 1 - Xdisp • location 2 - Ydisp • location 3 - Zdisp
Notes •The displacement rate will be controlled by the assigned Time_curve .
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| Coarsening_type Variable to be used to limit mesh coarsening |
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The coarsening can be used to define a target maximum element size as a function of a specified material variable (e.g. plastic strain). Then Coarsening_type is used to define the name of the variable to be used to limit the maximum size of elements. Valid types are dependent on the material model type and comprise: • Plastic materials - any plastic state variable; e.g. 'P_strn' plastic strain • Viscoplastic materials - any viscoplastic state variable; e.g. 'V_strn' viscoplastic strain
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| Coarsening_data Plastic strain coarsening data |
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Coarsening_data is used to define the target maximum element size as a function of the value of the variable defined in Coarsening_type (e.g. plastic strain). It may therefore be used to prevent over-coarsening of the mesh in regions where significant plastic strain has occurred (e.g. strain localizations). The data is provided in two rows as: •Row 1 - Coarsening type variable (e.g. Plastic strain) in ascending order •Row 2 - Target maximum element size
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| Spatial_grid Name of the spatial grid to be used to assign the element size |
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Name of the spatial grid to be used to assign the element size. This functionality allows definiton of the maximum and minumum element sizes using a point cloud ('Cloud') spatial grid. The grid nodal variables are defined as:' •'SSIZMX' - Maximum element size •'SSIZMN' - Minimum element size
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