Name

Type

Description

Default

modal_solution_methods (alpha)

LIST

Defines the type of modal solution method to compute. Currently only a frequency extraction method is supported.

outputs (alpha) [optional]

LIST

The outputs object holds all output objects, identified by user defined identifiers. An output object defines an output for this procedure. Remark: If a chosen set was specified as an immersed set during geometry creation, that set must the only item in the sets list. If an immersed set is selected the output command will produce two separate files. The main file will include a tessellated surface representation of the boundary. The second file (with suffix envelope), will include a smooth volumetric output of the U-spline envelope domain for the immersed set. When viewing results on the envelope domain take care that only values on the interior of the model of interest are considered as values at the extremities of this representation may not exhibit physically relevant behavior. Not all elements from the original mesh used may be shown, in general only those that intersect the model of interest will be included.

boundary_conditions (alpha) [optional]

LIST

interactions (alpha) [optional]

LIST

Each object in the interaction definitions array defines an interaction for the procedure. Currently the supported interactions are mechanical_contact and tied_constraint.

interaction_search_parameters (alpha) [optional]

LIST

Each object in the interaction search definitions array defines search parameters to be used in an interaction. Currently the supported search definitions is a sensor-based layout.

Name

Type

Description

Default

label (alpha)

STRING

The user defined identifier for this modal solution method definition.

frequency_extraction (alpha)

SUB OBJECT

See linked documentation

Name

Type

Description

Default

minimum_frequency (alpha)

DOUBLE

Minimum frequency in the frequency domain of interest.

maximum_frequency (alpha)

DOUBLE

Maximum frequency in the frequency domain of interest.

Name

Type

Description

Default

label (alpha)

STRING

The user defined identifier for this output definition.

tessellate [optional] (alpha)

true|false

The output should be tessellated to hdf5 files for consumption by third party tools.

field (alpha) | history (alpha)

SUB OBJECT | SUB OBJECT

The definition of the class of output

Name

Type

Description

Default

database_name (alpha)

STRING

The file name prefix of the output file that will be written to disk. The field output is written out in the ParaView *.pvd format.

interval (alpha)

STRING

The user defined identifier of the interval to use for this output. This interval will specify when the output should be written, as determined by the time_increment or step_increment values within the interval. A time_increment of 0 acts the same as a step_increment of either 0 or 1, writing output after each intermediate solution step. A negative value for time_increment or step_increment will output only at the bounds of the interval.

part | set

STRING | STRING

Defines the set or part to be operated on. If nothing is specified, it is equivalent to including every part.

variables (release)

SUB OBJECT

See linked documentation

element_variable_output_strategy [optional] (alpha)

“max” | “min” | “average” | “interpolate”

This specifies how values are calculated within each cell. min, max, and average take the minimum, maximum, or average component point values at the integration points and report them across the entire cell. interpolate interpolates the component values from the integration points.

include_integration_point_output [optional] (alpha)

true|false

Whether to include output at integration points. Output at integration points is not included by default.

false

Name

Type

Description

Default

part

STRING

The user defined label of the part that defines the set.

set

STRING

The user defined identifier of the geometric set.

Name

Type

Description

Default

displacement | velocity (beta) | acceleration (beta) | stress | nominal_strain (beta) | plastic_strain (beta) | deformation_gradient (alpha) | failure_indicator (alpha)

[ “all” | “x” | “y” | “z” | “magnitude”, ... ] | [ “all” | “x” | “y” | “z” | “magnitude”, ... ] | [ “all” | “x” | “y” | “z” | “magnitude”, ... ] | [ “all” | “xx” | “yy” | “zz” | “xy” | “yz” | “xz” | “von_mises” | “tresca” | “pressure” | “triaxiality” | “octahedral” | “total_measure” | “min_principal” | “mid_principal” | “max_principal” | “invariant_I1” | “invariant_I2” | “invariant_I3” | “invariant_J2” | “invariant_J3”, ... ] | [ “all” | “xx” | “yy” | “zz” | “xy” | “yz” | “xz”, ... ] | [ “equivalent”, ... ] | [ “all” | “xx” | “xy” | “xz” | “yx” | “yy” | “yz” | “zx” | “zy” | “zz” | “determinant”, ... ] | [ “value”, ... ]

Any of the given options can be defined

Name

Type

Description

Default

displacement

[ “all” | “x” | “y” | “z” | “magnitude”, ... ]

velocity (beta)

[ “all” | “x” | “y” | “z” | “magnitude”, ... ]

acceleration (beta)

[ “all” | “x” | “y” | “z” | “magnitude”, ... ]

stress

[ “all” | “xx” | “yy” | “zz” | “xy” | “yz” | “xz” | “von_mises” | “tresca” | “pressure” | “triaxiality” | “octahedral” | “total_measure” | “min_principal” | “mid_principal” | “max_principal” | “invariant_I1” | “invariant_I2” | “invariant_I3” | “invariant_J2” | “invariant_J3”, ... ]

nominal_strain (beta)

[ “all” | “xx” | “yy” | “zz” | “xy” | “yz” | “xz”, ... ]

plastic_strain (beta)

[ “equivalent”, ... ]

deformation_gradient (alpha)

[ “all” | “xx” | “xy” | “xz” | “yx” | “yy” | “yz” | “zx” | “zy” | “zz” | “determinant”, ... ]

failure_indicator (alpha)

[ “value”, ... ]

Name

Type

Description

Default

interval (alpha)

STRING

The user defined identifier of the interval to use for this output.

Name

Type

Description

Default

label (alpha)

STRING

A user defined identifier for this boundary condition.

components (alpha)

[ “x” | “y” | “z”, ... ]

Specifies which displacement components to constrain.

part | set

STRING | STRING

Defines the set or part to be operated on

penalty (alpha) [optional]

SUB OBJECT

See linked documentation

quadrature_options (beta) [optional]

SUB OBJECT

See linked documentation

Name

Type

Description

Default

part

STRING

The user defined label of the part that defines the set.

set

STRING

The user defined identifier of the geometric set.

Name

Type

Description

Default

value (alpha)

DOUBLE

The value of the penalty parameter, in the range $[0,\infty)$, determining how strongly the constraint is enforced. The precise interpretation of this value depends on the choice of the parameter dimensionless, whose documentation provides a more detailed discussion. Note that the default value assumes that dimensionless is also set to its default value of true.

1e1

dimensionless (alpha)

true|false

If this parameter is true, then the penalty value is interpreted as the dimensionless constant $C$ in the formula $\beta = CEh^{c-2}$, where $E$ is a scalar estimate of the material stiffness (i.e., the Young's modulus in elasticity or the thermal conductivity in heat conduction), $h$ is a measure of element size (with units of length), and $c$ is the co-dimension of the constrained set, i.e., 0 for volumes, 1 for surfaces, 2 for curves, or 3 for points. If this parameter is false, then the penalty value is instead interpreted as the dimensional value of $\beta$ directly. The dimensionless option is recommended for most use cases. To interpret the dimensionless penalty value for the common case of constrained boundaries and interfaces ($c=1$) in elasticity, it is roughly the ratio of a single element's change in length under a given tensile load to the error allowed in the consraint. Note that, for any positive value, the constraint error will go to zero as the mesh is refined, since the specimen's overall change in length is distributed over more elements. Selecting too large of a penalty value makes the discrete problem harder to solve. The default value represents a good balance between accuracy and efficiency for most practical applications, but higher values may be appropriate for certain situations, such as calibrating material models with single-element patch tests.

true

Name

Type

Description

Default

quadrature [optional] (beta)

“QP1” | “QP0” | “Q1” | “Q2” | “Q3” | “Q4” | “Q5” | “Q6” | “Q7” | “Q8” | “Q9” | “Q10”

Quadrature type enumeration. The quadrature type determines the point layout over a patch or patch element. The schemes following the pattern “Q#” specify that a Gauss quadrature scheme with #-points will be used. The schemes following the pattern “QP#” specify that a Gauss quadrature scheme with $(P+\#)$-points will be used, where $P$ is the degree of the patch's or patch element's basis.

QP1

optimized_cut_quadrature_strategy [optional] (beta)

“match_uncut” | “reduce_from_uncut” | “match_basis”

Strategy to choose the degree of accuracy for quadrature on cut cells. The default strategy of reduce_from_uncut chooses quadrature rules with similar numbers of points as those used on uncut cells, as specified by quadrature; it has lower formal accuracy (integrating tensor products of monomials up to degree $N-1$ for uncut quadrature Q$N$), but is a good default choice for practical calculations. The strategy match_uncut matches the formal accuracy of the quadrature on uncut cells, but is significantly more costly. The strategy match_basis chooses a rule that exactly integrates the basis functions; this is equivalent to reduce_from_uncut if the uncut cells use the default quadrature of QP1, but may differ for other choices of uncut quadrature.

reduce_from_uncut

optimized_cut_quadrature_degree [optional] (beta)

NONNEGATIVE INTEGER

If provided, this value overrides optimized_cut_quadrature_strategy by specifying an explicit polynomial degree of accuracy for optimized quadrature rules on cut cells.

optimization_method [optional] (beta)

“tet_pruning” | “grid_doubling” | “linear_programming”

Specifies the preferred method of quadrature generation for cut cells. If the preferred method fails on a particular cell, the other methods will be used in an attempt to recover.

tet_pruning

optimization_residual_tolerance [optional] (beta)

DOUBLE

The absolute residual tolerance used in quadrature optimization on cut cells. A smaller value will result in a more accurate quadrature rule, but may increase the time to compute quadrature rules for cut cells.

1e-12

optimization_lawson_hanson_solve_completion [optional]

true|false

An experimental option that controls the convergence behavior of quadrature optimization. For best results it is recommended to set this value to true. If set to true this causes each iteration of quadrature optimization to solve to the highest accuracy possible. The results at each iteration are then checked against the optimization_residual_tolerance to determine if a sufficient rule has been found. If this value is set to false then the optimization_residual_tolerance is passed to the solve at each iteration and can cause the solve step to terminate more quickly which can result in faster execution and a lower number of quadrature points. However the quality and accuracy of the resulting rule may be suspect.

true

Name

Type

Description

Default

label (alpha)

STRING

User defined identifier for this interaction definition.

quadrature_options (beta) [optional]

SUB OBJECT

See linked documentation

tied_constraint (alpha) | material_interface (alpha)

SUB OBJECT | SUB OBJECT

Name

Type

Description

Default

quadrature [optional] (beta)

“QP1” | “QP0” | “Q1” | “Q2” | “Q3” | “Q4” | “Q5” | “Q6” | “Q7” | “Q8” | “Q9” | “Q10”

Quadrature type enumeration. The quadrature type determines the point layout over a patch or patch element. The schemes following the pattern “Q#” specify that a Gauss quadrature scheme with #-points will be used. The schemes following the pattern “QP#” specify that a Gauss quadrature scheme with $(P+\#)$-points will be used, where $P$ is the degree of the patch's or patch element's basis.

QP1

optimized_cut_quadrature_strategy [optional] (beta)

“match_uncut” | “reduce_from_uncut” | “match_basis”

Strategy to choose the degree of accuracy for quadrature on cut cells. The default strategy of reduce_from_uncut chooses quadrature rules with similar numbers of points as those used on uncut cells, as specified by quadrature; it has lower formal accuracy (integrating tensor products of monomials up to degree $N-1$ for uncut quadrature Q$N$), but is a good default choice for practical calculations. The strategy match_uncut matches the formal accuracy of the quadrature on uncut cells, but is significantly more costly. The strategy match_basis chooses a rule that exactly integrates the basis functions; this is equivalent to reduce_from_uncut if the uncut cells use the default quadrature of QP1, but may differ for other choices of uncut quadrature.

reduce_from_uncut

optimized_cut_quadrature_degree [optional] (beta)

NONNEGATIVE INTEGER

If provided, this value overrides optimized_cut_quadrature_strategy by specifying an explicit polynomial degree of accuracy for optimized quadrature rules on cut cells.

optimization_method [optional] (beta)

“tet_pruning” | “grid_doubling” | “linear_programming”

Specifies the preferred method of quadrature generation for cut cells. If the preferred method fails on a particular cell, the other methods will be used in an attempt to recover.

tet_pruning

optimization_residual_tolerance [optional] (beta)

DOUBLE

The absolute residual tolerance used in quadrature optimization on cut cells. A smaller value will result in a more accurate quadrature rule, but may increase the time to compute quadrature rules for cut cells.

1e-12

optimization_lawson_hanson_solve_completion [optional]

true|false

An experimental option that controls the convergence behavior of quadrature optimization. For best results it is recommended to set this value to true. If set to true this causes each iteration of quadrature optimization to solve to the highest accuracy possible. The results at each iteration are then checked against the optimization_residual_tolerance to determine if a sufficient rule has been found. If this value is set to false then the optimization_residual_tolerance is passed to the solve at each iteration and can cause the solve step to terminate more quickly which can result in faster execution and a lower number of quadrature points. However the quality and accuracy of the resulting rule may be suspect.

true

Name

Type

Description

Default

target_set (alpha)

STRING

Specifies the target interaction surface.

source_set (alpha)

STRING

Specifies the source interaction surface.

region_search_method (alpha)

STRING

Specifies the object in interaction-search-parameters to define the constraint search method.

penalty (alpha) [optional]

SUB OBJECT

See linked documentation

offset [optional] (alpha)

true|false

A tied constraint property that, if true, will use a formulation that approximately maintains the initial gap distance. If false, the tied constraint formulation will not maintain gap distances under rotation, but is less expensive to compute.

true

Name

Type

Description

Default

value (alpha)

DOUBLE

The value of the penalty parameter, in the range $[0,\infty)$, determining how strongly the constraint is enforced. The precise interpretation of this value depends on the choice of the parameter dimensionless, whose documentation provides a more detailed discussion. Note that the default value assumes that dimensionless is also set to its default value of true.

1e1

dimensionless (alpha)

true|false

If this parameter is true, then the penalty value is interpreted as the dimensionless constant $C$ in the formula $\beta = CEh^{c-2}$, where $E$ is a scalar estimate of the material stiffness (i.e., the Young's modulus in elasticity or the thermal conductivity in heat conduction), $h$ is a measure of element size (with units of length), and $c$ is the co-dimension of the constrained set, i.e., 0 for volumes, 1 for surfaces, 2 for curves, or 3 for points. If this parameter is false, then the penalty value is instead interpreted as the dimensional value of $\beta$ directly. The dimensionless option is recommended for most use cases. To interpret the dimensionless penalty value for the common case of constrained boundaries and interfaces ($c=1$) in elasticity, it is roughly the ratio of a single element's change in length under a given tensile load to the error allowed in the consraint. Note that, for any positive value, the constraint error will go to zero as the mesh is refined, since the specimen's overall change in length is distributed over more elements. Selecting too large of a penalty value makes the discrete problem harder to solve. The default value represents a good balance between accuracy and efficiency for most practical applications, but higher values may be appropriate for certain situations, such as calibrating material models with single-element patch tests.

true

Name

Type

Description

Default

interface (alpha)

STRING

The label of the interaction in the geometry/interactions array.

penalty (alpha) [optional]

SUB OBJECT

See linked documentation

region_search_method [optional] (alpha)

STRING

The search paramaters to use.

offset [optional] (alpha)

true|false

A material interface property that, if true, will use a formulation that approximately maintains any initial gap due to a small geometric mismatch at the material interface. If false, the tied constraint formulation may be less robust to geometry error, but is less expensive to compute.

true

Name

Type

Description

Default

value (alpha)

DOUBLE

The value of the penalty parameter, in the range $[0,\infty)$, determining how strongly the constraint is enforced. The precise interpretation of this value depends on the choice of the parameter dimensionless, whose documentation provides a more detailed discussion. Note that the default value assumes that dimensionless is also set to its default value of true.

1e1

dimensionless (alpha)

true|false

If this parameter is true, then the penalty value is interpreted as the dimensionless constant $C$ in the formula $\beta = CEh^{c-2}$, where $E$ is a scalar estimate of the material stiffness (i.e., the Young's modulus in elasticity or the thermal conductivity in heat conduction), $h$ is a measure of element size (with units of length), and $c$ is the co-dimension of the constrained set, i.e., 0 for volumes, 1 for surfaces, 2 for curves, or 3 for points. If this parameter is false, then the penalty value is instead interpreted as the dimensional value of $\beta$ directly. The dimensionless option is recommended for most use cases. To interpret the dimensionless penalty value for the common case of constrained boundaries and interfaces ($c=1$) in elasticity, it is roughly the ratio of a single element's change in length under a given tensile load to the error allowed in the consraint. Note that, for any positive value, the constraint error will go to zero as the mesh is refined, since the specimen's overall change in length is distributed over more elements. Selecting too large of a penalty value makes the discrete problem harder to solve. The default value represents a good balance between accuracy and efficiency for most practical applications, but higher values may be appropriate for certain situations, such as calibrating material models with single-element patch tests.

true

Name

Type

Description

Default

label (alpha)

STRING

User defined identifier for this interaction search definition.

sensor_based (alpha)

SUB OBJECT

See linked documentation

Name

Type

Description

Default

max_iterations (alpha)

NONNEGATIVE INTEGER

Specifies the maximum iterations for the search.

10

relative_tolerance (alpha)

DOUBLE

Specifies the relative search tolerance.

1e-8

bounding_box_extension (alpha)

DOUBLE

Specifies the extension of the bounding box for the interaction search.

1e-3