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Output, field

*Output, field

The output can either be given for the external software packages

  • Paraview: <format 1> = vtk

With the <format 2> keyword you can specify whether the output should be given in ASCII or binary format by using <format 2> = ascii or <format 2> = binary, respectively. Both <format 1> and <format 2> are not needed in case print is used. The following definitions count for both field and print.

Use the *Frequency keyword to set the output frequency <output interval> in increments (integer required). The output will always be written to the output database at the beginning of each step and at the last increment of each step. Use the following sub-keywords to define output fields of variables stored at the nodes and the integration points of the elements:

Node output

*Output, field, <format 1>, <format 2> [, flush]
*Node, nset = <set name>
<variable 1>, ..., <variable n>

This option is used to write node variables to the output database. It must be used as a sub-keyword of the *Output keyword. Set <set name> equal to the node set name for which the output should be defined. In the subsequent line, the output variables are defined.

The following variables are currently available:

  • U:

    Solid displacements. Vector field \(\boldsymbol{u}\), magnitude \(|\boldsymbol{u}|\) and components \(u_i\) for \(i=\{x,y,z\}\).

  • V:

    Solid velocities. Vector field \(\boldsymbol{v}\), magnitude \(|\boldsymbol{v}|\) and components \(v_i\) for \(i=\{x,y,z\}\). This output is only available in analyses of type "Dynamic" or "Transient".

  • A:

    Solid accelerations. Vector field \(\boldsymbol{a}\), magnitude \(|\boldsymbol{a}|\) and components \(a_i\) for \(i=\{x,y,z\}\). This output is only available in analyses of type "Dynamic".

  • Pw:

    Pore-water pressure. Scalar field \(p^w\). This output is only available for finite elements based on the \(\boldsymbol{u}\)-\(p\) formulation discretising the solid displacement \(\boldsymbol{u}\) and the pore water pressure \(p^w\) as primary unknowns.

  • Uw:

    Water displacements. Vector field \(\boldsymbol{U}\), magnitude \(|\boldsymbol{U}|\) and components \(U_i\) for \(i=\{x,y,z\}\). This output is only available for finite elements based on the \(\boldsymbol{u}\)-\(\boldsymbol{U}\) formulation discretising the solid displacement \(\boldsymbol{u}\) and the pore water displacement \(\boldsymbol{U}\) as primary unknowns.

  • Pa:

    Pore-air pressure. Scalar field \(p^a\). This output is only available for finite elements based on the \(\boldsymbol{u}\)-\(p\)-\(p\) formulation discretising the solid displacement \(\boldsymbol{u}\), the pore water pressure \(p^w\) and the pore air pressure \(p^a\) as primary unknowns.

  • RF:

    Reaction forces. Vector field \(\boldsymbol{RF}\), magnitude \(|\boldsymbol{RF}|\) and components \(RF_i\) for \(i=\{x,y,z\}\).

  • Sets:

    Write the defined node sets (name + nodes) to the output file. The set name equals the output name. The nodes of the associated node set are given the (integer) value 1, all other nodes are given the (integer) value 0.

  • S:

    Stress. Single (scalar) components \(\sigma_{ij}\) for \(i,j = \{x,y,z\}\) [F/A]. In case of porous elements \(\sigma_{ij}\) is always the "effective stress".

  • vis_stressij:

    Viscous part of the stress contributed by the "mechanical viscosity" model. Single (scalar) components \(\sigma^{vis}_{ij}\) for \(i,j = \{1,2,3\}\) [F/A]. Only for materials where "*Mechanical viscosity' was defined.

  • E:

    Strain. Single (scalar) components \(\varepsilon_{ij}\) for \(i,j = \{x,y,z\}\) [-]. [\(\varepsilon_{ij}\) is always the total strain, i.e. no distinction between elastic and plastic strain components s made.

  • VOID:

    Void ratio. Scalar \(e\) [-]. This output is only available for porous elements.

  • Sat_eff:

    Effective degree of saturation. Scalar \(S^e\). This output is only available for coupled porous elements.

  • Sat:

    Degree of saturation. Scalar \(S^w\). This output is only available for coupled porous elements with two fluids occupying the pore space.

  • Phantom_Elasticity:

    Part of the stress components (requested by the keyword 'S') contributed by the "phantom elasticity" model. Single (scalar) components \(\sigma^{ph}_{ij}\) for \(i,j = \{1,2,3\}\) [F/A]. Only for materials where "*Phantom elasticity' was defined.

Additional nodal output variables:

  • Con_f:

    Connector force of a connector element. Scalar force acting in the direction of the longitudinal axis of the element. This output is only available for so-called "connector-elements".

Node output variables associated with contact definitions between two (or more) parts (only available in analyses including contacts):

  • Contact:

    Mechanical contact variables.

    • Scalar Normal/Tangential stress \(t_N\), \(t_T\) [Pressure]

    • Scalar Normal/Tangential distance \(g_N\), \(g_T\) [Length]

  • Contact_sdv:

    Contact state variables. Output depends on the chosen constitutive contact model. It is currently only available if the hypoplastic contact model is used.

  • Contact_diagnostic:

    Contact diagnostic variables. The following variables are print to the output file:

    • Scalar contact iteration (0/1/-1) It is 0 prior to the initialization of contacts. 1 if the contact is closed and -1 if the contact is open.

    • Scalar convective coordinate failed (0/1) 0 if the evaluation of the convective coordinate was successful. 1 if the projection failed, indicating problems in the surface definition.

    • Scalar convective coordinate [-] Local element coordinate computed in the minimization of the contact distance

    • Scalar Segment type [-] Type of segment associated with a node using the segmentmortar contact discretisation technique.

Element output

*Output, field, <format 1>, <format 2> [, flush]
*Element, elset = <set name>
<variable 1>, ..., <variable n>
*Integration point, elset = <set name>
<variable 1>, ..., <variable n>

This option is used to write element variables (stored at integration points) to the output database. It must be used as a sub-keyword of the *Output keyword. Set <set name> equal to the element set name for which the output should be defined. In the subsequent line, the output variables are defined.

The following variables are currently available:

  • S:

    Stress. Single (scalar) components \(\sigma_{ij}\) for \(i,j = \{x,y,z\}\) [F/A]. In case of porous elements \(\sigma_{ij}\) is always the "effective stress".

  • vis_stressij:

    Viscous part of the stress contributed by the "mechanical viscosity" model. Single (scalar) components \(\sigma^{vis}_{ij}\) for \(i,j = \{1,2,3\}\) [F/A]. Only for materials where "*Mechanical viscosity' was defined.

  • E:

    Strain. Single (scalar) components \(\varepsilon_{ij}\) for \(i,j = \{x,y,z\}\) [-]. \(\varepsilon_{ij}\) is always the total strain, i.e. no distinction between elastic and plastic strain components s made.

  • VOID:

    Void ratio. Scalar \(e\) [-]. This output is only available for porous elements.

  • Sat_eff:

    Effective degree of saturation. Scalar \(S^e\). [This output is only available for coupled porous elements.

  • Sat_eff:

    Degree of saturation. Scalar \(S^w\). This output is only available for coupled porous elements with two fluids occupying the pore space.

  • Phantom_Elasticity:

    Part of the stress components (requested by the keyword 'S') contributed by the "phantom elasticity" model. Single (scalar) components \(\sigma^{ph}_{ij}\) for \(i,j = \{1,2,3\}\) [F/A]. Only for materials where "*Phantom elasticity" was defined.

  • Sets:

    Write the defined element sets (name + elements) to the output file. The set name equals the output name. The elements of the associated element set are given the (integer) value 1, all other elements are given the (integer) value 0.

  • Mat:

    Write the material names and the associated element set as cell data to the output file. The material name is assigned to the output name. The elements of the associated element set are given the (integer) value 1, all other elements are given the (integer) value 0

Depending on the applied element type and material model, the label SVARS can be replaced by the name of the demanded output variable solemnly available for this specific element type/material model. Possible output variables for different material models can be found here *Material. If the <type> is user, the state variable number has to be directly specified, e.g. Statev1 or Statev20.

Element output variables associated with contact definitions between two (or more) parts (only available in analyses including contacts):

  • Contact:

    Mechanical contact variables.

    • Scalar Normal/Tangential stress \(t_N\), \(t_T\) [Pressure]

    • Scalar Normal/Tangential distance \(g_N\), \(g_T\) [Length]

  • Contact_sdv:

    Contact state variables. Output depends on the chosen constitutive contact model. It is currently only available if the hypoplastic contact model is used.

  • Contact_diagnostic:

    Contact diagnostic variables. The following variables are print to the output file:

    • Scalar contact iteration (0/1/-1) It is 0 prior to the initialization of contacts. 1 if the contact is closed and -1 if the contact is open.

    • Scalar convective coordinate failed (0/1) 0 if the evaluation of the convective coordinate was successful. 1 if the projection failed, indicating problems in the surface definition.

    • Scalar convective coordinate [-] Local element coordinate computed in the minimization of the contact distance

    • Scalar Segment type [-] Type of segment associated with a node using the segmentmortar contact discretisation technique.