3.18.2.1 Plotfile Variables
Plotfile variables are defined using the var keyword. This tag takes one parameter, namely the type of the variable.
<var type="<name>"/>
where name is the name of the variable. The following table lists the possible values for name.
| Name | Variable | Description |
| Acceleration | Element | Average element accelerations |
| contact area | Surface | Net contact area across contact interface. Evaluated by integrating the surface area at integration points where the contact pressure is not zero. |
| contact force | Surface | Net contact force across contact interface. Evaluated by integrating the contact traction over the contact surface. |
| contact gap | Surface | Contact gap distance, evaluated at contact surface faces |
| contact penalty | Surface | Contact penalty value |
| contact pressure | Surface | Contact pressure, evaluated at contact surface faces |
| contact stick | Surface | Stick status in stick-slip frictional contact (1=stick, 0=slip). Values between 0 and 1 imply that a fraction of that face is in stick mode. Currently works only with sliding-tension-compression. |
| contact traction | Surface | Contact traction vectors, evaluated at contact surface faces |
| current density | Element | Electric current density, Eq.(4.10.1.5-1) |
| current element angular momentum | Element | The element's total angular momentum at the current configuration. |
| current element center of mass | Element | The element's center of mass at the current configuration. |
| current element kinetic energy | Element | The element's total kinetic energy at the current configuration. |
| current element linear momentum | Element | The element's total linear momentum at the current configuration |
| current element strain energy | The element's total strain energy at the current configuration. | |
| damage | Element | Damage variable (Section 4.6↓) |
| density | Element | The current density |
| deviatoric strain energy density | Element | Deviatoric strain energy density , Eq.(4.1.2-1) |
| displacement | Node | Nodal displacements |
| effective elasticity | Element | The elasticity of the elastic material in a biphasic/triphasic/multiphasic material. |
| effective fluid pressure | Node | fluid pressure for biphasic, biphasic-solute, triphasic, and multiphasic materials. |
| effective shell fluid pressure | Node | fluid pressure for biphasic, biphasic-solute, triphasic, and multiphasic materials of shell domains. |
| effective shell solute concentration | Node | Effective solute concentration for biphasic-solute, triphasic, and multiphasic materials of shell domains. |
| effective solute concentration | Node | Effective solute concentration for biphasic-solute, triphasic, and multiphasic materials. |
| effective fluid pressure | Node | Fluid pressure for biphasic materials, Eq.(4.8-1), or for biphasic-solute, Eq.(4.9-3) and triphasic/multiphasic materials, Eq.(4.10-7) |
| effective solute concentration | Node | Effective solute concentration for biphasic-solute materials, Eq.(4.9-3), and triphasic/multiphasic materials, Eq.(4.10-7) |
| elasticity | Element | Spatial elasticity tensor components |
| electric potential | Element | Electric potential in triphasic/multiphasic materials, Section 4.10↓ |
| element angular momentum | Element | Element total angular momentum |
| element center of mass | Element | Element center of mass |
| element kinetic energy | Element | Element total kinetic energy |
| element linear momentum | Element | Element total linear momentum |
| element strain energy | Element | Element total strain energy |
| element stress power | Element | Element total stress power |
| enclosed volume | Surface* | Volume enclosed by named surface |
| Euler angle | Rigid body | Rigid body Euler angles |
| fiber stretch | Element | Element's average fiber stretch |
| fiber vector | Element | Material fiber vector |
| fixed charge density | Element | Fixed charge density in current configuration, Eq.(4.10-2) |
| fluid acceleration | Element | Fluid acceleration (material time derivative of fluid velocity , Section (4.1.2.5-1) |
| fluid density | Element | Fluid density in fluid and fluid-FSI materials, Eq.(4.14-3) |
| fluid dilatation | Node | Fluid dilatation , Section (4.1.2.5-1)) |
| fluid element angular momentum | Element | Total angular momentum of fluid element |
| fluid element center of mass | Element | Center of mass of fluid element |
| fluid element kinetic energy | Element | Total kinetic energy of fluid element |
| fluid element linear momentum | Element | Total linear momentum of fluid element |
| fluid element strain energy | Element | Total strain energy of fluid element |
| fluid energy density | Element | Average energy density of fluid element |
| fluid flow rate | Surface* | Volumetric fluid flow rate across a named surface (biphasic and multiphasic analyses) |
| fluid flux | Element | Fluid flux in biphasic, Eq.(4.8-2), biphasic-solute, Eq.(4.9-4), and triphasic/multiphasic materials, Eq.(4.10-9) |
| fluid force | Surface | Net fluid force across biphasic (sliding-biphasic), biphasic-solute (sliding-biphasic-solute) and multiphasic (sliding-multiphasic) contact interface. Evaluated by integrating the fluid pressure over the contact surface. |
| fluid force2 | Surface | Alternative calculation of the net fluid force |
| fluid heat supply density | Element | Average heat supply density of a fluid element |
| fluid kinetic energy density | Element | Average kinetic energy densify of a fluid element |
| fluid load support | Surface | The total fluid load support across a named surface |
| fluid mass flow rate | Surface* | Mass flow rate across a named surface, , Section (4.1.2.5-1) |
| fluid pressure | Element | Fluid pressure in biphasic, Eq.(4.8-1), biphasic-solute, Eq.(4.9-3), triphasic/multiphasic materials, Eq.(4.10-7), and fluid materials, Eq.(4.14-2) |
| fluid rate of deformation | Element | Fluid rate of deformation tensor , Section (4.1.2.5-1) |
| fluid shear viscosity | Element | Average shear viscosity of a fluid element |
| fluid strain energy density | Element | Average shear energy density of fluid element |
| fluid stress | Element | Fluid stress , Eq.(4.14-1) |
| fluid stress power density | Element | Fluid stress power , Section (4.1.2.5-1) |
| fluid surface energy flux | Surface | The total energy flux across a named surface for a fluid analysis |
| fluid surface force | Surface* | Net force exerted by a fluid on a named surface, , Section (4.1.2.5-1) |
| fluid surface pressure | Surface* | Average fluid pressure on each face of a surface, evaluated from the nodal values of the fluid dilatation on that face |
| fluid surface traction power | Surface | Net traction power across a named surface of a fluid analysis |
| fluid velocity | Element | Element fluid velocity in fluid and fluid-FSI materials, Section (4.1.2.5-1) |
| fluid volume ratio | Element | Fluid volume ratio , Section (4.1.2.5-1) |
| fluid vorticity | Element | Fluid vorticity, Section (4.1.2.5-1) |
| heat flux | Element | The average heat flux inside an element of a heat-transfer analysis |
| kinetic energy density | Element | The average kinetic energy density in an element |
| Lagrange strain | Element | The average Lagrange strain in an element |
| nested damage | Element | The average damage in an elastic mixture |
| nodal acceleration | Node | The acceleration at the nodes |
| nodal contact gap | Surface | Contact gap distance, evaluated at contact surface nodes |
| nodal contact pressure | Surface | Contact pressure, evaluated at contact surface nodes |
| nodal contact traction | Surface | Contact traction vectors, evaluated at contact surface nodes |
| nodal fluid flux | Element | Fluid flux in biphasic, biphasic-solute, triphasic, and multiphasic materials |
| nodal fluid velocity | Node | Fluid velocity in fluid and fluid-FSI materials |
| nodal relative fluid velocity | Node | Fluid velocity relative to mesh in fluid and fluid-FSI materials |
| nodal stress | Element | The Cauchy stress, projected to the nodes. |
| nodal surface traction | Surface | Contact nodal tractions |
| nodal vector gap | Surface | Contact gap vector at surface nodes |
| nodal velocity | Node | The nodal velocities |
| osmolarity | Element | Element's average osmolarity in biphasic/triphasic/multiphasic analysis |
| parameter | Element | Stores heterogeneous material parameter data |
| pressure gap | Surface | Pressure gap between opposing surfaces in a biphasic contact analysis |
| reaction forces | Node | The nodal reaction forces. |
| receptor-ligand concentration | Element | Receptor-ligand concentration in a biphasic-solute analysis. |
| referential fixed charge density | Element | Referential fixed charge density , Eq.(4.10-2), which may evolve with chemical reactions, Eq.(4.11.1-10) |
| referential solid volume fraction | Element | Referential solid volume fraction , which may evolve with chemical reactions, Eq.(4.11.1-9) |
| relative fluid velocity | Element | Average element fluid velocity relative to mesh in fluid and fluid-FSI materials |
| relative volume | Element | Relative volume |
| rigid acceleration | Rigid body | Rigid body center of mass acceleration |
| rigid angular acceleration | Rigid body | Rigid body angular acceleration |
| rigid angular momentum | Rigid body | Rigid body angular momentum |
| rigid angular position | Rigid body | Rigid body rotation pseudo-vector |
| rigid angular velocity | Rigid body | Rigid body angular velocity |
| rigid force | Rigid body | Total force applied to the rigid body |
| rigid kinetic energy | Rigid body | Rigid body kinetic energy |
| rigid linear momentum | Rigid body | Rigid body linear momentum |
| rigid position | Rigid body | Rigid body center of mass position |
| rigid rotation vector | Rigid body | Rigid body rotation pseudo-vector |
| rigid torque | Rigid body | Rigid body moment |
| rigid velocity | Rigid body | Rigid body center of mass velocity |
| sbm concentration | Element | Average element solid-bound molecule concentration |
| sbm referential apparent density | Element | Average element solid-bound molecule referential apparent density |
| shell director | Element | The shell director |
| shell relative volume | Element | Relative volume of shell element |
| shell strain | Element | Average strain in shell element |
| shell thickness | Node | Shell thickness |
| solute concentration | Element | Solute concentration in biphasic-solute materials, or in triphasic/multiphasic materials |
| solute flux | Element | Solute flux in biphasic-solute materials, Eq.(4.9-4), or in triphasic/multiphasic materials, Eq.(4.10-9). |
| specific strain energy | Element | Average element specific strain energy |
| SPR principal stress | Element | Principal stress values obtained via SPR projection |
| SPR stress | Element | Cauchy stress obtained via SPR projection |
| SPR-P1 stress | Element | Cauchy stress obtained via SPR projection (first-order projection) |
| strain energy density | Element | Strain energy density |
| stress | Element | Cauchy stress |
| surface traction | Surface | Nodal surface tractions of nodes on a contact surface |
| uncoupled pressure | Element | The pressure of an uncoupled material |
| ut4 nodal stress | Element | Stresses at the nodes of the UT4 element |
| vector gap | Element | The vector gap at nodes of a contact surface |
| velocity | Node | Nodal velocities (fluid nodal velocities in fluid analyses) |
| volume fraction | Element | Average element volume fraction of a solid mixture |
| in-situ target stretch | Element | the fiber stretch induced by the initial prestrain gradient |
| prestrain stretch | Element | the stretch induced by the effective prestrain gradient |
| prestrain correction | Element | the 3x3 prestrain correction tensor |
| SPR prestrain correction | Element | The 3x3 prestrain correction tensor (recovered with SPR) |
The following example stores nodal displacements and element stresses.
Example:
<plotfile type="febio"> <var type="displacement"/> <var type="stress"/> </plotfile>
As of FEBio 2.4, additional information can be added in the type description of the variable definition. The general format is as follows.
<var type="name[filter]=alias"/>
The plot filter is defined by appending the name of the plot variable with the filter inside square brackets. Some plot variables require this to resolve possible ambiguities. For example,
<var type="solute concentration['solute1']"/>
This example will store the solute concentration of a solute named `solute1' to the plot file.
The optional alias can be used to rename the variable. For example,
<var type="solute concentration['Na']=Na concentration"/>
This variable will store the solute concentration of a solute named `Na' to the plot file using the name `Na concentration'. This is the name that will be shown in PostView for instance.
Some variables require the specification of a named surface (* in above table). For example,
<var type="fluid surface force" surface="airfoil"/>
The named surface should be described in a Surface element (Section 3.6.5↑) within Mesh (Section 3.6↑).