Properties physical types

The structural properties

Theses properties are applied on structural elements and have the particularity to all have a MATERIAL characteristic. This characteristic is a pointer which references the explicit material entity which should be under the material explicit set. Indeed, in the update mechanism of the field model, the material set (and therefore its child material) is always updated before the property set (and therefore before the child properties). For all the structural properties listed here after, the MATERIAL characteristic is present but not in the list of characteristic.

PROPERTY_BAR_3D defines a bar element. A bar element is a 1D element that only strain in traction and compression. This property is axis-symmetric. The X axis is parallel to the bar axis and the cross-sectional characteristics are constant in X. Physical characteristics is:
- CROSS_SECTIONAL_AREA is the constant area of the section computed in the orthogonal plane of the X axis.
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PROPERTY_BEAM_3D defines the properties of the straight beam element. The X axis is parallel to the beam axis and the beam cross-sectional characteristics are constant in X. Transverse shear effects and torsion center are taken into account. Arbitrary rigid offsets (one vector at each structure node) are also taken into account. To clarify the axis vocabulary, refer to the following scheme:

Physical characteristics are:
- CROSS_SECTIONAL_AREA is the constant area of the section computed in the orthogonal plane of the X axis.
- AREA_MOMENT_OF_INERTIA is the symmetrical tensor expressed in the real element axis, usually expressed in its principal axis (i.e. the tensor is diagonal); if so, Ixx is the torsion stiffness and Iyy an Izz the bending stiffness.
- AREA_SHEAR_RATIO_XY is the ratio of the total cross-sectional area over the effective shear area in the local XLocYLoc plane (should always be greater than 1).
- AREA_SHEAR_RATIO_XZ is the ratio of the total cross-sectional area over the effective shear area in the local XLocZLoc' plane (should always be greater than 1).
- OFFSET: 6 components of the 2 rigid offset vectors in m, each oriented from a structural node to the corresponding end of the physical beam, with respect to the element reference frame by default.
- SHEAR-CENTER: 2 coordinates of the torsion (shear) center in m, expressed in the YLocZLoc axis.
- ORIENTATION_VECTOR same as for the element (Element value is collected by priority)
- ORIENTATION_NODE same as for the element (Element value is collected by priority)
- ORIENTATION_POINT same as for the element (Element value is collected by priority). Note: Only one of the three last characteristics should be defined.
- TORSIONAL_STIFFNESS_PARAMETER is the torsion stiffness parameter.
- DEGREES_OF_FREEDOM two bit arrays (6 bits for each) to release a combination of the 6 degrees of freedom at each end (Element value is collected by priority).
- WARPING_NODE_A Node identifier that define the warping at the beginning of the beam.
- WARPING_NODE_B Node identifier that define the warping at the end of the beam.
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PROPERTY_CURVED_BEAM_3D: Property applied only on ELEMENT_CURVED_BEAM_3D_BAR2. For characteristic description, refer to the here above PROPERTY_BEAM_3D.
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PROPERTY_SHELL_3D
- THICKNESS Note that if no SURFACE_OFFSET characteristic is defined the thickness is equally distributed above and under the element.
- SURFACE_OFFSET same as for the element (Element value is collected by priority).
- MATERIAL_ANGLE same as for the element (Element value is collected by priority).
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PROPERTY_MEMBRANE_3D
- THICKNESS: See PROPERTY_SHELL_3D thickness definition.
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PROPERTY_SHEAR_PANEL_3D
- THICKNESS: See PROPERTY_SHELL_3D thickness definition.
- ROD_AREA_RATIO: Two scalar to simulate virtual stiffening bars along the quadrangle shear element edges. The scalars is the ratio of the area of the quadrangle over the cross-sectional area of the virtual bars. Four virtual bars are simulated with this characteristic but only two ratios are given as inputs as opposite bars have the same properties by pairs??
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PROPERTY_COMPOSITE_SHELL_3D. Used to model a 2D stack-up of composites.
- NB_LAMINATES: Integer defining the number of laminate.
- MATERIAL: Characteristic listed here because unlike other structural properties, the number of pointers to explicit materials (repeat on the characteristic) has to be equal to the number of laminate defined here above.
- THICKNESS: in m. Thickness of all the layers. The repeat on this characteristic has to be equal to the number of laminates.
- ANGLE: in radian. Angle of the fiber with respect to the reference axis (see here after scheme). Useful, of course, only when using non-isotropic material
- MATERIAL_ANGLE: In radian. Angle between the first edge of one element and the reference axis (see here after scheme).
- LOCAL_AXIS: Local axis of the element expressed in the reference axis??. Note: Only one of the two former characteristic should be defined.
- PLY_ID: Set of NB_LAMINATES integers that can be optionally stored for post processing purpose only (e.g. display the stresses of the layer of PLY_ID 2 in the entire model).
Here is a scheme showing the computation and meaning of the different axis:

On this scheme, the reference axis is chosen by the user and not stored in the field model. In case the X and Y axis of the reference axis is not in the element plane, they are projected in the plane axis. The element is in blue on the scheme with the node numbers (local to the element). The first edge which is used to define the MATERIAL_ANGLE characteristic is the oriented edge that goes from node 1 to node 2 of the element. Note that in this particular scheme, the normal to the element would be positively oriented in the same sense as Z. Note also that the number of ANGLE characteristics defined has to be equal to the number of laminates, as the number of MATERIAL_ANGLE defined should be equal to the number of elements on which the property is applied (if only one is defined, i.e. repeat=1, then the unique value is taken for all the elements).

On the scheme, the red stripes shows the orientation of one laminate.

With this model one cannot under the same entity property have a different stack-up for two elements on which the property is applied.

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The cinematic properties

Theses properties are applied on cinematic elements. No MATERIAL characteristic is associated to on any of these properties.

PROPERTY_CONSTRAINT_3D_RIGID:
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- DEGREES_OF_FREEDOM: Only one bit array to release the DOFs at the slave node??
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PROPERTY_CONSTRAINT_3D_AXIAL:
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PROPERTY_CONSTRAINT_3D_MEAN:
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- DEGREES_OF_FREEDOM: Only one bit array to release the DOFs at the slave node??
- WEIGHTING_FACTOR ??
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PROPERTY_SPRING_3D:
- TRANSLATIONAL_STIFFNESS: Translational spring constants with respect to the local reference frame, expressed as a diagonal tensor.
- ROTATIONAL_STIFFNESS: Rotational spring constants with respect to the local reference frame, expressed as a diagonal tensor.
- LOCAL_AXIS: Same as for the element (Element value is collected by priority).
- DEGREES_OF_FREEDOM: Two bit arrays to release the DOF at each end of the spring element.
- ROTATIONAL_DAMPING: Three real values to define the damping in each direction defined by the LOCAL_AXIS definition.??
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PROPERTY_SPRING_BEAM_3D:
- TRANSLATIONAL_STIFFNESS: Translational spring constants with respect to the local reference frame, expressed as a diagonal tensor.
- ROTATIONAL_STIFFNESS: Rotational spring constants with respect to the local reference frame, expressed as a diagonal tensor.
- LOCAL_AXIS: Same as for the element (Element value is collected by priority).
- AREA_MOMENT_OF_INERTIA: See beam property
- MASS_INERTIA: ??
- STRUCTURAL_DAMPING:??
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PROPERTY_CONSTRAINT_3D_CONTACT :
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- ORIENTATION_VECTOR See beam properties for more information
- ORIENTATION_POINT See beam properties for more information
- ORIENTATION_NODE See beam properties for more information.
- CLEARANCE: in m. Rigid contact bar element with 2 nodes are used to impose a minimal clearance between the nodes in the direction of the segment joining the initial positions of these nodes. The clearance is maximum distance by which the clearance projected on this segment can be reduced (this parameter can also be interpreted as an initial clearance between nodes, supposing that they are allowed to eventually come in contact). Its use is recommended when some part of a structure may be brought into contact with some other part of the structure. Contact elements are then defined for pairs of nodes from the two parts.
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PROPERTY_CONSTRAINT_3D_CABLE:
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- ORIENTATION_VECTOR See beam properties for more information
- ORIENTATION_POINT See beam properties for more information
- ORIENTATION_NODE See beam properties for more information.
- CLEARANCE: in m. See PROPERTY_CONSTRAINT_3D_CONTACT.
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PROPERTY_CONTACT_3D:
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- ORIENTATION_VECTOR See beam properties for more information
- ORIENTATION_POINT See beam properties for more information
- ORIENTATION_NODE See beam properties for more information.
- CLEARANCE: in m. See PROPERTY_CONSTRAINT_3D_CONTACT.
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PROPERTY_CONSTRAINT_3D_FITTING:
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- ORIENTATION_VECTOR See beam properties for more information
- ORIENTATION_POINT See beam properties for more information
- ORIENTATION_NODE See beam properties for more information.
- OVERLAP: in m. Distance of interference at the initial state. The behavior is comparable to a PROPERTY_CONSTRAINT_3D_CONTACT with a negative clearance.
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PROPERTY_CONSTRAINT_3D_TIGHTENING:
- LOCAL_AXIS: Local axis definition (Element value is collected by priority)
- ORIENTATION_VECTOR See beam properties for more information
- ORIENTATION_POINT See beam properties for more information
- ORIENTATION_NODE See beam properties for more information.
- TIGHTENING_FORCE: in N. Force transmitted by the element.??

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The RTM* properties

PROPERTY_RTM_RUNNER
- ISOTROPIC_PERMEABILITY : The material is implicit. The principal material characteristic is the the permeability which is calculated from the geometrical parameters.
- THICKNESS
- FIBER_CONTENT : Characteristic which represents the percentage of volumic space occupied by the fibers. The rest is in most of the case empty or eventually it can be filled with resin. For a runner, the percentage is most of the case Null but in some cases the user may like to precise a non-null value.

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PROPERTY_RTM_SHELL
- MATERIAL : Characteristic listed here because unlike other structural properties, the number of pointers to explicit materials (repeat on the characteristic) .
- THICKNESS
- FIBER_CONTENT : See Property_RTM_Runner.
- FIBER_DIR_1 : Allow to store the fiber direction in the first direction
- FIBER_DIR_2 : Allow to store the fiber direction in the second direction
- FIBER_DIR_3 : Allow to store the fiber direction in the third direction
  - Why do we need these fiber directions? If we take the example of a fabric that has been sheared, all the fibers are not necessary orthogonal.
- PRINCIPAL_PERMEABILITY : At the origin this matrix was used to store the full permeability values in the global axis on each element.
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PROPERTY_RTM_SHELL_CPD
- THICKNESS
- FIBER_CONTENT See Property_RTM_Runner.
- FIBER_DIR_1 : Refer to PROPERTY_RTM_SHELL
- FIBER_DIR_2
- FIBER_DIR_3
- PRINCIPAL_PERMEABILITY
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PROPERTY_RTM_SOLID
- MATERIAL
- FIBER_CONTENT See Property_RTM_Runner.
- FIBER_DIR_1 : Refer to PROPERTY_RTM_SHELL
- FIBER_DIR_2
- FIBER_DIR_3
- PRINCIPAL_PERMEABILITY

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* Resin Transfer Molding

The Other Properties

PROPERTY_FLUID_3D No characteristic associated to this entity.
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PROPERTY_BEAM_3D_CURVED
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PROPERTY_SHELL_3D_COMPOSITE
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PROPERTY_DAMPER_3D_THERMAL
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MATERIAL_ISOTROPIC_THERMAL
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PROPERTY_CONSTRAINT_3D_SPRING_DAMPER??
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PROPERTY_CONSTRAINT_3D_SPRING_DAMPER_FREQUENCY_DEPENDENT??
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PROPERTY_DAMPER_3D??
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PROPERTY_DAMPER_THERMAL??
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PROPERTY_ACOUSTIC_3D ??
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PROPERTY_MASS_3D
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PROPERTY_TFA_SHELL

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