Common Properties: Linear
Description
Linear material properties commonly found in beam, plate and brick property sets.
Properties
Isotropic
Elastic or Young's Modulus.
Units are Pressure (e.g., MPa, psi).
Bulk modulus of the material, which relates volumetric strain to applied uniform pressure.
Units are Pressure (e.g., MPa, psi).
Mass density of the material.
The density multiplied by the volume defines the element mass and determines it's inertial characteristics.
Units are Mass/Volume (e.g., kg/mm3, lb/in3).
Poisson's ratio of the material.
Dimensionless.
Shear modulus of the material.
Units are Pressure (e.g., MPa, psi).
Coefficient of linear thermal expansion relating temperature change to thermal strain.
Note that the linear and volumetric thermal coefficients are different quantities. The volumetric coefficient is three times the linear coefficient.
Units are 1/Temperature (e.g., 1/C, 1/F).
Thermal conductivity. Rate at which heat will travel through the material.
Units are Energy/Time/Length/Temperature (e.g., J/s/mm/C, Btu/s/in/F).
Amount of energy required to change the temperature of one unit of mass by one degree.
Units are Energy/Mass/Temperature (e.g., J/kg/C, Btu/lb/F).
Area used to calculate thermal stiffness and damping for property types that do not otherwise have an area in their definition.
Applicable to spring-damper, point contact, connection and user-defined beam elements as these elements do not have cross section properties.
Units are Area (e.g., mm2, in2).
Mass used to calculate thermal damping for property types that do not otherwise have a mass or mass density in their definition.
Applicable to point contact and connection elements as these elements do not have structural mass or density properties.
Units are Mass (e.g., kg, lb).
Orthotropic / Anisotropic / User-defined
Properties defined in terms of the local element axes. See Plate Elements: Local Axes and Brick Elements: Local Axes.
Elastic moduli relative to the element's local axes.
Units are Pressure (e.g., MPa, psi).
Poisson's Ratio (ν12 / ν23 / ν31 / ν21 / ν32 / ν13)
Poisson's ratios relative to the element's local axes.
Dimensionless.
Shear Modulus (G12 / G23 / G31)
Shear moduli relative to the element's local axes.
Units are Pressure (e.g., MPa, psi).
Thermal Expansion (α1 / α2 / α3 / α12 / α23 / α31)
Thermal expansion coefficients relative to the element's local axes relating temperature change to thermal strain.
Units are 1/Temperature (e.g., 1/C, 1/F).
Thermal conductivity relative to the element's local axes.
Units are Energy/Time/Length/Temperature (e.g., J/s/mm/C, Btu/s/in/F).
Coefficients of the elastic material matrix.
The full three dimensional anisotropic matrix requires 21 independent non-zero coefficients to define the relationship between stress and strain. Fewer non-zero coefficients are required for other analysis and material types such as 3D orthotropic, 2D plane stress and 2D plane strain.
Units are either Force/Length2 (e.g., N/mm2, lbf/in2) for stiffness matrices, or Length2/Force (e.g., mm2/N, in2/lbf) for compliance matrices.
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Plate Elements (Plate/Shell)
Only 6 of the 21 coefficients are required. The coefficients for the through-thickness direction are not used as the plate is assumed to be in a state of plane stress.
This reduced material matrix is used for both the membrane and bending stiffness matrices of the element. For the membrane stiffness, the material matrix is scaled by the membrane thickness, tm; for the bending stiffness, the material matrix is scaled by tb3/12, where tb is the bending thickenss.
The transverse shear coefficients for thick plates are set independently.
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Plate Elements (2D Plane Stress and 2D Plane Strain)
Only 10 of the 21 coefficients are required. Coefficients for the through-thickness direction are considered.
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Brick Elements
All 21 coefficients are used for the anisotropic case. Some of the coefficients will be zero when the material matrix represents orthotropic or isotropic brick elements.
Transverse Shear (excluding User-defined Plate/Shell)
Coefficients for transverse shear stiffness, relating transverse shear forces to transverse shear strain.
If non-zero, enables the thick plate formulation when used with Tri6/Quad8/Quad9 elements.
Units are Pressure (e.g., MPa, psi).
Type of relationship defined by the material matrix.
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Stiffness
Material defines a stiffness matrix relating strain to stress.
The stiffness matrix is the inverse of the compliance matrix.
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Compliance
Material defines a compliance matrix relating stress to strain.
The compliance matrix is the inverse of the stiffness matrix.
Checks whether the material matrix is singular or not.
The material matrices for laminates are basically the same as those for user-defined plate/shell materials.
For laminates, these matrices are automatically calculated based on the laminate lay-up and the individual ply properties. They are displayed in the Property dialog for reference, but they cannot be edited there. The matrices can only be modified indirectly, by changing the lay-up (LAYOUTS: Laminates) or the individual ply properties (LAYOUTS: Plies).
For user-defined materials, these matrices are entered directly into the Property dialog.
Engineering Data (Ex, Ey, Gxy, νxy)
Effective elastic moduli, shear modulus and Poisson's ratio in the plane of the element, calculated for laminate materials only.
These values are not used in the analysis (the laminate matrices are used directly); they are provided only as a design aid.
Average mass density.
For laminates, it is computed based on the laminate lay-up and the individual ply densities.
Units are Mass/Volume (e.g., kg/mm3, lb/in3)
Membane Thermal Expansion (αx, αy, αxy)
Effective membrane thermal expansion coefficients relative to the element's local axes relating temperature change to membrane thermal strain.
Units are 1/Temperature (e.g., 1/C, 1/F).
Bending Thermal Expansion (βx, βy, βxy)
Effective bending thermal expansion coefficients relative to the element's local axes relating temperature change to thermal curvature.
These are zero for symmetric laminate lay-ups, and are not used when the laminate is assigned to 2D plane stress or 3D membrane elements.
Units are 1/Temperature/Length (e.g., 1/C/m, 1/F/in).
Coefficients of membrane stiffness or compliance matrix.
Stiffness units are Force/Length (e.g., N/mm, lbf/in).
Compliance units are Length/Force (e.g., mm/N, in/lbf).
Membrane/Bending Coupling Matrix [B]
Coefficients of membrane/bending coupling stiffness or compliance matrix.
These are zero for symmetric laminate lay-ups, and are not used when the laminate is assigned to 2D plane stress or 3D membrane elements, or when the Ignore Coupling option is set.
Stiffness units are Force (e.g., N, lbf).
Compliance units are 1/Force (e.g., 1/N, 1/lbf).
Coefficients of bending/curvature stiffness or compliance matrix.
These are not used when the laminate is assigned to 2D plane stress or 3D membrane elements.
Stiffness units are Force×Length (e.g., N·mm, lbf·in).
Compliance units are 1/(Force×Length) (e.g., 1/N·mm, 1/lbf·in).
Coefficients for transverse shear stiffness matrix.
If non-zero, enables thick plate formulation when used with Tri6/Quad8/Quad9 elements.
Units are Force/Length (e.g., N/mm, lbf/in).
Applies only to laminates.
If set, the membrane/bending coupling matrix is excluded from the analysis.
Applies only to laminates.
If set and transverse shear moduli are defined for all plies, an effective transverse shear stiffness is calculated automatically for the laminate.
If not set, the coefficients may be entered manually.
Fluid
Circulation mode penalty parameter.
This is used to control circulation modes in fluid elements.
Dimensionless.
See Materials: Fluid.
Dimensionless.
See Also