Import NASTRAN File: Element Properties

Description

Elastic Line Element Properties

NASTRAN uses PBAR to define the properties of simple beams defined by CBAR. Straus7 creates a standard beam property with non-structural mass. No section geometry is defined. Straus7 reads the cross section area A, moments of area I11 and I22, torsion constant J, and shear stiffnesses K1 and K2.

NASTRAN uses PBARL to define the properties of simple beams defined by CBAR. Straus7 creates a standard beam property with section geometry and non-structural mass.

NASTRAN uses PBCOMP (as an alternative to PBEAM) to define the properties of beams with uniform cross section defined by CBEAM. Straus7 creates a standard beam property with non-structural mass. No section geometry is defined. Straus7 reads the cross section area A, moments of area I11 and I22, and torsion constant J.

NASTRAN uses PBEAM to define the properties of beams with uniform cross section defined by CBEAM. Straus7 creates a standard beam property with non-structural mass. No section geometry is defined. Straus7 reads the cross section area A, moments of area I11 and I22, torsion constant J, and shear stiffnesses K1 and K2 based on the section properties of the first end.

NASTRAN uses PBEAML to define the properties of beams with uniform cross section defined by CBEAM. Straus7 creates a standard beam property with section geometry, taper based on the section geometry of each end, and non-structural mass.

NASTRAN uses PBEND to define the properties of curved beams defined by CBEND. Straus7 creates a pipe beam property if section geometry is defined, with non-structural mass. Straus7 reads the radius RB and angle THETAB to determine the pipe radius in combination with the GEOM option defined by CBEND.

NASTRAN uses PELAS to define the properties of scalar spring elements defined by CELAS1. Straus7 creates a spring-damper beam property.

NASTRAN uses PROD to define the properties of rod elements defined by CROD. Straus7 creates a truss beam property with non-structural mass. No section geometry is defined. Straus7 reads the cross section area A and torsion constant J.

NASTRAN uses PTUBE to define the properties of thin-walled cylindrical tube elements defined by CTUBE. Straus7 creates a standard beam property with section geometry.

NASTRAN uses PGAP to define the properties of gap or frictional elements defined by CGAP. Straus7 creates a normal type point contact beam property. Straus7 reads stiffness values KA and KB, and friction coefficients MU1 and MU2. The maximum of stiffness values KA and KB is assigned as the Initial Stiffness. The initial gap opening and preload values are ignored.

NASTRAN uses PVISC to define the properties of viscous damper element CVISC. Straus7 creates a spring-damper beam property.

Beam Property Numbering

Straus7 preserves the beam property numbers specified by NASTRAN. Property numbers may be skipped, or out of sequence.

Straus7 gives each new property a name of form "PropertyType N / MAT M", where N is the NASTRAN property ID, M is the ID of the referenced material, and PropertyType is the NASTRAN property type. For example, a PBEAM entry with property ID 12 and material ID 7 will have the name "PBEAM 12 / MAT 7".

Non-Structural Masses

The beam properties PBAR, PBARL, PBCOMP, PBEAM, PBEAML and PROD may include non-structural masses for each corresponding beam. Straus7 applies the non-structural masses to each corresponding CBAR, CBEAM, CBEND or CROD element as a beam non-structural mass attribute.

Tapered Beam Sections

The beam properties PBARL and PBEAML may include tapered beam sections for each corresponding beam. The tapered beam sections are determined from the section geometry defined at each end of the beam element, assuming a linear variation along the beam length. The section geometry is assumed to be uniform if the section geometry is defined at the first end only, or if the section geometry at each end is identical. Straus7 assigns averaged section geometry to the beam property, and applies the taper to each corresponding CBAR or CBEAM element as a beam taper attribute.

Elastic Surface Element Properties

NASTRAN uses PSHEAR to define the properties of shear panels defined by CSHEAR. Straus7 creates an isotropic shear panel plate property with the specified thickness T.

NASTRAN uses PSHELL to define the membrane, bending, transverse shear and coupling properties of thin-shell elements defined by CQUAD4, CQUAD8, CQUADR, CTRIA3, CTRIA6 and CTRIAR. Straus7 creates an isotropic plate/shell plate property with the membrane and bending thicknesses set to the specified thickness T.

If the bending moment of inertia ratio 12I/T3 is not equal to 1.0, Straus7 scales the bending thickness by a factor of the cube root of this value. If the material ID for MID2 is set to 0, the plate type is set to 2D plane stress. If the material ID for MID2 is set to -1, the plate type is set to 2D plane strain.

NASTRAN uses PCOMP to define an N-ply composite material laminate for elements defined by CQUAD4, CQUAD8, CQUADR, CTRIA3, CTRIA6 and CTRIAR. Straus7 creates a laminate plate/shell plate property, laminate property and corresponding ply properties. The Z0 parameter used to describe the distance from the reference plane to the bottom surface is supported.

NASTRAN uses PCOMPG to define an N-ply composite material laminate with global ply identification number. Straus7 creates a laminate plate/shell plate property, laminate property and corresponding ply properties. The GPLYID field is ignored.

NASTRAN uses PLPLANE to define the nonlinear hyperelastic properties of 2D plane strain elements defined by CQUAD4, CQUAD8, CTRIA3 and CTRIA6. Straus7 creates a rubber 2D plane strain plate property.

Plate Property Numbering

Straus7 preserves the plate property numbers specified by NASTRAN. Property numbers may be skipped.

Straus7 gives each new property a name of form "PropertyType N / MAT M", where N is the NASTRAN property ID, M is the ID of the referenced material, and PropertyType is the NASTRAN property type. For example, a PSHELL entry with property ID 12 and material ID 7 will have the name "PSHELL 12 / MAT 7".

Non-Structural Mass

The plate properties PSHEAR, PSHELL and PCOMP may include non-structural masses for each corresponding plate. Straus7 applies the non-structural masses to each corresponding CSHEAR, CQUAD4, CQUAD8, CQUADR, CTRIA3, CTRIA6 or CTRIAR element as a plate non-structural mass attribute.

Elastic Solid Element Properties

NASTRAN uses PSOLID to define the properties of solid elements defined by CHEXA, CHEX20, CPENTA and CTETRA. Straus7 creates an isotropic brick property.

NASTRAN uses PLSOLID to define the nonlinear hyperelastic properties of solid elements defined by CHEXA, CPENTA and CTETRA. Straus7 creates a rubber brick property.

Brick Property Numbering

Straus7 preserves the brick property numbers specified by NASTRAN. Property numbers may be skipped, or out of sequence.

Straus7 gives each new property a name of form "PSOLID N / MAT M", where N is the NASTRAN property ID, and M is the ID of the referenced material. For example, a PSOLID entry with property ID 12 and material ID 7 will have the name "PSOLID 12 / MAT 7".

Mass Element Properties

NASTRAN uses PMASS to define the mass values for scalar mass elements defined by CMASS1.