Solver-specific considerations for solid property calculations

The calculations that the Solid Property Check command performs vary slightly depending upon your specified solver and selected element type.

Nastran considerations

• The Solid Properties Check command uses the consistent mass matrix formulation to compute the model's solid properties. As a result, the solid properties are computed to match the results of the Nastran Grid Point Weight Generator when the parameter PARAM,COUPMASS,1 is specified in the Nastran input file.

• Axisymmetric models in the Simcenter Nastran environment can lie in the XY plane, where the X-axis is the axis of revolution. They can also lie in the ZX plane, where the Z-axis is the axis of revolution.

• The Solid Properties Check command treats Simcenter Nastran chocking elements (CCHOCK3, CCHOCK4, CCHOCK6, and CCHOCK8) as axisymmetric elements in the solid properties calculations. The Solid Properties Check command also takes into account the gap thickness for chocking elements.

• When you select the Solid Properties Check command from a Simulation file, and the active solution contains one or more Non-Structural Mass simulation objects or Protective Layers simulation objects, the software includes the weight of lumped and distributed masses defined with those objects in the solid property calculations.Note: The Non-Structural Mass command in Pre/Post corresponds to the Nastran NSM, NSM1, NSML, and NSML1 bulk data entries.

• The Solid Properties Check command does not compute the solid properties of CBEND elements.

ANSYS considerations

• For structural mass (MASS21) elements, the Solid Properties Check command does not use the MASSY, and MASSZ concentrated mass components in the solid properties calculations regardless of the specified value of KEYOPT(3). This means that the software only uses the MASS (or MASSX) concentrated mass component or the IXX, IYY, and IZZ rotary inertias about the element coordinate axes to perform the calculations.

• For tapered beam (BEAM44) elements, Solid Properties Check uses the average of the cross-sectional areas at end 1 (node I, or fore section) and end 2 (node J, or aft section) in the solid property calculations.

• For solid laminate (SOLSH190, SOLID186, SOLID191) elements, the Solid Properties Check command ignores the ply definition. The software bases the calculations on the actual volume of the solid element defined by its geometry and the material specified in the element's mesh collector properties.

Abaqus consideration

For solid laminate elements (SC6R and SC8R), the Solid Properties Check bases its calculations on the actual volume of the solid element as defined by its geometry and the average material density specified in the element's ply material definition.

Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal considerations

The Solid Properties Check command calculates the surface area for convection and radiation differently, depending upon the element type:

• For 3D (solid) elements, the software uses the free faces of the elements for the surface area calculation. It does not include element faces that share nodes with other 3D element faces.

• For 2D (shell or plate) elements, the software uses the area of both sides of the element for the surface area calculation.

• For 1D (beam or duct) elements, the software uses the perimeter of the beam section multiplied by the length of the beam element for the surface area calculation.

• For 0D elements, the software uses the area of a sphere of the specified Diameter value on the element's associated physical property table for the surface area calculation.

You can use Solid Properties Check to calculate the thermal capacitance of your model (thermal capacitance = mass * specific heat). The Solid Properties Check command reports three different values for thermal capacitance:

• Structural mass capacitanceWith this calculation, the software calculates the mass based on the specified Mass Density of the elements' assigned material multiplied by the volume of the elements.

• Nonstructural mass capacitanceWith this calculation, the software calculates the mass using the specified nonstructural mass in the elements' assigned physical property table.

• Total thermal capacitanceWith this calculation, the software calculates the total capacitance as the sums of the calculated structural and nonstructural mass capacitance.

Learn more

Calculating solid properties

Understanding the solid property calculations

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

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Solver-specific considerations for solid property calculations, Simcenter 3D 2021.1 Series

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