Tools | Scaling Menu

This menu contains commands for converting Residue to UMM mode shapes, UMM to Residue mode shapes, and scaling un-scaled shapes using a set of scaled shapes.

Modal Model

Both Residue and Unit Modal Mass (UMM) mode shapes are called a Modal Model because they are both are scaled in a manner which preserves the mass (inertial) and elastic (stiffness) properties of a structure, and hence all of its dynamic properties.  Since these Modal Models preserve all of the dynamic properties of the structure they can be used for

  1. FRF synthesis

  2. Calculation of MIMO Outputs due to Inputs, and Inputs due to Outputs

  3. SDM

  4. FEA Model Updating

Tools | Scaling | UMM to Residue Shapes

Re-scales a set of UMM mode shapes into Residue mode shapes.

UMM Mode Shape:  A mode shape that has been scaled to preserve the mass & stiffness properties of a structure
A set of UMM mode shapes is also called a Modal Model.
Each component (M#) of a UMM mode shape has only a Roving DOF.  .

When this command is executed in a Shape Table containing UMM mode shapes, the following dialog box is opened,

You must select at least one Reference DOF for re-scaling the UMM mode shapes into Residue mode shapes.

Tools | Scaling | Residue to UMM Shapes

Re-scales a set of Residue mode shapes into UMM mode shapes.  

Residue Mode Shape:  A mode shape that has been scaled to preserve the mass & stiffness properties of a structure.
A set of Residue mode shapes is also called a Modal Model.
Each component (M#) of a Residue mode shape has both a Roving DOF and a Reference DOF.  .

When this command is executed in a Shape Table containing Residue mode shapes with multiple Reference DOFs, the following dialog box is opened,

You must select at least one Driving Point Residue for each mode to re-scale it to a UMM mode shape..

Tools | Scaling | Un-Scaled to Scaled Shapes

Re-scales a set of un-scaled shapes using another set of scaled shapes. This command is useful for re-scaling a set of un-scaled OMA mode shapes, using one of the following sets of scaled mode shapes,

  1. A set of FEA mode shapes that are scaled as UMM mode shapes

  2. A set of EMA mode shapes that are scaled as Residue or UMM mode shapes

Each shape in the Shape Table of un-scaled shapes must have a shape in the Shape Table of scaled shapes that is co-linear with it. Two shapes are co-linear of their MAC is close to "1".
Only shapes with some matching DOFs between the two sets of shapes are required.
You must select at least one Driving Point Residue for each mode to re-scale it to a UMM mode shape.
Modal frequency & damping are no considered.