The unv file must be formatted according to the standard developed by the SDRC in the 60s-70s that is outlined at the University of Cincinnati – Structural Dynamics Research Laboratory (UC-SDRL) site.
The unv file is structured in datasets split by -1 symbols that can appear in any order.
The following datasets are mandatory for both MAC and FRF Calculators. If they are not found in the unv file the MAC Calculator will not work:
Either Dataset 15 or 2411 (Node coordinates), but not both in the same unv file.
The following dataset is mandatory for the MAC Calculator:
Dataset 55 (Modal Parameters). The following options are supported:
Model Type (record 6, field 1):
Structural: 1
Analysis Type (record 6, field 2):
Normal Modes: 2
Complex Modes: 3
Data Characteristic (record 6, field 3):
3 DOF Global Translation Vector: 2
6 DOF Global Translation and Rotation Vector: 3
Specific Data Type (record 6, field 4):
Displacement: 8
Velocity: 11
Acceleration: 12
Data Type (record 6, field 5):
Real: 2
Complex: 5
The following dataset is mandatory for the FRF Calculator:
Dataset 58 (Function at Nodal DOF). The following options are supported:
DOF Identification (record 6, field 1):
Frequency Response Function: 4
Load Case Identification Number (record 6, field 4):
Single Point Excitation: 0
Response (Output) Node and Reference (Input) Node (record 6, fields 6 and 9):
Any node number defined in the compulsory node coordinates dataset.
Response (Output) Direction and Reference (Input) Direction (record 6, fields 7 and 10):
+X Translation: 1
-X Translation: -1
+Y Translation: 2
-Y Translation: -2
+Z Translation: 3
-Z Translation: -3
+X Rotation: 4
-X Rotation: -4
+Y Rotation: 5
-Y Rotation: -5
+Z Rotation: 6
-Z Rotation: -6
Ordinate Data Type (record 7, field 1):
Real, single precision: 2
Real, double precision: 4
Complex, single precision: 5
Complex, double precision: 6
Abscissa spacing (record 7, field 3):
Uneven: 0
Even: 1
Abscissa Data Characteristics (record 8, field 1):
Frequency: 18
Rpm: 19
Ordinate Numerator (Output) Data Characteristics (record 9, field 1):
Displacement: 8
Velocity: 11
Acceleration: 12
Ordinate Denominator (Input) Data Characteristics (record 10, field 1):
Excitation Force: 13
The following datasets are optional. If they exist in the model, the MAC or FRF Calculators use them, and if they do not exist the default workaround applies:
Dataset 164 (Units). If Dataset 164 is present, the Units property under File 2 Options in the MAC Calculator or under UNV Data in the FRF Calculator should be scoped to Dataset 164 (unv file). If it is not present, the Units property should be scoped to the applicable length unit of the file.
Either Dataset 2420 or Dataset 18 (Coordinate Systems). If neither is present, all Modal parameters are assumed to be expressed in the Global Coordinate System.
Dataset 82 (Tracelines). This dataset is only employed to display the unv model.
Dataset 2412 (Mesh). This dataset is only employed to display the unv model. Only the display of linear 1D, 2D and 3D elements (beams, tris, quads, tets and hexas) is supported.
If neither Dataset 82 nor 2412 are present in the unv file, the unv model is displayed as a point cloud in the Geometry pane.