DSA

I/O Options and Subcase Information Entry

DSA - Design Sensitivity Analysis Output Request

Description

The DSA command can be used in the I/O Options section to request Design Sensitivity Analysis results in a frequency response analysis.

Format

DSA (TYPE, PEAKOUT, PROPERTY) = SID

Examples

DSA(DISP,PROPERTY)=12

DSA(VELO,PEAKOUT)=45

DSA(ACCE,PEAKOUT,PROPERTY)=23

Argument	Options		Description
TYPE	<DISP,PRES, VELO,ACCE, ERP> Default = DISP		The options are Displacement, Pressure, Velocity and Acceleration, and Equivalent Radiated Power, respectively.

PEAKOUT	Default = blank		If PEAKOUT is present inside the parentheses of the DSA entry, the filtered frequencies from the PEAKOUT card will be considered for DSA results.

PROPERTY	Default = blank	If PROPERTY is present: This indicates that design sensitivities represent the change in design response due to a change in design properties (instead of design variables). If PROPERTY is not present: This indicates that design sensitivities represent the change in design response due to a change in design variables.

SID/ALL	<SID>	SID refers to the ID of a SET of type GRIDC.
SID/ALL	<ALL>	Requested values are output for all relevant entities.

1.	Multiple instances of this card are allowed; if instances are conflicting, the last instance dominates. If this entry is defined above the first subcase then it is applied to all subcases. If it is defined within a specific subcase then it is applied to that subcase only.

2.	If the input deck does not contain any optimization data (apart from DESVAR’s), a MASS objective function is automatically created along with responses and constraints corresponding to the DSA request. If the input deck contains a valid optimization setup, then it is augmented with the DSA request.

3.	In the H3D file, the "SCALE" value is only printed when the PROPERTY argument is not present within the parentheses of the DSA entry. The sensitivities are pre-scaled when the PROPERTY argument is present in the DSA entry, so the scaling factor is not required in the H3D file.

4.	OUTPUT, H3DSENS can be used to include (or exclude) user-defined responses in the DSA output. The table below lists the sensitivities that are output for each option.

Output	Sensitivities requested via the DSA output request (responses are automatically defined)	Sensitivities output from a complete Optimization setup (User-defined/specified responses via DRESP1, DRESP2, DRESP3)
OUTPUT, H3DSENS, USER	Yes	Yes
OUTPUT, H3DSENS, NOUSER	Yes	No

5.	Design variables and their corresponding design properties must be defined in the input deck if sensitivity output is requested through the DSA entry.

6.	DSA output for ERP is available for ALL panels. Set ID (SID) cannot be used and is ignored, if specified.