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Interpretation of CBUSH stresses

Experimenter
Experimenter

We are processing a linear static structural problem using NX Nastran within NX 8. We were given the NAST and OP2 files for the problem.  The NAST file contains several CBUSH elements.  The "K" values are defined on the PBUSH entries, but no stress recovery "RCV" entries are included!   Nevertheless, when the stresses are plotted for the entire structure, the zig-zag springs are colored with stress values. How should these stress values be interpreted? 

5 REPLIES

Re: Interpretation of CBUSH stresses

Siemens Phenom Siemens Phenom
Siemens Phenom

PBUSH.pngThe defaults for the stress (and strain) recovery coefficients are 1.0. The stress results should then equal the element forces.

 

See the QRG for default values for any field.

 

 

Re: Interpretation of CBUSH stresses

Experimenter
Experimenter

We don't understand why the RCV default values would be used for stress calculation for a CBUSH when the PBUSH RCV flag is not present in our NAST file!

Re: Interpretation of CBUSH stresses

Siemens Phenom Siemens Phenom
Siemens Phenom

The default values are used because that is the definition of "default". The default value noted in the QRG is the value that is used by the program if a particular field in the input file is blank.

Re: Interpretation of CBUSH stresses

Experimenter
Experimenter

Is it true then that the default RCV values are used even when the RCV flag does NOT appear in the NAST file?  Thank you for your help!

Re: Interpretation of CBUSH stresses

Siemens Phenom Siemens Phenom
Siemens Phenom

Yes