Prestressed CMS analysis

Pratik

I am trying to perform Prestressed CMS analysis.

I have created 2 load cases, 1^st with pretension and 2^nd statsub preload with CMS analysis.

Optistruct solve these run correctly but while reviewing result I can see result of 2^nd load case only.

Also the effect of change in stiffness due to pretension also can’t be seen.

Need your help to understand the issue and how to perform pretensioned CMS analysis.

Xiaolei

Hi Pratik,

For the bolt pretension model where you need to apply the pretension force or adjustment, this part cannot be reduced out with DMIG.
In the example as below, if we use STATSUB(PRELOAD) to reference loadcase 1(it has pretension actually). The reduction is completed and dmig can be generated with some difference than the one w/o preload. However, in this setup, we are considering only the contact status change for CMS generation subcase due to the presence of STATSUB(PRELOAD).

 SUBCASE        1

  LABEL pretension

ANALYSIS NLSTAT

  SPC =        1

  NLPARM =       30

  PRETENSION =       26

  NLOUT =       34

  STRESS(OUTPUT2) = YES

$

SUBCASE        2

  LABEL CMS With Preload

  CMSMETH =       31

  STATSUB(PRELOAD) =       1

 

Thanks. 

Xiaolei

Pratik

Hi Xiaolei,

Thank you for the answer.

So in Prestressed CMS analysis, does it consider pretension effect Or is their any way to incorporate effect of pretension in CMS analysis.

 

Thanks,

Pratik