Non liner quasi static analysis

lerik

I want to apply a pretension in a 1D bolt and i need to define a new load step. I have seen in some tutorials that i should define a new load step with the type --> non linear quasi static.

I am using hypermesh optistruct 2019 and I don't know why I don't have this type in my options. I am doing something wrong? I have other options to define this bolt pretension?

lerik

If I use the non liner static type, I have the following error:

 

*** ERROR # 941 ***
 NON-CONVERGENT NONLINEAR ITERATIONS FOR SUBCASE 1

 Suggestions:
 * Large nonlinear errors indicate that the model may have insufficient support
   - check the data (ideally the model should be stable without gap elements).
   Or try stabilized version of expert system: PARAM,EXPERTNL,CNTSTB.
 
 I forgot to comment that I want to calculate the displacement between two surfaces (one with solid elements and the other one with surfaces) joined by a bolt and having a coefficient of friction between them.
  

FaroukM

Altair Forum User said:

I want to apply a pretension in a 1D bolt and i need to define a new load step. I have seen in some tutorials that i should define a new load step with the type --> non linear quasi static.

I am using hypermesh optistruct 2019 and I don't know why I don't have this type in my options. I am doing something wrong? I have other options to define this bolt pretension?

Hi Ierik, 

 

There is a nice tutorial regarding pretension. 

Please find it in the following link /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' /> 

https://altairhyperworks.com/hwhelp/Altair/2017/help/os/topics/solvers/1d_3d_pretensioned_bolt_analysis_of_ic_engine_components_r-1.htm#Z_1d_3d_pretensioned_bolt_analysis_of_ic_engine_components_r

 

Cheers, 

FaroukM

Altair Forum User said:

If I use the non liner static type, I have the following error:

 

*** ERROR # 941 ***
 NON-CONVERGENT NONLINEAR ITERATIONS FOR SUBCASE 1

 Suggestions:
 * Large nonlinear errors indicate that the model may have insufficient support
   - check the data (ideally the model should be stable without gap elements).
   Or try stabilized version of expert system: PARAM,EXPERTNL,CNTSTB.
 
 I forgot to comment that I want to calculate the displacement between two surfaces (one with solid elements and the other one with surfaces) joined by a bolt and having a coefficient of friction between them.
  

 

Write to me if you need the FE model /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' /> 

lerik

Thank you for your reply Farouk Maaboudallah, the problem is that I don't have the non linear quasi static type in my panel options and as a consequence, I think, I don't have the CNTNLSUB entry. Do you KNow what can I do?

Thanks

FaroukM

Altair Forum User said:

Thank you for your reply Farouk Maaboudallah, the problem is that I don't have the non linear quasi static type in my panel options and as a consequence, I think, I don't have the CNTNLSUB entry. Do you KNow what can I do?

Thanks

 

Why you don't have it ? 

If you create a new 'Load Steps' you will not see Subcase Definition ? 

lerik

 

I only have this options. Can I do it with any of this types?

 

<?xml version="1.0" encoding="UTF-8"?>

FaroukM

Altair Forum User said:

 

I only have this options. Can I do it with any of this types?

 

<?xml version="1.0" encoding="UTF-8"?>

 

Yeah you have it. It's non-linear static (index 5x2)) 

Sachin_21833

Hi, I'm running a bolt pretension analysis(nonlinear quasi static)But I'm getting this error. Error #4965 Maximum number of time increment cutbacks reached,analysis aborted, Any suggestions. Thank you Error #5905 Severe element distortion detected.

Adriano Koga_20259

Sachin_21833 said:

Hi, I'm running a bolt pretension analysis(nonlinear quasi static)But I'm getting this error. Error #4965 Maximum number of time increment cutbacks reached,analysis aborted, Any suggestions. Thank you Error #5905 Severe element distortion detected.

there is something wrong with your convergency.

It might related to a couple different factors, such as "pointy contacts".

 

You need to give more details of your model, and share the .,out file.

 

Also go though this post for some insights:

https://community.altair.com/community?id=community_blog&sys_id=538764ab1b3790d4a5f742eddc4bcba4