cancel
Showing results for 
Search instead for 
Did you mean: 

SOL 601 Multiple Bolt Preload

Experimenter
Experimenter

Hello All,

 

I posted a week ago about a problem with my lap joint model.

https://community.plm.automation.siemens.com/t5/NX-Nastran-Forum/SOL-601-Lap-Joint-Convergence-Probl...

 

I have resolved my problem, but have now encountered another problem.

The model you see is two plates fastened together by two fasteners (all parabolic brick elements). I am having problems applying preload to more than one fastener. I only am able to get one fastener to work properly. The model solves at 100% of the load.

 

The plate has fixed ends on both sides with T2 constraint down the center of the plates because this is a symmetric model, which I only modeled half.

 

Lap Joint.JPG

Below is a picture of the scaled deformation of the bolt preload with the fastener that is preloading correctly.

Fastener 1.JPG

 

I have tried applying the preload the a second fastener. I have checked my contacts several times and have made sure I have the local coordinate systems set up properly with the correct preload direciton. Below is a picture of the bolt that is not preloading right.

 

Fastener 2.JPG

 

It appears that the software is trying to apply preload at the center of the bolt (the bolt region is the center two element rows of the bolt), but it seems to not distribute the load right. I believe the contacts are set properly, but there is something wrong with the local coordinate system.

 

I've attached a dat file of the model. The model will only have bolt preload on the 2nd fastener (I tried to isolate the problem by applying bolt preload to only one fastener).

 

Has anyone ever had this issue or know how to resolve this problem?