Singularity detected

[y32k]

Just about everytime I run a model I create, it detects a singularity or a non-positive definite. I've tried the suggestions given by the respective help topic but they never work. The only way I've found to solve the issue is to find that node and remesh around it. I usually do that to about 10 to 15 times before it will run without any error messages. Is there something I'm not doing properly when constructing the model? Is there an easier way to fix the problem than remeshing the local area? The model has only shell and beam elements.

 

[40818]

Could you elaborate on the problem please??

 

[y32k]

I made a model using plate and beam elements. When I go to analyze it, one of two errors comes up. Either a singularity or a non-positive definite is detected. These occur at random locations throughout the model.

 

[40818]

Think you might have mechanisms in your model. You are equivalencing arnt you?? Have you checked your F06 data??

Have a look at the thread below

thread727-85105

 

[hansm2]

Try running a normal modes analysis to see what parts of the model are flying away or hinging which would indicate an area which is not properly constrained.

 

[y32k]

I've been trying to do that since I read the thread above (thanks 40818). I can't get that to work either. The error I get is the ID for SDAMP is out of range. It currently is set to 0. I did make a simple model and ran a normal modes analysis on it, and SDAMP is nowhere in the input file. I can't figure out where it's comming from.