topic Instabilities and matrix not definate in Robot Structural Analysis Forum

Instabilities and matrix not definate

Anonymous — Wed, 22 Nov 2017 16:36:07 GMT

I'm having difficulty in getting my model working. There are innumerable instabilities and I cant figure out what I'm doing wrong?

I believe that as a result of these instabilities I'm having problems with 'matrix note definate' and subsequent non-convergance.

What am i doing wrong?

Re: Instabilities and matrix not definate

Artur.Kosakowski — Thu, 23 Nov 2017 11:21:48 GMT

Hi @Anonymous

IMHO there are too many releases.

I blocked RX in their definitions and used 10% partial elastic releases for RZ. In addition I blocked RXZ at supports and set Full Newton-Raphson method.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

Re: Instabilities and matrix not definate

Anonymous — Thu, 23 Nov 2017 11:40:18 GMT

Thank you Artur, I shall have to explore this solution more so I better understand it, but the model certainly works and the results (moments etc.) are very much in line with expectations.

Thank you again.