Section moments in Abaqus
Section moments in Abaqus
(OP)
thread799-188299: Section force componets (SF)
Hi.
I am having some trouble with determining the SM1 og SM2 in Abaqus for a shell element.
From ABAQUS Analysis User's Manual:
"SM1 Bending moment force per unit width about local 2-axis.
SM2 Bending moment force per unit width about local 1-axis"
The way I read this, SM1 is the bending moment about local 2-axis. When I do some simple tests in Abaqus, I would guess from the results that SM1 was bending about local 1-axis. Am I reading the user manual wrong, or am I doing the tests wrong somehow?
Thank you for your help.
Hi.
I am having some trouble with determining the SM1 og SM2 in Abaqus for a shell element.
From ABAQUS Analysis User's Manual:
"SM1 Bending moment force per unit width about local 2-axis.
SM2 Bending moment force per unit width about local 1-axis"
The way I read this, SM1 is the bending moment about local 2-axis. When I do some simple tests in Abaqus, I would guess from the results that SM1 was bending about local 1-axis. Am I reading the user manual wrong, or am I doing the tests wrong somehow?
Thank you for your help.





RE: Section moments in Abaqus
Shoot for the Moon, even if U miss, U still land among Stars!
RE: Section moments in Abaqus
It may be that my basic understanding is missing, but I find these results strange when following the definition from the manual.
Thank you for helping me out.
RE: Section moments in Abaqus
So now if you want to perfectly bend the element, then you need moment at two ends, namely you need moment in Y direction to bend the element. Also try to plot the results along a path line to visualize the results.
Shoot for the Moon, even if U miss, U still land among Stars!
RE: Section moments in Abaqus
I am agreeing with you when you describe the situation in x-y-z coordinates. But when using the results to compare with the local axis the sentence "SM1 Bending moment force per unit width about local 2-axis." is throwing me off.
As shown in the picture, the local 2-axis is the same direction as x-direction. Therefore, I would assume from the manual description that SM1 is about x-axis. This is not what the results shows.
Again, thanks for helping me out.
RE: Section moments in Abaqus
Also in your figure, why there is high intensity for SM2 near supports? Do the following to rectify your confusion:
redraw the model with normal axis system (default coordinates that Y is in direction of gravity)
use S4R, first get DL and natural frequencies and check with hand calcs to see if your model is sound. Then, apply a point load (something that easier to check against hand calc) and plot the output.
Shoot for the Moon, even if U miss, U still land among Stars!
RE: Section moments in Abaqus
I tried to redraw the model, and was not able to draw it with y-direction in gravity direction because of the drawing-grid. However, I flipped the shell so that global y-direction was in line with the gravity. This is shown in the attached picture along with results for SM1 and SM2 and a overview of the local axis system 1-2-n. The same thing happens, I get largest SM1 about local 1-axis which is not right according to the manual "SM1 Bending moment force per unit width about local 2-axis".
RE: Section moments in Abaqus
Your help is appreciated.
RE: Section moments in Abaqus
your confusing yourself, you need to know that rotating an element does not change its output; the manuals says in the direction of local axes. Have a look at below links which describe basic of outputs for stress (it is for SAP2000 but concept is same and easier description for you to follow)
http://docs.csiamerica.com/help-files/etabs/Menus/...
http://docs.csiamerica.com/help-files/etabs/Output...
Shoot for the Moon, even if U miss, U still land among Stars!
RE: Section moments in Abaqus
Thank you.