Performing nonlinear analysis by Ansys APDL with the application of two loads simultaneously

[RMANERA]

Hi,

I am performing a nonlinear geometric and material analysis by Ansys APDL on a tube with the application of two loads simultaneously with the respective values:

PC = 150 kN (Axial Compression)
PP = 0,26 kN/cm² (external lateral pressure)

Below are the settings for the analysis in Ansys:

TIME,150
NSUBST,50,1000,10
ARCLEN,ON,25,0.001
ARCTRM,U,25,0,UX
AUTOTS,OFF

The relationship between the two loads are quite different.

What precautions do I have to take when working with more than one load?

When I applied TIME,150 what is the program procedure with PP loading?

 

[rickfischer51]

First, if this is a simple static analysis without time dependent material properties (creep, for instance), TIME,150 means nothing. For a static analysis TIME is just an integer identifying a load step. Second, if you issue a AUTOTS,OFF command after NSUBST,50,1000,10, you will get 50 evenly spaced substeps. If you want it to change the number of substeps based on ease of convergence, use AUTOTS,ON. Third, no precautions require for two or more loads. Last, not sure what you mean by"program proceedure". Are you asking about stepped vs ramped loads? The KBC command controls that.

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[RMANERA]

when I change the TIME value in the analysis, I get different responses between the analyses.

what is the program procedure?


Attached follows my script.

 

[rickfischer51]

Your script does not display for me.

Is this a static analysis? What are your material models? Anything that is time or rate dependent? Creep, visco, etc?

/prep7
block,0,12,0,1,0,.25
et,1,186
esize,.125
vmesh,all
ex,1,29e6
nuxy,1,.3
nsel,s,loc,x,0
d,all,all,0
nsel,s,loc,x,12
f,all,fy,-5
allsel
/solu
nsubst,5,100,2
time,1
solve
/post1
set,last
plnsol,u,y
*get,umax1,plnsol,0,min
/solu
time,150
solve
/post1
set,last
plnsol,u,y
*get,umax150,plnsol,0,min

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[RMANERA]

Attached follows my script again.