FEMAP SUBSTEP/MULTISTEP/Multiple loadcases for same BCs 1

[Xprivate]

Hi All , i am trying to analyse a model for two different loadcases with same constraint conditions. The first loadcase will cause a deflection and with the deflection as initial point i want to apply a point load and track the various loads.

To better explain, imagine a rectangular plate fixed on the edges,
i want to apply two load cases for same fixed constraints. 1)pressure on the plate 2) a point load locally on the plate.
so i want to run a non linear case where i first run a SOL with pressure case and with that as initial start point for point load (second loadcase) on the plate. But for the second case i want intermediate results where i want to track the load at which the plate fails. The point load is unknown but the pressure is known. Can someone help me how this can be done on FEMAP?

THanks in advance

 

[TG_eng]

What solver are you trying to use?

SOL106​

SOL401/402​

Also what do you mean by the point load is unknown?

 

[Xprivate]

lets say the point load is 100 pounds but i want output for every 10% of loads , i.e every 10lbs . i also want results at 10lbs, 20lbs,30lbs upto 100lbs because i do not know the failure load and 100 lbs is just a random load i am using to test .


thanks

 

[rb1957]

linear analysis ? why non-linear ?

"surely" superposition will do it for you (and, yes, I know your case is more complicated than your example).

but it sounds like you have one case you need to apply (like pressure in your example), so this'll apply loads, use some capacity, result in some MSs.
then you have a second loadcase that you can vary for failure. so apply this 2nd case (in isolation) and get a second set of MSs. Combine (not sum, [1]) with previous set, locate the critical MS, then go back to the first case to see how much proportion of the second you can apply for MS = 0.

This is where the good olde RF comes in ... I think it's something like ... MScombined = ((1/(MS1+1) +1/(MS2+1))^-1 -1,
RFcombined = (1/RF1+1/RF2)^-1 ... I think (without much thought)

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[ThomasH]

i want to apply two load cases for same fixed constraints. 1)pressure on the plate 2) a point load locally on the plate.
so i want to run a non linear case where i first run a SOL with pressure case and with that as initial start point for point load (second loadcase) on the plate. But for the second case i want intermediate results where i want to track the load at which the plate fails. The point load is unknown but the pressure is known. Can someone help me how this can be done on FEMAP?

Use a nonlinear static solution, SOL106.
First load case includes the pressure load.
Second load case includes the pressure load and the point load. Request 10 increments for the load and all intermediate resuls.

That will gove you resulte for pressure only and then for 10/20/30/40/50/60/70/80/90/100% point load. But you have to assume a value for the point load to start with.

You say that you are searching för a failure in the plate. I assume tahat there is some type on non-linear material involved because otherwise I can't se the reason for a nonlinear approach.