• Registered: 2011-12-21
  • Posts: 2

Topic: Predescribed force

Hi. I want to applie a predescibed force at my structure. I want it to load with 50 kN at every loadstep upp to 3000 kN.

I have tried to do like this:
I go under loading-->load cases-->add. The I chose Forces.

I the go under Joints-->add.
Chose magnitude: 3,0 MN,
coordinate system: Global,
Direction: other, Xg=0,0 Yg=0,0 Zg=-1,0

and then I manually chose the node I want applie the force on.

Then I go under Run-->analysis steps-->
load cases: 1-->
Global solution params: Standard Newton Rhapson-->
Analysis step mult: 1,0-->
number of added load steps: 60

Then I go uner monitoring points -->
type:value at node-->
Item: component 3-->
topological data: Macroelement-->
Macroelement:I chose the macroelement I applied the load at-->
closest to the point: Here I manually put in the coordinates where I applied the load.

The problem is when I run it. I get a message that says the RHS vector is zero. And the force and everything else is also zero.

Any ideas whats wrong?

Quote Post 1

  • dpryl
  • CC software developer
  • Offline
  • Registered: 2007-07-13
  • Posts: 1,107

Re: Predescribed force

Hello Daniel, you definitely have to also define a load case with supports and apply it in the load steps.

If you define the nominal force in your load case and wish to divide it into 60 steps, the step multiplier should be 1/60 in each step.

W.r.t. the monitor, component 3 of what have you selected? External force is what you are interested in when applying force loading (reaction when applying prescribed displacement).

dpryl's Website

Quote Post 2

  • Registered: 2011-12-21
  • Posts: 2

Re: Predescribed force

Thank you for the answer dpryl. Problem solved.

Quote Post 3