Learning Forum

[keshav.pathak.raiyam]

I am stuck with writing the mechanical script. I have explained the problem in the Figure. Any idea how to progress to include the time varying and spatial varying load.

 

[dlooman]

There's no way to create a function ahead of time that will automatically update the forces during solution.  The only way to do what you describe is a brute force method.  The duration of the analysis is broken up into many short time steps.  A commands object is executed at the beginning of each time step which interrogates the previous solution and updates the force values with APDL commands.  

[keshav.pathak.raiyam]

Hii Mr. Dlooman

Thank you for your response.

Can you elaborate on it ? Probably with an example script.

I am planning to implement using following algorithm.

[dlooman]

The outline is below.  Unfortunately you probably can't use such a technique without a very good knowledge of the APDL command language.  As mentioned the solution should be broken up into small time steps, dt.  The commands below would be exectuted before each step:

node_numb=node(x,y,z)   ! node_numb is the node closest to the x, y, z location to measure velocity

V_y=VY(node_numb)       ! Retrieve velocity at node

F_dist=Formula                 ! Compute distributed force based on formula                        ! 

nsel,s,loc,,x1,x2                ! Select nodes to apply force to

sf,all,pres,F_dist 

allsel