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-   -   Load step continuation problems - Ansys Mechanical; APDL (https://www.cfd-online.com/Forums/ansys/192662-load-step-continuation-problems-ansys-mechanical-apdl.html)

Lapis1 September 8, 2017 10:21

Load step continuation problems - Ansys Mechanical; APDL
 
I am simulating a load plate using Ansys Mechanical, paired with APDL commands for the entire thing. Due to hardware limitations only one fourth of the entire load plate is being simulated, simulating the rest of the model using symmetry boundary conditions.



Loading the model is done in two steps.

1. Preloading of bolts in the load cells.
2. Applying force on the load plate's top plate, resting above the load cells.



Preloading of bolts is done in two different formats.

1.1 Three distinct f commands simulating constant pretension on relatively unimportant sections. These are applied explicitly during the solution phase of my APDL code, done as seen below.

1.2 Two COMBIN14 spring elements acting on points which are of greater interest. Pretension forces applied by these elements occur automatically once the "solve" line is issued in the solution processor.



The solving part of my APDL code consists of the following.

Code:

! ----------SOLVING #1 - PRETENSION
/solu

        antype,static
!        NLGEOM,ON
        time,1
        autots,on
        nsubst,20,1000,20
        outres,all,all
        neqit,100



! CONSTRAINTS
! Constraints for base
        d,        ...
        d,        ...
        allsel



! Constraints for plate (symmetry)
        d,        ...
        d,        ...
        allsel



! STATIC BOLT PRETENSION
        f,        ...
        f,        ...
        allsel



/solu
        time
        solve





! ----------SOLVING #2 - LOADING TOP PLATE
/solu
        f,        ...

        allsel
        time
        solve



! POST PROC
/post1
        ...
        ...



The intention of the above commands is that the code first applies preloading by itself for both the static preloads and the COMBIN14 elements. The next load step loads the top plate separately, with the previously defined preload kept in place.

The problem with this code is that if I step out of the /solu processor (either to go into the general postproc or into the preprocessor), the second load step will completely ignore the preloading. Instead, the second load step consists of preloading from scratch AND loading the top plate, at the same time, irrespective of what happened during the first step.

Is it possible to continue where the first load step left off, without having to run the simulation again if I were to step into any other processor?


Thank you in advance!


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