Implementing previous step output as input in the using Abaqus 2

[moonmoon2007]

Dear Abaqus Users,
Help is needed please on how we can get the output displacement of some certain nodes and implement them in a formula to become forces (from each node results); and add this forces into their corresponding nodes in the following new step, for multiple steps.
Thank you for your helping answers of any approaches and they are really appreciated .
Thanks

 

[mrgoldthorpe]

You could do this by means of common blocks in Fortran User Subroutines. For example you could user UVARM to set up parameters on the common block at the end of each increment, then DLOAD uses those parameters to load the model in subsequent steps or even subsequent increments.

 

[moonmoon2007]

Thank you mrgoldthorpe so much for your fast reply. I am new in using Abaqus by writing input file rather than use CAE only. If I would like to follow your approach, what is the pathway to achieve that? I already started on reading the (getting started manual, keyword edition); what other topics I should learn to be able to do this. I am sorry for asking a question might be easy but really I don’t know the right way to approach your idea. I need some steps and I will read on them to be able to write the input file.
Thank you for sharing your knowledge.

 

[mrgoldthorpe]

Read the manuals on User Subroutines. As I said, I suggest you use perhaps SUBROUTINE UVARM to pick up output variables such as displacements that you wish to monitor. To do this you need to set up at least one user variable (*USER OUTPUT VARIABLES in the input file). As I said above, you can either use a Fortran common block to transfer information to establish the loads, or you can use one or all of the User Output Variables(s) to do this.

There are several User Subroutines for applying displacements and tractions. These are: DISP, DLOAD, UTRACLOAD. (However, I'm afraid isn't one for concentrated loads at nodes, the equivalent of CLOAD. Can you apply your loads via a distributed load - pressure - moonmoon?) Anyway, the principle is that you use either your calculated User Variables from say the previous load increment, or the variables you stored on a common block, to set up the loads you need.

If you still aren't sure and ask another questions, can you perhaps state more precisely what you wish to do. Other contributors may be able to help you more.

 

[moonmoon2007]

Thank you for your generous suggestions. It is a static structural model imposed against rigid flat surface with several steps. The contact nodes (the open ones) from the contact surface need to applied with attraction force depends on the distance between each node (which still open from the contact surface) and the flat rigid surface at each step. Right now I started with a simple axisymmetric (like a hemisphere only with rigid surface) to understand the how it can be done with Abaqus. Thanks again