Mattiadalla
Structural
- Aug 24, 2018
- 1
Hello,
first of all I want to thank with all users of this forum for their helpful post and link that I have used lot of times.
Now it's my time to ask a question: I'm doing nonlinear analysis of an earth dam with a new costitutive model, implemented with an umat. I anticipate that it is a very refined material that generates problems of convergence, and I have to do a little comparision between dams behaviour with mohr coulomb-costitutive model and the previous one for my master thesis project.
Before doing seismic analysis, obviously Abaqus have geostatic steps, in order to define stress field inside the dam, but here I have a problem: the analysis provides that the dam is diveded in more layers, so we can simulate the dams construction, and I don't know how can I define initial conditions, because they change step by step. For example:
STEP 1 (geostatic): activate gravity of the first layer
STEP 2 (geostatic): activate gravity of the second layer
STEP 3: ..
and so on. But when I activate the second layer above the first layer at the beginning of step 2 it creates discontinuos stresses between two layers, because to provide stresses in the second layer, umat reads initial conditions of the second layer but it doesn't converge between two layer, cause of different in stress fields. I attach a pic to be clear.
Thank you very much!
Mattia
first of all I want to thank with all users of this forum for their helpful post and link that I have used lot of times.
Now it's my time to ask a question: I'm doing nonlinear analysis of an earth dam with a new costitutive model, implemented with an umat. I anticipate that it is a very refined material that generates problems of convergence, and I have to do a little comparision between dams behaviour with mohr coulomb-costitutive model and the previous one for my master thesis project.
Before doing seismic analysis, obviously Abaqus have geostatic steps, in order to define stress field inside the dam, but here I have a problem: the analysis provides that the dam is diveded in more layers, so we can simulate the dams construction, and I don't know how can I define initial conditions, because they change step by step. For example:
STEP 1 (geostatic): activate gravity of the first layer
STEP 2 (geostatic): activate gravity of the second layer
STEP 3: ..
and so on. But when I activate the second layer above the first layer at the beginning of step 2 it creates discontinuos stresses between two layers, because to provide stresses in the second layer, umat reads initial conditions of the second layer but it doesn't converge between two layer, cause of different in stress fields. I attach a pic to be clear.
Thank you very much!
Mattia