Unloading step of indentation problem
Unloading step of indentation problem
(OP)
Hello. I am simulating indentation on an elastic-plastic material. It is an axisymmetric contact problem. The indenter is modeled as a rigid cone. The indentation is displacement controlled.
In the loading step, the indenter is driven into the material up to the indentation depth of 1 micron. Then the indenter is withdrawn from the material in the unloading step.
Since the material is plastically deformed in the loading step, the indenter will be detached from the material before the indenter is withdrawn to its original position in the unloading step. But I cannot predict where the indenter will be detached from the material. So, in the input file, I let the indenter be withdrawn to its original position. Hence I waste some computation time on withdraw the indenter after the indenter is detached from the material.
Is there a way to stop the unloading step once the indenter detached from the material where the resistant force is zero?
Thank you very much.
******************************************
*STEP,NLGEOM,AMPLITUDE=RAMP,INC=9000
loading: indent to 1 micron
*STATIC
2E-4,1.0,1.0E-9,0.01
*BOUNDARY
indenter,2,2,-1.0
*END STEP
*STEP,NLGEOM,AMPLITUDE=RAMP,INC=9000
unloading: withdraw to 0.0
*STATIC
2E-4,1.0,1.0E-9,0.01
*BOUNDARY
indenter,2,2,0.0
*END STEP
In the loading step, the indenter is driven into the material up to the indentation depth of 1 micron. Then the indenter is withdrawn from the material in the unloading step.
Since the material is plastically deformed in the loading step, the indenter will be detached from the material before the indenter is withdrawn to its original position in the unloading step. But I cannot predict where the indenter will be detached from the material. So, in the input file, I let the indenter be withdrawn to its original position. Hence I waste some computation time on withdraw the indenter after the indenter is detached from the material.
Is there a way to stop the unloading step once the indenter detached from the material where the resistant force is zero?
Thank you very much.
******************************************
*STEP,NLGEOM,AMPLITUDE=RAMP,INC=9000
loading: indent to 1 micron
*STATIC
2E-4,1.0,1.0E-9,0.01
*BOUNDARY
indenter,2,2,-1.0
*END STEP
*STEP,NLGEOM,AMPLITUDE=RAMP,INC=9000
unloading: withdraw to 0.0
*STATIC
2E-4,1.0,1.0E-9,0.01
*BOUNDARY
indenter,2,2,0.0
*END STEP





RE: Unloading step of indentation problem
For example:
*STEP,NLGEOM,AMPLITUDE=RAMP,INC=9000
unloading: withdraw to 0.0
*STATIC
2E-2,1.0,1.0E-9,0.5
....
*END STEP
RE: Unloading step of indentation problem
As Xerf said, you could leave the maximum increment at default rather than defining it in the data line, i.e;
*STEP,NLGEOM,AMPLITUDE=RAMP,INC=9000
unloading: withdraw to 0.0
*STATIC
2E-2,1.0,1.0E-9
RE: Unloading step of indentation problem
happy easter