Re: Repeated Drop

No problem Kok,

Explicit to Explicit importing is not (yet?) possible.
Implicit to explicit (and vice versa) is possible. I am currently 
working with drop simulations of aluminum beverage cans (soda cans).  
I am importing a 'pre-pressurized' can shell from standard to 
explicit. The imported shell retains all deformation and stress 
properties from the static run.   I have also gone from explicit 
(with damage), to implicit (to settle, and reset), and back to 
explicit (second drop) with no major problems (aside from mesh 
issues, adaptive meshing for shells would be great). I believe that 
all of the pertinent information comes along with the model as it is 
imported to the next application. 
Also, please check element type compatibility between standard and 
explicit.
As for how the strains would be interpreted, I think that depends on 
the 'Update' and 'State' parameters of the *Import option. The 
correct combination of these parameter settings should allow the 
elemental strain information to pass to the next analysis.

Are you dropping a closed container? You mentioned using membrane 
elements, are these internal hydrostatic elements or are they part of 
the main structure? I am very curious to hear/read what others are 
doing in this area.  

Regards,

Dan Dailey



--- In ABAQUS@xxxxxxxxxxxxxxx, CheeKuang Kok <cheekuang_kok@xxxx> 
wrote:
> 
> Thans Dan.
> I have read the manual about initial conditions and import. As far 
as I know, an explicit analysis cannot be transferred to anaother 
explicit analysis. Implicit to explicit or vice versa is possible. 
Please correct me if I am wrong.
> My current strategy is to output the deformed state (output 
stresses, and displacements, plastic strain) into .fil, and read them 
back using subroutine HKSMAIN. I will used the displacements as my 
coord for the nodes, and use *INITIAL CONDITION, TYPE=STRESS and 
*INITIAL CONDITION, TYPE=HARDENING (for plastic strain) to define 
initial conditions of the second or subsequent analyses. I will have 
to run a dummy step to ensure equilibrium of stresses in my second 
and subsequent analyses.
> To be more accurate, I wonder:
> 1) Whether this strategy is feasible? Is there a better way.
> 2) How would the elements interpret the strains? I have failure 
strain criterion. How do I deal with the residual strain in the 
second and subsequent analysis?
> 3) Most importantly, I have shells, and membranes too. How about 
all those section forces and moments?
> If you are out there and see this message, please kindly help out. 
> Thanks
> Kok
> 
> Dan <daileyd@xxxx> wrote:
> 
> 
> Read about using *import and *initial conditions in the manuals. I 
> believe that the deformed state is read in via the odb file not the 
> dat file.  You may need to run through a 'dummy' implicit job 
before 
> importing the results of an explicit job into another. Please read 
> sect 7.7.2 in the user Abaqus Analysis User's Manual.
> 
> Dan Dailey
> 
> 
> --- In ABAQUS@xxxxxxxxxxxxxxx, "cheekuangkok" <cheekuangkok@xxxx> 
> wrote:
> > 
> > 
> > Hi Abaqus users,
> >    I would like to simulate the drop of an object to a rigid 
floor, 
> > let it bounce back a bit, stop the analysis. With this deformed 
> > state after the drop, I will bring the object back to its 
original 
> > initial velocity (as in the first analysis), and drop the object 
> > again.
> >    What is the best way to simulate this repeated drop? I am 
using 
> > ABAQUS/explicit (there is no dat file produced). How do I read in 
> > the deformed state into the new analysis? Thanks!
> > 
> > Chee Kuang Kok
> > Graduate student
> > Michigan State University
> 
> 
> 
> 
> 
> 
> 
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