assigning velocity Initial conditions
assigning velocity Initial conditions
(OP)
Hi,
I have a question on regard of initial rotating velocity to specify before the STEP keyword. Abaqus supports both:
INITIAL CONDITIONS, TYPE=ROTATING VELOCITY,
and
INITIAL CONDITIONS, TYPE=VELOCITY.
For my problem, what's the difference between using these two options? If for the second one, can I specify the rotating velocity? How do I specify the rotating axis?
Thanks very much!
Sean
I have a question on regard of initial rotating velocity to specify before the STEP keyword. Abaqus supports both:
INITIAL CONDITIONS, TYPE=ROTATING VELOCITY,
and
INITIAL CONDITIONS, TYPE=VELOCITY.
For my problem, what's the difference between using these two options? If for the second one, can I specify the rotating velocity? How do I specify the rotating axis?
Thanks very much!
Sean





RE: assigning velocity Initial conditions
The definition of velocity in the case of using INITIAL CONDITIONS, TYPE=VELOCITY is related to the nodal degrees of freedom. The allowed degrees of freedom depends on the type of element you use. Some might have only translational degree of freedom. Such that to have an equivalent to a rotating velocity field (defined by INITIAL CONDITIONS,TYPE=ROTATING VELOCITY ) you should prescribe different velocity vectors at each node.
You can find the exact syntax in "ABAQUS Keywords Reference Manual"
RE: assigning velocity Initial conditions
Sean
RE: assigning velocity Initial conditions
If you use INITIAL CONDITIONS, TYPE=VELOCITY then you'll have to define for each node the velocity vector such that
the resulting velocity field to correspond to a rotational motion with uniform rotating velocity( i.e. you have to compute by yourself the velocities vectors V|node=OMEGA x position vector (from rotation axis to node) , then you have to decompose each nodal velocity vector in components corresponding to the traslational degree of freedom , namely U1,U2 (and U3 for 3D problems)).
I don't think this is the common way for doing this task.
RE: assigning velocity Initial conditions
The memory leak -- the preprocessor failed while failing to request additional memory than maximally allowed on the computer.
RE: assigning velocity Initial conditions
A memory leak is caused by poor programming, where a subroutine grabs memory when called by the main program segment and then fails to release this memory when the subroutine exits, if this subroutine is called many tiimes then all available memory resources are rapidly devoured! This is not your problem, your model simply requires more resources than are available for it to run.
I very much doubt if anything as bad as a memory leak will find it's way into a released version of Abaqus!
RE: assigning velocity Initial conditions
My Unix machine is with Solaris 9 OS with 6G RAM. However, I was told that the maximum RAM addressible is 2G, and if I need to address a larger space, need to go back to Solaris 8. Is this true? Thanks!
RE: assigning velocity Initial conditions
I wouldn't down grade your OS, I doubt if that would fix your problem. Why are you still using version 6.3 when 6.5 is now the current version? Have you tried forwarding your problem to Abaqus support?