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yaning
2007-04-12, 22:52
Hello everybody,

First, I would like to say it's a terrific forum and I learned a lot here hope I can contribute to it as well later, not now :(

I am writing vumat for the spring dashpot model (linear elastic+visoplastic &rubber elastic). And then run it for unit element compression. Only the first step runs repeatly. And get the warning deformation speed is larger than wave speed.

The maxdt =1e-5
The default bulk viscosity is used 0.06(linear) and 1.2(quadratic)

Then I remember somewhere in the forum said: Explicit can't use for incompressible model, could it be the reason of the trouble I met? If so, what should I do to make it works.

However, I tried the build in Arruda-boyce model with D=0 using explicit, results are obtained without trouble. Does it mean explicit CAN use incompressible model :? ?


Many Thanks!

yaning

CF
2007-04-13, 10:06
You cannot have fully incompressible material behaviour in ABAQUS/Explicit. As far as I remember, if you specify D1=0 in Explicit, Abaqus will change the value internally such that the poisson's ratio is 0.475.

Cormac

Jorgen
2007-04-24, 05:50
I believe that you can have fully incompressible behavior in ABAQUS explicit for certain element types (such as plane stress).

- Jorgen