Trouble with USDFLD

Hi,

I am using a USDFLD to define my fracture criterion through a DAMAGE parameter which is a function of plastic strains.

I will not go too deep into the unnecessary details.

My problem is that, when I am using GETVRM to extract the stresses and strains in the model, I am then establishing a relationship between them as follows:

EPSC=1.2*(0.521/SINH(1.5*SH/SE)

SH is the hydrostatic stress, SE the mises stress and EPSC is a critical parameter. Now, when I tried to save this EPSC as a state variable, Abaqus didnt like it and spewed out an error Illegal Floating Point Errorsignal(8).

Everything seems fine until I add the line,

STATEV(1)=EPSC

Can u kindly advice me in this regard???? This is quite wierd as people are using this line so easily in the example files.

I tried STATEV(1)=ABS(EPSC)

also, FIELD(1)=EPSC

STATEV(1)=FIELD(1), etc...

but to no avail

My guess is that you are running into a floating point error. What if SE==0, or SH==0? Then EPSC might become infinity (INFTY) or non-a-number (NaN).

You probably need to make sure that you dont run into those problems.

- Jorgen