Parallel Multiscale modeling in ABAQUS using UMAT

Hello everyone,

I am currently in the process of implementing a multiscale modeling approach in ABAQUS/Standard.

Here is what I am doing.

Macroscale ABAQUS model <--> UMAT <--> Python script <--> Microscale ABAQUS model

So basically the microscale model is being called at every macroscale integration point. The UMAT passes the required data to python as command line arguments and the python script returns the stress and tangent modulus in a text file.

The code works when I only use one cpu at the macroscale. When I increase the number of cpus to 2 or more, all the microscale models called in parallel encounter an "unexpected error" in pre.exe. Since we know that when multiple cpus are used, abaqus makes groups of elements to be solved by each cpu, I made separate folders for each element which was then set as the active folder as well as the stratch folder for all microscale calculations for that element. Even then the code does not work.

For cpus=2, I even added a time delay in UMAT for one group of elements just to check whether it was a disk I/O issue. But the solution still crashed during preprocessing of the first element (and later on the second element).

I can't identify the exact issue here.

If anyone has work on similar problems, I could really use some help.

And any suggestion are welcome.

Thanks

M U Siddiqui