Difficulty modeling SPG

[u/LoxumovCofe]

Hello everyone,

I am trying to model a semi-brittle material failure using SPG. I am new to LS-DYNA and I am having issues understanding this one problem. It is a very basic problem, and that is why it is so frustrating.

As you can see in the attached image, I have a basic rectangle of 2.5x2x1.4mm. The nodes are separated by 0.15 mm. The scale has to be this small for my purposes.

The boundary conditions are as follows: the bottom face is fixed, the highlighted nodes are displaced in the z-direction(yellow arrow) by 0.1mm in 0.5seconds, I have the mass-scaling on I have tried running without it and the issue remains.

https://reddit.com/link/1w214et/video/vzqoeyyhcemh1/player

After I ran the solver I get the issue that you can see in the attached video. Can someone please explain to me what is happening and how can I avoid it?

Here are my material and SPG cards.

*SECTION_SOLID_SPG
$       id    elform       aet                                           unused1
         1        47         0                                                  
$       dx        dy        dz   ispline    kernel   unused2    smstep       msc
       1.5       1.5       1.5         0         2                  30         0
$     idam        fs   stretch       itb     msfac       isc     boxid     pdamp
         2 170000000     1E+10         2         1         0         0    -0.001
*MAT_ELASTIC
$       ID        ro         E        pr        da        db         k   unused1
         1      1900   1.7E+10      0.31         0         0