See the following:
"FEM-based single surface contact can be used for SPG parts as long as there is no new surface created due to material failure around self-contact areas. If failure happens everywhere even 'inside' the domain, e.g. in impact and penetration analysis, we currently have two options of self-contact to use:
a. *CONTACT_SPG, ISELF. Support SMP/MPP. More efficient.
b. *SECTION_SOLID_SPG, ISC. Support SMP only. More robust but slower."
I hope this helps.