The Perimeter Weld option is used when two plates are parallel with each other and welded together around the perimeter edge of one of the plates. Normally these two plates would compress to a mid-plane and you would end up with a gap between the two compressed surfaces. With this option, shell elements will be created between the two surfaces around the perimeter edges of one of the plates. For this option you must first select a thickness to be used for these new shells. It is recommended to use the throat thickness for a fillet weld.
