The HPDE over a very resilient open frame isn't a bad idea , and there are some fine examples of that.
Unfortunatly, never seen one done in any degree of succes in heavyweight.

But don't worry about tear off. HDPE is sliced so easely that the opponent needs to hit a bolt to transfer a lot of force.

Of course, that's taking in account how many bolts of what size and what surface of washer you're suing to keep the HDPE to the frame. Holding 0.25m² 30mm HDPE with 4 M5 bolts won't cut the cheese.