I logged onto exp to test things out, and decided to f11 to start fresh. I crouched next to a small pine tree, dropped all of my gear, including a plate carrier on the ground, dropped a grenade at my feet, and it blew up but did not damage me. I tried it with both variants of the frag grenade. I don't know if it was the collision with the tree, or the collision with the gear, maybe the plate carrier, that blocked the explosion.