Recently I was playing with some of my friends in gmod, fighting with some sword/knife sweps we found on garrysmod.org… and after a while I realized that the current system source uses for armor is a crock of shite.
So, I devised up a little plan on how we could create an armor system that worked as follows.
The player is equipped with pieces of armor, each with it’s own ability to break, and each with their own custom settings regarding penetration and durability. The pieces of armor themselves are parented to each bone they are required to cover.
(Chest pieces would be broken into 4 pieces for each spine segment if it was chainmail, to simulate flexibility, or perhaps it could be one chainmail model with four bones, each snapped to the corresponding spine segments.)
As the individual pieces of armor are hit, or damaged in however many ways, they change states to compensate for how much damage they’ve taken.
For example, your shoulder pad takes 50 damage and the pad’s body group changes to a dented version.
After the pad takes 100 more damage, the bodygroup would change to a broken version of the shoulder pad, and another piece would fall off, leaving the player exposed in that area.
I was thinking the amount of damage that can be taken differs with the importance of the part the armor covers up.
Images:
As a modeller I can rip models from games and even create my own to an extent. (I’ll most likely rip rom WoW though.)
This could also be adapted for use in bullet proof vests, kevlar helmets, etc.
Consider this one lua coders, this could be epic. 
Also, forgive my shitty paint drawings I’m on a school pc at the moment.