Summary of armor chances in Dom 3?

[Nerfix]

So, what exactly the shields do now? What determines the chance to block, how the blocking can be pierced etc.? Do they contribute to total armor of the unit, and if they do how?

Same for helmets. How much they they contribute to total protection and so on. Does unit with 15 prot helm hit on the head with a Maul take damage, how likely is it to get hit on the head etc,