[Tomsdad]

Originally Posted by Anthony

That's not actually how flexible armor works. It doesn't do 1/5 as damage, it does 1/5 as injury.

No I know, I was talking about the thresholds:

0-4 Cr or 1-9 cut, imp & pi damage does 0 impact injury

5-9 Cr or 10-19 cut, imp & pi damage does 1 impact injury

10-14 cr or 20-29 cut, imp & pi does 2 impact injury


etc, (are but yes I did use the word damage when referring to impact injury, sorry)

Originally Posted by Anthony

Thus, underlying armor doesn't do anything at all.

Which was why I asked about including the skull, I was assuming you were counting the skull as part of total DR which as you say means it gets ignored. But again as per my second scenario it means any hit of 5+ Cr damage to any skull in any head protection will make the wearer take a knock-down test.

Originally Posted by Anthony

That's to resist penetrating damage.

Well penetrating damage means different things doesn't it, no one actually thinks a mace doing 6 points of damage actually physically pushes past the metal in a DR5 helmet. Basically blunt impact is really just a different factor of Cr injury, since were talking about energy being transmitted through protective layers into the body.

Originally Posted by Anthony

DR is essentially irrelevant against concussion due to rapid head motion; what matters is:

1. Is the helmet held firmly in place, with padding and/or straps, or will your head rattle around inside it?
2. How heavy is the helmet? A heavier helmet moves less quickly.
3. Is the helmet held in place relative to the body? If so, your ability to move your head will be limited or nonexistent, but whatever holds the helmet in place can resist being knocked around as well.

Only a lot of that is based on the helmet and it's DR, hence my earlier point about padding being important not only in general but in that video of the murder blow. Remember helmets and head protection were designed with this in mind, I'd say this is part of the DR of helmet against Cr. So basically your list is actually a series of reasons that a helmet's ability to resist Cr damage is very relevant.

however a couple of other helmet factors vs. concussive force:

1. How well did the padding / layers absorb the energy/movement thus lessening it by the time it reached the head
   
2. There's also how well did the helmet deflect the energy of the blow away from the head.

Again pretty fundamental things in how helmets protect from damage in general, but also factors involved in protecting against concussion (which again in real is not actually fundamentally a different separate things either in terms of protecting from force in general, or something the history of head protection has ignored)




EDIT: Ok looking at the link you gave off your page, a couple of points:

1). You are ignoring the neck (and rest of the body movement) and assuming its an inelastic collision between helmet and head, which it won't be

2). You assuming an all or nothing scenario with the effects of padding in your example. I agree it its unlikely that a TL4 helmet would have enough or good enough padding to completely remove/absorb movement within 22mm, but your assuming that unless it's 100% effective it's 0% effective. You took the best combinations of hammer weights / speeds of you three posted scenarios as well for your exmples

So yes your 2kg hammer @ 10m/s scenario might well require 22mm of padding

but your 1kg @ 15m/s will only need 13mm

I also notice that while you talk about a range or 1-2 as multiplier to take into account different angles etc your examples are all based on 2 so you are assuming the best of all variables. Now as you point out a heavier helmet will move less quickly and that is described in you examples (you're assuming a 2kg helmet) but there are several helms significantly heavier in Load outs (the Gothic Ritter's is almost 3kg when including the visor)

None of these effects need to have huge impact on felt g in order to have huge impact on the chances of concussive hits. As the link in your link points out 100g give approx a 50% chance, but that predictive curve is very steep between 0-100g going by eye a drop to 75g (25% reduction from 100g) drops the chances to just under 20% (over 80% drop in concussion chance from 100g)!

You factor both those effects in plus the others and your losing effect pretty quickly I think