Spall Liner

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NASA test footage of spall generated from a small projectile traveling at 7000 m/s impacting on aluminum plate.

Spall are flakes of a material that are broken off a larger solid body, caused by projectile impact. In anti-tank warfare, spalling through mechanical stress of round impacts on target is an intended effect in ammunition design. The resulting spall is dangerous to crew and equipment, and may result in a partial or complete disablement of a vehicle and/or its crew. Many AFVs are equipped with "spall liners" inside their armor for additional crew protection. (Wikipedia, paraphrased)

Kevlar is a common composite material used in the west as „spall liners“. Kevlar offer less resistance to AP shot compared to Fiberglas but comparable figures for APFSDS and HEAT. Not as good as Steltexolites but lighter at just ¾ of the density, it’s a good solution as a spall liner. The effect of spall is like a ‘small grenade’ going off inside the AFV, with the addition of spall liners this is reduced to a ‘shot gun blast’ [50% reduction in particles and blast cone]. Newer materials like ‘Spectra Shield’ and ‘Dyneema’ achieve the same effect but at 2/3 the weight of Kevlar. Dyneema is of note as being the liner in German AFVs, and has comparable resistance to Fiberglas at 1/3 the density.(Armor Technology, Paul Lakowski)

Gameplay effects

Demonstration of spall effects with (right) and without (left) spall liners.

In Steel Beasts, spall liners are factored into the damage model of the various vehicles that are equipped with them. This is important to keep into consideration, since these vehicles will be harder to kill by design. Spall liners essentially minimize the effects of spall which, in its current representation in the simulation, greatly reduces the chance of indirect crew damages. This means that penetrating hits on vehicles with spall liners will have much lower probabilities of indirect crew damages (direct damage to the actual crew members are unchanged) from spall, as opposed to vehicles that do not have spall liners.

  • Indirect crew damage is defined crew damages suffered from penetrating hits on target where the round does not physically pass through the crew member.
  • Vehicle "kills" in Steel Beasts can occur from several different causes. The most common "kill" occurs when all the crew members of the vehicle are eliminated. Crew members are most commonly eliminated by indirect crew damage from spall effects following a penetrating hit, and through the direct impact on crew members themselves of course. The other way a vehicle "kill" occurs is through a catastrophic fire or ammunition explosion. Since spalling effects are reduced on vehicles with spall liners, more hits are required to disable the other crew members indirectly, or they must be directly disabled. Of course a kill through a catastrophic fire or ammunition explosion makes spall liners irrelevant.

The damage model in Steel Beasts is detailed enough that spall liners are actually present on individual surfaces, meaning that just because a vehicle has spall liners does not mean they are present over every inner surface on the model. On vehicles equipped with spall liners, the typical surfaces that do not have them are roof, hull belly, mantlet, ammo door(s), and inner engine wall(s) (which also act as a crew compartment wall). Of course this is not always the case, but the point here is that vehicle models which are equipped with spall liners do take into account where they are specifically located; they are not simply placed on every surface of the interior.

SB vehicles equipped with spall liners

Current vehicles in Steel Beasts that are equipped with spall liners (see specific vehicle pages for any specific spall liner related notes):

Tanks

Leopard 2A5-DK
Leopardo 2E
Strv 122

PCs

Bushmaster
BMP-2
CV 90/30-FI
CV 90/35-DK
CV 90/40-C
M2A2
M3A2
M113AS4
Pizarro