When were spall-liners introduced?

[riggerrob]

When were fabric spall-liners introduced for AFVs?

 

[_Del_]

Early 80's was when it began picking up steam as a concept. M113A3's got it in the mid-80's as part of a survivability upgrade, as I recall. Tanks got them rather earlier.

 

[Rickshaw]

I believe it was in the early 1980s when various fibre armour systems came into general use. It works on the theory that rounds that penetrate the vehicle's hull then encounter a spall liner made of fibre armour which reduces their penetration. Effectively, it is like adding armour on the outside of an AFV's hull but doing it inside.

 

[TomS]

I believe it was in the early 1980s when various fibre armour systems came into general use. It works on the theory that rounds that penetrate the vehicle's hull then encounter a spall liner made of fibre armour which reduces their penetration. Effectively, it is like adding armour on the outside of an AFV's hull but doing it inside.

As the name implies, spall liners aren't primarily about stopping penetrating projectiles, but fragments knocked off the inside surface of the armor (spalling) by hard but not necessarily penetrating impacts (say from HESH or HE). They also help limit secondary fragmentation from disintegrating penetrators and armor in penetrating hits.

 

[iverson]

As the name implies, spall liners aren't primarily about stopping penetrating projectiles, but fragments knocked off the inside surface of the armor (spalling) by hard but not necessarily penetrating impacts (say from HESH or HE).

While this is not my area, I seem to recall reading about this.

HESH (high explosive squash head) munitions are designed to defeat homogeneous steel armor. A plastic explosive warhead flattens against the outer armor, explodes, and causes a shock wave to resonate between the inner and outer surfaces of the armor. The armor eventually fails on the inner surface, sending large scabs of relatively low-velocity metal to smash everything inside the armor shell. Spall liners protect the crew against this material.

However, HESH is not effective against against heterogenious armor, such as spaced armor or laminates. HEAT (high explosive antitank, or shaped charge) warheads are at least somewhat effective and are thus now more commonly used. These munitions focus blast energy on a specially shaped copper liner, projecting a long, thin, high velocity jet of vaporized metal that can penetrate large thicknesses of armor. Spall liners can't stop the jets. But they can catch any fragments that break off the inside layer of the armor when the jet penetrates. The jet is relatively light, so anything that reduces the number of heavier fragments presumably limits damage.

In much the same way, spall liners also limit fragments when solid shot (APDS or APFSDS) penetrates armor. Since the shot is heavier, though, I imagine that fragmentation is more extensive and spall liners are proportionately less effective.

 

[lastdingo]

HESH breaks off way too much on the inside for a spall liner to stop. It can even punch entire big holes in plates.
Spall liners work only against shaped charges well by reducing the cone angle of spalling inside.


The predecessor of spall liners was to use a ductile backplate in layered armour (such as in T-72 glacis IIRC) or to face harden on the outside only (many German tanks in WW2, for example). All-fibreglass armour was tested and promised littles spalling without a liner, but glass is still nasty in case of penetration.

I've also seen some Russian or Ukrainian suit for tank crews that offered nearly full-body frag protection (similar performance to steel helmet or early kevlar flak vests, not NIJ level 2-like as many of today's basic protective vests). There are also frag-protecting tanker helmets.