In regards to the Cataphracts, theier riders in the Persian and Sassanid dynastys also performed rigourous physical training, which will have made them more able to cope with the heat as a more fit man will be better able to cope with intense heat than a less fit man.

Also what members of the english recreation group, the hoplites, have found is that when it gets damp, through sweat, or through exposure to moisture/water the glues involved in the manufacture of linothorax lose thier efectiveness and it becomes much less rigid and much softer. I dont know how this effects its ability to resist penetration however.

Arrow - radius of 3 mm, energy of 200 joules for 23.5 mm thick bronze or 14.4 mm thick iron.
What???

So what your saying here (or hes saying whatever) is that Ancient period bronze tipped arrows have comparable penetration to modern 5.56mm FMJ?
I doubt it.

A missile penetrates padding or other low density materials [i.e. the linen of the linothorax] by pushing material out of its path.
Thats also how missiles penetrate High density materials, indeed all materials...

The only other way I can think of is rapid pressurisation leading to instant liquidisation as happens with modern ApDS/HEAT tank rounds...

The use of the sword as a primary weapon by Romans and Celts
From what I know of the period and later periods (I know more about middle ages warfare) the main weapon of the Celt like peoples was the spear, as swords were too expensive for the commoner. Is that right or wrong and if wrong please post evidence

But woven textile armour and laminates of cloth and glue display a property known as the limiting velocity, which was described by Jaskowski in 1964. If a textile armour is struck by a projectile travelling faster than the limiting velocity (the speed corresponding to the momentum required to pierce it), the projectile will perforate the armour with virtually no loss of kinetic energy.
How? If it needs that amount of energy to penetrate, that means it will be lost, no matter what, from my knowledge of physics it cant be any other way? Anyone know what this limiting velocity is and how its supposed to achieve the effects it apparently does.