A sensitivity study of parameters for secondary splinter generation in Aval
Publish date: 2019-03-04
Report number: FOI-R--4691--SE
Pages: 37
Written in: Swedish
Keywords:
- AVAL
- behind armour debris
- secondary fragments
- shaped charge
- vulnerability assessment
- lethality assessment
Abstract
As part of the work with verification and evaluation of platform-level assessment models, a sensitivity study was performed on the behind armour debris model in Aval. To investigate how the parameters of the model affect a vulnerability assessment of a vehicle, a series of simulations was performed where the parameters number of debris fragments and debris cone angle were varied. The other fragment parameters were dependent on the number of fragments by assuming a constant total mass for all fragments. Thus, when the number of fragments increased, the individual fragment mass decreased to keep the total mass of fragments constant. The penetration capacity and effective diameter of the fragments were directly dependent on the individual fragment's mass and shape, and therefore varied with the number of fragments in the simulation. The events studied were loss of mobility, loss of main armament and incapacitation of at least three out of seven embarked soldiers. The results showed that the amount of fragments affect the result to a higher degree than the fragments' individual penetration capacity. A larger opening angle of the cone of fragments correlated in most cases with an increased probability of incapacitation of the vehicle. This was interpreted as that the number of fragment hits and the number of components being hit were more important factors for the incapacitation of the vehicle, than the size of the fragments. The small fragments probably primarily have an effect by injuring the crew inside the vehicle. The crew are an integral part of the mobility and firing ability. Apart from penetration damage, which was the primary effect causing the vehicle to stop functioning, pressure from exploding fuel tanks and ammunition was a large contributing factor to eliminating the vehicle. Areas of further interest and development when it comes to improving the model are the effect of many small fragments in soldier targets wearing uniform, refined pressure criteria for soldiers and other components, the model for generating pressure from fuel fire and giving the secondary fragments mass and velocity that can be varied.