This paper presents a review on using friction coefficient in modelling ballistic impact.The are discussed on friction introduced in modelling the impact at different levels: micro (fiber and yarns), meso (woven or unidirectional fabrics) and CPAP Masks macro (layered or equivalent monoblock structures).Recent works simulating the impact projectile - target, done at different levels (micro, meso, macro) pointed out the influence of friction coefficient between bodies in contact.
In all cited references, Set Of Two Wooden Keychains the friction coefficient is kept constant, even if experimental studies proved that it has different values for different sliding speeds, especially for contact metal - polymer as in the impact of aramid fabric armor.