layer made of 18 u2033 thick stabilized aluminum foam 3 an anchorage system that consists of 48 dowels each fail in shear if subjected to a shear force of 0 41 mn then 1 the kinetic energy of the aircraft 868 mj 2 volume of saf covering the impacted side 29 1 u00d7 18 523 8 m 3 3 volume of the uncrushed saf following a crash 10 4 u00d7 18 187 2 m 3 4 volume of crushed saf 523 8 u2212 187 2 336 6 m 3 5 energy absorbed in crushing the saf 0 8 mj m 3 u00d7 336 6 m 3 269 mj 6 energy absorbed in moving the outer shield 56 mn u00d7 0 8 u00d7 0 46 m 20 5 mj 7 estimated energy absorbed in collapsing the anchorage system keys plastic deformations of the outer shield and friction 38 5 mj 8 estimated energy absorbed in crushing the aircraft 540 mj 9 total energy absorbed 868 mj it should be noticed that the force generated by the impact is enough to crush the saf and to slide the outer shield impact force 244 mn force required to crush foam 40 u00d7 18 u00d7 0 30 216 mn force required to slide the outer ring 56 mn u00d7 0 15 8 4 mn force.