Parameters Optimization and Energy Absorption Evaluation of the Steel Ball Friction Energy Absorber

Table 7

Predicted energy reflectivity by subtracting the effect of column height and porosity.

Ball column diameter, Dc (mm)	Compressed column height, H’ (mm)	Porosity, λ	Effects of H’	Effects of λ	Energy reflectivity, γ	Predicted energy reflectivity, γ
40	163.83	0.415	—	—	0.215	—
50	161.27	0.366	−0.002	−0.013	0.223	0.230
60	170.32	0.374	0.008	0.002	0.221	0.233
70	174.07	0.393	0.003	0.005	0.210	0.229
80	176.70	0.392	0.002	0.000	0.196	0.212