Table 2.

Maximum stress values of sensors under different impact energy levels.

h(m)	E(kJ)	A-2 (${\mathit{\sigma }}_{\mathit{m}\mathit{a}\mathit{x}}$/MPa)			A-3 (${\mathit{\sigma }}_{\mathit{m}\mathit{a}\mathit{x}}$/MPa)			A-4 (${\mathit{\sigma }}_{\mathit{m}\mathit{a}\mathit{x}}$/MPa)
		S-1 (Z)	S-2 (Y)	S-3 (X)	S-1 (Z)	S-2 (Y)	S-3 (X)	S-1 (Z)	S-2 (Y)	S-3 (X)
1.0	3.32	25.41	4.01	6.65	30.97	7.62	8.28	40.72	6.01	7.22
1.5	4.98	38.56	4.00	7.67	44.45	8.5	9.74	49.21	8.02	8.52
2.0	6.64	38.02	5.16	8.27	43.67	8.95	10.17	50.29	8.23	9.75
2.5	8.31	39.60	5.90	7.57	45.15	9.4	11.29	49.23	9.12	10.02
3.0	9.97	39.75	7.54	8.28	44.09	10.86	11.92	51.36	8.96	10.95
3.5	11.63	41.93	7.21	7.60	44.12	11.51	11.25	49.36	11.25	9.53
4.0	13.29	41.17	7.06	7.14	45.67	11.14	12.18	42.67	10.63	11.23

Note: The letter A indicates the concrete filled steel tubular column, the number following A indicates the wall thickness in mm, h indicates the impact height, and E indicates the impact energy.