Table 3. A comparison between the peak axial force and βL_b eigenvalues.

Pmax	0.9	0.91	0.92	0.93	0.94	0.95	0.96	0.97	0.98	0.99	0.995
βLb	1.48	1.53	1.59	1.66	1.74	1.84	1.95	2.1	2.3	2.65	3
Pmax increment / ×10−5	189	173	155	136	117	97	79	59	40	20	10