Analysis of Stiffened Penstock External Pressure Stability Based on Immune Algorithm and Neural Network

Table 2

Simulating results of the critical external pressure 𝑃_cr.

Critical pressure  (simulation)	𝐿/𝑟
	0.1	0.2	0.3	0.5	0.8
𝑟/𝑡
20	2024.26; (2024.2)	901.87; (901.9)	554.56; (554.5)	299.14; (299.1)	170.36; (170.4)
60	119.16; (119.17)	52.05; (52.14)	31.97; (31.89)	17.43; (17.56)	10.12; (10.18)
100	31.71; (31.57)	13.79; (13.71)	8.50; (8.43)	4.67; (4.71)	2.74; (2.77)
140	13.23; (13.38)	5.75; (5.86)	3.55; (3.47)	1.97; (2.01)	1.16; (1.14)
180	6.88; (6.92)	2.99; (2.87)	1.86; (1.79)	1.03; (1.03)	0.61; (0.67)
260	2.64; (2.57)	1.16; (1.23)	0.72; (0.78)	0.40; 0.37)	0.24; (0.28)
300	1.82; (1.81)	0.79; (0.81)	0.49; (0.51)	0.28; (0.25)	0.16; (0.16)
360	1.13; (1.14)	0.49; (0.45)	0.31; (0.29)	0.17; (0.19)	0.11; (0.15)
400	0.86; (0.81)	0.37; (0.36)	0.24; (0.23)	0.13; (0.11)	0.08; (0.07)