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

Table 7

The calculation results of stiffening ring stability.

Shell-thickness; (mm)	Ring-thickness; (mm)	Ring plate-high; (mm)	Stiffening ring instability
			Instability pressure (MPa)	𝐾
20	20	300	2.380	2.98
22	22	300	2.685	3.36
25	25	300	3.159	3.95
27	27	300	3.468	4.36
29	27	300	3.823	4.78