Moderately Long Cylinders . The expressions to predict implosion 

 pressure for moderately long cylinders are developed as follows. 

 Equations 9 and 10 are substituted into Equation 7 to yield: 



1090 , ^ 

 a. I D 



itn _ \ o 



t \^-' 





The stress level at implosion, a. /f ' , is calculated by knowing the 

 geometry of the cylinder structure. The following conditions determine 

 the next step: 



(a) If a. /f > 1.0, thick- wall analysis is used to predict 



mi c ' •' ^ 



implosion. Equation 3 



(b) If 0.52 < a. /f < 1.0, then n is calculated by Equa- 

 tion 10 



(c) If a. /f < 0.52, then n = 1-0 



mi c ' ' 



If steps (b) or (c) control, the following expression, which was 

 developed by substituting Equations 7 and 9 into Equation 1, predicts 

 the implosion pressure. 



■t ^2-5 

 1320 n f 



c \ D 



P = • ^"-^^ — — (■12') 



im L/D ^ ■' 



A design chart approach is given in Figure 3. Enter the chart 



with the structure's L/D and t/D ratio to determine the P. /f ratio. 



o o im c 



The structure is assumed to have a simple- support end condition. 



18 



