13 



FIG. 6. A Portion of the Experimental Tube IVa with 16 lobes 

 Around the Circumference. 



The situation is quite different in determining the buckling pressure it- 

 self. Here the experimental values obtained for the individual sizes of models 

 differ very materially from each other. Since the collapsing pressures increase 

 directly as the size of the model, it might be expected that the calculated values 

 should correspond to a limiting case of an infinitely large test body. According 

 to Eq. (6), using the approximation of Fig. 3, the computations show: 



[Translator's Note: Numerous minor numerical errors, probably due to the use 

 of a slide rule, have been corrected by the translator without specific reference 

 in each case. Changes from the original text are indicated * J 



Case (a) oC = 10.47* 

 F*= 1-53 



h= 1 -23 



°- ? Lo Ik 09 +WL (365.6 s * - 2 x 1.53 x 256 + 1.23) x 10~ 6 



309.8* 



309 



y = 0.000264* + 0.000894* = 0.00116 

 Since this value lies above the limit 0.00081, p must be determined from y by 

 Eq. (17). 

 Therefore, 



p = 



0025 x 6200 M - o?ol4T7 = 10 - 5 * kg/cm2 = 10 * 2 * atm ' 



