ABSTRACT 



Four cylindrical web-stiffened sandwich models were 

 tested under external hydrostatic pressure. Experimental 

 strains were recorded on both outside and inside shells 

 and compared with theoretical strains computed from 

 existing formula developed at the David Taylor Model Basin. 

 The differences between experimental and theoretical results 

 were within the range of experimental error. 



ADMINISTRATIVE INFORMATION 



This investigation was conducted under the sponsorship of the Bureau 

 of Ships, Code 442, Project No. S-F013 03 02, Task 1956. 



INTRODUCTION 



In recent years, the Navy has shown great interest in the explor- 

 ation of the depths of the ocean by means of deep-diving manned sub- 

 marines. Since the pressure hulls of these submarines are weight critical 

 and often involve the use of thick plates, new types of structures are 

 being investigated to reduce fabrication difficulties and to produce hulls 

 with improved strength-to-weight ratio characteristics. One of these 

 structures is a cylindrical sandwich shell consisting of two concentric 

 cylinders connected by annular webs; this type is illustrated in Figure 1. 



To evaluate the structural strength of a cylindrical sandwich shell, 

 the locations and magnitudes of maximum stresses must be determined. Anal- 

 yses for stress distribution in sandwich shells loaded under external 

 hydrostatic pressure were carried out in References 1 and 2. The maximum 

 stresses occur in the shells at locations next to the webs and midway be- 

 tween adjacent webs. The stresses in these locations are of interest for 

 the purposes of structural design. A graphical analysis for determining 



References are listed on page 13. 



