INSTRUMENTATION AND TEST PROCEDURE 



Each model was instrumented with foil-type strain gages 0.063 in. 

 in length. These gages were located on the two shells of each model in 

 areas of critical stress. The middle ring (Ring 5) on each model was in- 

 strumented at locations next to the web and midway between adjacent webs 

 on the 0- and 180-deg orientation. Check points were instrumented at 

 locations midway between the webs on an adjacent ring (Ring 6). Additional 

 gages were also placed on the outside surfaces of the models next to the 

 webs at the 45-, 90-, and 135-deg orientations on Ring 5. Model SER-2 

 was instrumented with additional longitudinal gages covering the area be- 

 tween midbay and the web juncture. After the models were instrumented, 

 the rings were bonded together with the same type of epoxy resin used in 

 the models. 



Figure 2 shows the four models before testing. The models were 

 tested hydrostatically in a pressure tank to obtain elastic strain data. 

 Two pressure runs were made on each model to a pressure of 100 psi, and 

 strains were read at each 10-psi increment. 



TEST RESULTS 



The strain recordings obtained during the second run of each test 

 were used to compute strain sensitivities. These strains were plotted as 

 a function of x/£ (where x is the distance from the web to the center of 

 the strain gage and I is the unsupported length of the bay) and are shown 

 in Figures 3 through 10. The solid line represents theoretical strains 

 computed by utilizing Reference 2. The dotted vertical lines in these 

 figures represent the fillet at the intersection of the web and shell. 



DISCUSSION 



The primary purpose of this investigation was to establish experi- 

 mental verification for the analysis of deformations in web-stiffened sand- 

 wich cylinders. 



In general, excellent agreement was obtained as shown in Figures 3 

 through 10. Data on the longitudinal strain gradient between webs pro- 

 vided by the additional longitudinal gages on SER-2 agreed well with the 

 theoretical values. 



