SCOPE OF INVESTIGATION 



The investigation was divided into two sections: (1 ) the experinnental 

 phase which will be discussed first followed by (2) the analytical phase. 



Experimental Phase 



The objective of the experinnental tests was to accumulate data on 

 full-scale, 90° conical viewports with a range of thickness to minor diameter 

 ratios, t/d. Figure 2 shows a cross section of a typical viewport. The test 

 conditions simulated actual operational conditions as nearly as possible so 

 that the results could be used to provide insight on the type and location of 

 failures occurring during operation. More importantly, the data would serve 

 to test the validity of the analytical results. 



Tests were conducted on six viewports of three sizes as listed in 

 Table 1 . The viewports were all machined from a 4-inch-thick commercial 

 cast sheet of Plexiglas G acrylic plastic. The minor diameters were approxi- 

 mately 4, 6, and 8 inches which gave t/d ratios of 0.92, 0.61 , and 0.45, 

 respectively. 



Table 1. Full-Scale Experimental Viewport Dimensions 



Included 



Angle, a 



(±5') 



Major 



Diameter, D 



(in.) 



Minor 



Diameter, d 



(in.) 



Thickness, t 

 (in.) 



t/d 



90° 0' 



11.863 



4.193 



3.835 



0.915 



90° 0' 



11.854 



4.180 



3.837 



0.916 



90° 0' 



13.969 



6.299 



3.835 



0.610 



90° 0' 



13.950 



6.292 



3.829 



0.608 



90° 0' 



16.013 



8.411 



3.801 



0.453 



90° 0' 



16.025 



8.431 



3.797 



0.451 



