I. INTRODUCTION 



The work described herein covers the experimental stress analysis 

 of a 0. 286 scale, hemispherical model which was subjected to loads of 

 uniform external pressures. The model simulated the hull of an oceano- 

 graphic vessel being designed and fabricated by the General Mills Company 

 for the Woods Hole Oceanographic Institution. The full scale design has 

 been referred to as "Alvin' by the above two organizations. The results 

 from the experimental stress analysis of the scaled model can be trans- 

 formed by structural similitude to verify the adequacy of the full scale 

 design. 



Tests were conducted with two configurations of the model, the 

 cross sections of which are given in Figure 1. Both model configurations 

 had a plexiglass window. Dr. J. W. Mavor* and Mr. F. Pons** are shown 

 in Figure 2 checking the thickness variation of Configuration A by utilizing 

 a granite flat (flat within 0. 0001") and a mechanical displacement type of 

 gage. All dimensions were found to be well within the specified tolerances 

 given in Figure 1. 



After the test with the pristine configuration was completed, the 

 port was machined to the larger diameter, as shown in Figure 1, and a 



* Engineer, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 

 ** Machinist, Machine Shop, Southwest Research Institute 



