591 



As many as eight Modugno gauges were placed in a large static 

 pressure chamber and subjected to desired pressures indicated on a 

 Bourdon gauge. Resulting deformations were measured to .001 in. with 

 a micrometer depth gauge. Diaphragm thicknesses were measured before 

 and after deformation to .005 in. 



The reproducibility of the experiment was investigated at pressures 

 of 5000 lbs/in.^ and 10,000 lbs/in. 2. The variation of damage with diaphragm 

 thickness was studied for several pressures. Also, static depressions 

 were used to calculate the tensile strength of the diaphragm. 



Typical results of consistency experiments listed in Table XXVI 

 show that damages for disks cut from a single diaphragm of uniform 

 thickness could be reproduced to somewhat better than 2%. (Each set of 

 four was deformed simultaneously.) 



Table XXVI - Static deformations 



In order to get an empirical correction for thickness variations, 

 a number of disks were deformed at pressures of l|-600, 5OOO, 6OOO, 7OOO, 

 8000, and 9000 lbs/in? The results are plotted in Figure 32. 



The tensile strength of a thin diaphragm may be calculated by means 

 of the theoretically derived f ormula3V : 



T.S. = h. =|^-iiL 

 2t V ^^^ 



i3l) 



where R is the radius of curvatiore, p the static pressure, t the thickness 

 of the~diaphragm, r the radius of the undamaged diaphragm, and x the 

 maximum deformation. 



31/ A. N. Gleyzal, Taylor Model Basin, U. S. Navy Report No. 490. Sept 19^2. 



