WINDOWS FOR EXTERNAL OR INTERNAL HYDROSTATIC PRESSURE VESSELS 

 PART II. Flat Acrylic Windows Under Short-Term Pressure Application 



Technical Report R-527 



Y-F015-01 -07-001 



by 



J. D. Stachiw, G. M. Dunn, and K. O. Gray 



ABSTRACT 



Flat, disk-shaped acrylic windows of different thickness-to-diameter ratios 

 have been tested to destruction under short-term hydrostatic loading at room temper- 

 atures, where short-term loading is defined as pressurizing the window hydrostatically 

 on its high-pressure face at a 650-psi/minute rate till failure of the window takes 

 place. Critical pressures and displacements of windows with thickness to effective 

 diameter ratios less than 1.0 have been recorded and plotted. The critical pressures 

 derived from testing flat windows in flanges with 1,5-inch, 3.3-inch, and 4,0-inch 

 openings have been found applicable also to flanges with larger openings, so long as 

 the larger windows are of the same t/Dj and Dq/Dj ratios, where t is thickness of 

 the window, D- is the clear opening in the flange and therefore the effective diam- 

 eter of the window exposed to ambient atmospheric pressure and Dq is overall diameter 

 of the window face exposed to hydrostatic pressure. The performance of flat windows 

 under short-term hydrostatic pressure has been found to be comparable to that of 

 conical windows with included angle equal to, or larger than 90 degrees. 



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The Laboratory invites comment on this report, particularly on the 

 results obtained by those who have applied the information. 



