;-;asic }iull STFj-:NO'ni 



Consicoi'i-Llc recor^rch or. tho strciifjtl; cf Gpherical cholls his boon 

 ocnductud at tho Kaval Ship Rocoarch ar,a DLvelcp.'ont Concur (KSAiX) . The 

 calvj:iir.ation of thj.s vDrk hns bco the i.iuvoloiir.ei,t. of amly:;is for cho 

 prediction cf the ba:;-ic hull L-trongth bnsel up-jn tho local gacr.itry 

 acro.'^.s a critical arc longth. Tho devc-lc-pir.jnt and vcrific.-itic'n of the 

 ■JSRDC tech?i.iquo has Kon veil docu-.?.ont';G in ti;c open litorature ard vill 

 not bo diccu;3;;od herein. Suffice it to r.ay tl-at r,o;?.i— .'.-rnpirical ocuati on:; 

 './■jre d-3velop'3d for the elastj c^i ^) and i^olasticlP^:} buckling pressure of 

 initially In'porf'ict c-.homr,, by Lakin;^ a(lvant.';);o of. th'j il:-.iibC finding 

 that, since collapse c:' a near perfect spher^-; I3 priniarily a loc-tl pheno- 

 menon, slightly iiripori'ect spheres can be treated by conifidcring the local 

 geometry over a c:-iti;al arc length. 



vhere 



^ is Youngs Modulus uith subseripts s and t ^'onoting secant -yri'] tar.gan 

 ha is average tr.ickness over a critical arc length 



\^i is local radius Lc riidplane of the shell over a critical arc length, 

 a!id fo-vis local radius to outside of the shell over a ori'.ical arc 

 length. 

 The critical arc lengt:(La) based on nominal gcc-etrics is drfin-i a~ 



