A Solution to the Inherent List on Nimitz Class Aircraft Carriers

Stress Calculations:
k = coefficient that depends on <strong>the</strong> plate edge conditions,
aspect ratio (AR) of <strong>the</strong> panel, and position of point being considered
a := k • P • — p = pressure based on 1000 psf on sponson shell plating
b = panel width
a = panel length
t = plate thickness
'^imply_supported •= •'^- K;laniped •= -^ ^ ^^'"^^ ^""^ ""o^t conservative
a := 20ft b := 13in based on 13 in separation between stiffeners
P = 6.944—
. 2
in
t := .25in
°max_allowable'= 40,000— lAW with <strong>the</strong> General Specs (Section 100)
in
"'simply_supported •" 'Simply_supported ' '^ ' I T I
^simply_supported ~ 14083—
in
'^clamped • "^clamped ' ^ ' '
^clamped =9389-!^
in
Maximum Allowable Stress for HTS is 40,000 psi. By adding stiffeners at 13 in, <strong>the</strong> stress falls well below that of simply
supported and that of clamped. Simply supported and clamped structural cases are idealizations of structural member support
illustrating zero stiffness and infinite stiffness, nei<strong>the</strong>r of which exists in any real-world structural system. On board ship,
structural systems can be conveniently approximated by one or <strong>the</strong> o<strong>the</strong>r case, but in fact have stiffness between one or <strong>the</strong> o<strong>the</strong>r.
Navy structural analysis is based off clamped ends, <strong>the</strong>refore <strong>the</strong> stress should be well below maximum allowable.
''clamped^^^max.allowabU
114