Page 230 - Marine Structural Design
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206 Part N Ultimate Strength
The equivalent reduced slenderness ratio to be used in the above plasticity correction may then
be expressed as (DNV, CN 30.1, 1995):
1
(1 0.16)
The exponent c depends on the plate aspect ratio. Square plates tend to be more sensitive to
combined loading than long plates, because the two buckling modes coincide for bi-axial
compression. Therefore, a linear interaction is often used for square plates and an elliptic
interaction for long plates. DNV CN 30.1 (1995) propose the following equation for the
buckling strength of the plate under combined loads:
(1 0.17)
10.2.2 Ultimate Strength - Ultimate Limit State
The ultimate strength of the plate may be estimated as (DNV, CN 30.1, 1995):
(10.18)
,
CTuh = - 1.0<&15.0 (1 0.19)
OY
&J5
The Serviceability Limit State (SLS) and Ultimate Limit State (ULS) are compared in Figure
10.7. For very slender plates, the ultimate strength is significantly larger than buckling
strength.
1.2 3
g 1.0 -
'
0.8
-
b"
0 0.6 -
'd
E
V) 0.4 -
B
Vl 0.2 -
0.0 7
0.0 1 .o 2.0 3.0 4.0
Reduced slenderness ratio h
Figure 10.7 Ultimate Strength versus Buckling Strength of Plates.
Balint et a1 (2002) proposed the following equation for ultimate strength of plates under
combined loads:
