Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
parameters affecting ultimate strength of plate and stiffened panels subjected to compressive load are the plate and column slenderness. The plate slenderness is the same for all plates and it is defined as:
tE
b p
p
21 2 yp
The effective width of plate elements ( p as [14]:
(1) ) is calculated (2)
The column’s Euler stress is evaluated considering the whole plating as effective for the calculation the radii of gyration and is given by
E L
22 2
rE L
The column slenderness is defined as y
rE
Radii of gyration is:
r A
I (3)
Table 1 Geometry and material of the stiffened panels Sample
Plate Dim(mm)
FS2-I3 (300×i)×(200×3)×4 FS2-I21 (300×i)×(100+200+100)×4 FS2-I22 (300×i)×(200+200)×4 FS2-I1 (300×i)×200×4 BS2-I3 BS2-I21
(300×i)×(200×3)×4
BS2-I22 (300×i)×(200+200)×4 BS2-I1
(300×i)×(100+200+100)×4 (300×i)×200×4
LS2-I3 (300×i)×(200×3)×4 LS2-I21 (300×i)×(100+200+100)×4 LS2-I22 (300×i)×(200+200)×4 LS2-I1 (300×i)×200×4 US2-I3 US2-I21
(300×i)×(200×3)×4
US2-I22 (300×i)×(200+200)×4 US2-I1
- (4) (5)
The application of the concept of column slenderness raises several difficulties when applied to hybrid panels. For the hybrid panels, the yield stress to be used in Eq. (4) may be the yield stress of the plating, of the stiffener
Y
or the equivalent yield stress. The use of each one leads to completely different results and thus, only the values
of L r
1
AREAS TYPE NUM
Z Y X
MAY 3 2010 22:01:01
and E are presented in Table 2. 1 AREAS TYPE NUM Z Y X
MAY 3 2010 22:01:35
Stiffener Dim(mm)
FS2-I3 I 20×4 FS2-I21 I 20×4 FS2-I22 I 20×4 FS2-I1 I 20×4 BS2-I3
(300×i)×(100+200+100)×4 (300×i)×200×4
SY I 30×8
BS2-I21 I 30×8 BS2-I22 I 30×8 BS2-I1
I 30×8
LS2-I3 L38×19×4 LS2-I21 L38×19×4 LS2-I22 L38×19×4 LS2-I1 L38×19×4
US2-I3 U (40×150×40) ×2 US2-I21 U (40×150×40) ×2 US2-I22 U (40×150×40) ×2 US2-I1 U (40×150×40) ×2
LS US 1.6 p L/r 51.7 E BS2-A3 (a) FS2-A3 1 AREAS TYPE NUM Z Y X
MAY 3 2010 22:02:07
BS2-B3 (b) FS2-B3 1 AREAS TYPE NUM Z Y X
MAY 3 2010 22:02:44
3. NONLINEAR FINITE ELEMENT ANALYSIS
3.1 INTRODUCTION BS2-C3 (c) FS2-C3 BS2-D3 (d) FS2-D3 Figure 4 FE model of FS series for 3 bays
To investigate the influence of different geometries, 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay stiffened panel with different boundary conditions are simulated in the FE analyses. The FE code ‘ANSYS’ is used to assess the ultimate strength of the stiffened panels. The shell 181 element is adopted to model the stiffened panels, which is a four nodes element with six degrees of freedom at each node and can account for linear, large rotation and
26
690 690 690 690 343 343 343 343 296 296 296 296 200 200 200 200
Table 2 Mechanical characteristics of the panels - FS BS
2.2 0.702 13.9 (Mpa) 738 2911 10195 14648 690 SY
©2012: The Royal Institution of Naval Architects
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