Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
Some studies have already been performed for stiffened panels. A series of nonlinear finite element method computations were carried out for two full bays (1+1 bays) model with various parameters of influence to investigate the ultimate strength of
stiffened panels
representative of ship hulls [9]. Zhang & Khan [10] and Fujikubo [11] analysed the ultimate strength of plates using non-linear FE software by one full bay plus two half bays (1/2+1+1/2 bays) model.
Gordo and Guedes Soares [12] ultra-high strength steels (H690) conducted an
experimental study that was aimed at comparing a new shape of U stiffeners to be used in very fast ships made of
with panels
reinforced by the usual shapes of stiffeners. The base geometry is the one used on the tests of Gordo and Guedes Soares [12, 13].
This study aims at studying different configurations of the stiffened panels than the ones in those tests [12], but with the same dimensions of plate fields and stiffeners, in order
to decide if there would configurations be more robust that would be less sensitive to the
imprecision in boundary conditions that can exist in experimental set ups. The ultimate strength of stiffened panels under axial compression until collapse and beyond are calculated for 120 configurations with different boundary
conditions and model
Figure 1 Geometry of 1/2+1+1/2 (L1=0.5L2) and 3 bays (L1=L2)
geometries. These
stiffened panel models include 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay. In the longitudinal direction, the 3 bays model consists of three full bays, the 1/2+1+1/2 bays model consists of one full bay plus two half bays, the 1+1 bays model consists of two full bays, the 1 bay model consists of one full bay. The plate is always high strength steel (S690) but the stiffeners are made of mild or high tensile steel for bar stiffeners and mild steel for ‘L’ and ‘U’ stiffeners.
2. DESCRIPTION OF THE MODELS FOR THE ANALYSIS
Figures 1 - 3 show the geometry of the different stiffened panels. Four series of stiffeners are carried out using different types of steel as follows:
FS series - fully S690 structure: S690 on plating and bar stiffeners.
BS series - hybrid bar structure: S690 on plating and mild steel on bar stiffeners.
LS series - hybrid L structure: S690 on plating and mild steel on L stiffeners.
US series - hybrid U structure: S690 on plating and mild steel on U stiffeners.
Figure 3 Geometry of 1 bay
Table 1 shows the geometry and material of the stiffened panels, in which the value of I and i are as following: i=1 when I=A, i=2 when I=B, i=3 when I=C, i=4 when I=D, i=5 when I=E. The dimension of the transverse frames is L bar stiffener 50 ×20×6 mm and the thickness of the plates is 4 mm. The A-E means different number of the stiffeners in Figure 1-3, and the FE model of the FS series for three bays is shown in Figure 4. The principal
Figure 2 Geometry of 1+1 bays
A-68
©2012: The Royal Institution of Naval Architects
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62