Exercise 8

NTNUNorwegian University of Science and Technology.

Faculty of Marine Technology

Department of Marine Structures. TMR4205 Buckling and Collapse of StructuresBuckling of stiffened plates according PULS compared with DNV-RP-C201________________________________________________________________________________________Date: March-April 2011 Signature: EKim Distributed Date: 23.03.11 Due Date 01.04.11PROBLEM 1

The stiffened panel analyzed in Exercise 7 shall be analyzed with respect to ultimate strength using PULS. A stiffened panel shall be checked with respect to buckling according to DNV-RP-C201. The panel has the following properties:

t =15 mm

s =650 mm

l =1800 mm

LG =6500 mm

Lp =3250 mm

Long stiffeners HP profile 240x12

It is subjected to the following design stresses

x =150 MPa

y =50 MPa

=25 MPa

External lateral pressure 0.3 MPa

The yield strength is 235 MPa

a) Model the stiffened panel using PULS. The program is available under DNV Software. (UF is calculated by pushing the solve panel button after the input has been generated) Compare with the result obtained with DNV RP-C201. Reduce the axial stress with 90% and calculate the UF. Compare with DNV RP-C201 and comment the result.

For the base case, increase the transverse compressive stress by 100% and calculate the UF. Is the change in UF as expected?

b) For the base case generate the capacity curve in the 1-2 space for p = 0.3 MPa and = 25 MPa. Explain the modest change of the UF in point b) by inspecting the ultimate capacity curve.

c) What is the governing limit-state for the base case?

Check points for limit-states