Basic Statements 12

Question 1

Cargo carrying ships are designed with optimum transport work as the main design goal

Answer 1

True

Question 2

The classification rulebooks are summaries/descriptions of ships that have survived i.e. design solutions are based primarily on experience and trial and error.

Answer 2

True

Question 3

“Effective breadth” is one way to weight optimize a stiffened panel structure

Answer 3

False - Carrying effective load

Question 4

The main objective with transverse bulkheads is to maintain the shape of the hull girder.

Answer 4

True

Question 5

The design of the hull girder is normally driven by shear force.

Answer 5

False - Driven by bending moments

Question 6

The section modulus of the hull girder determines its longitudinal strength

Answer 6

True

Question 7

The objective with secondary strength elements (stiffeners, beams, longitudinals) is to maintain the shape of the hull girder on the local level.

Answer 7

False

Question 8

Double bottom structures are preferred because they can carry more load compared to single bottom structures.

Answer 8

False - To prevent pollution, if an accident occurs

Question 9

Thick plate thickness inside structures is needed to maintain reasonable shear stresses

Answer 9

True

Question 10

Classification societies always give real load cases in the rulebooks

Answer 10

False - General/typical load cases

Question 11

Important strength criteria to consider in ship design are buckling, yielding and brittle fracture but NOT fatigue

Answer 11

False - Fatigue is an important factor

Question 12

Stiffeners can be used to prevent plate areas from distorting under the influence of shearing loads

Answer 12

True

Question 13

Design loads for trading ships are similar to FPSOs (Float Production Storage and Offloading)

Answer 13

False - they are not similar

Question 14

Structural collapse followed by sinking constitutes approximately one fourth of all ship losses

Answer 14

True

Question 15

Four types of limit states are relevant: SLS, ULS, FLS and ALS

Answer 15

True - 
SLS = Serviceability limit state
ULS = Ultimate limit state
FLS = Fatigue limit state
ALS = Accidental limit state

Question 16

Age-related degradation of material and structure properties does not affect the limit states

Answer 16

False

Question 17

A stiffened panel may collapse in six different types of modes

Answer 17

True

Question 18

Initial imperfection such as welding-induced residual stresses or sideways initial distortion of stiffeners do not affect ULS

Answer 18

False

Question 19

Numerical methods such as the nonlinear FEM give always the true answers to an ULS analysis.

Answer 19

False - Due to mathematical errors, discretization errors and other typical computational errors.

Question 20

Mesh density in a FE model has negligible influence on the ULS

Answer 20

False

Question 21

Reliability-based design and uncertainty analysis are important tools in safety-based analysis using ULS models

Answer 21

True

Question 22

There are international standards how to calculate ULS for ships and offshore structures

Answer 22

False - There are no standards yet

Question 23

There exists clear modeling guidelines how to carry out an ULS analysis by means of FE analysis

Answer 23

False - There are no guidelines yet