Page 475 - Marine Structural Design

Chapter 25 Reliability of Ship Structures 45 1

Variable Measurements
Description

Elastic modulus, normal variable, Mean=2,06x 1O5~/m2, COV=O.08
Yielding stress, normal variable, Mean=3 1 5MN/m2, COV=0.06

Stiffened panel eccentricity, normal variable, Mean=0.00555m, COV4. 1
Initial center deflection of plating, normal variable, Mean4.5, COV=O. 1
Transition time of corrosion, constant, zi =3 years
Steady corrosion rate of the stiffened panels at deck, normal variable,
Mean=l.4x 1 04m/year, COV=O. 1
Steady corrosion rate of the stiffened panels at side shell and longitudinal
bulkhead, normal variable, Mean=l .25x104 dyear, COV=O.l

Steady corrosion rate of the stiffened panels at outer bottom, normal
variable, Mean=5.4x 1 O-’ dyear, COV=O. 1 1
Steady corrosion rate of the stiffened panels at inner bottom, normal
variable, Mean=l.79x lo4 m/year, COV=O. 16
Steady corrosion rate of comer elements, normal variable, Mean=5.4x
miyear, COV4. 10
Material parameter in Paris-Erdogen equation, normal variable,
Mean4.349~ lo-”, COV=0.206
Material parameter in Paris-Erdogen equation, constant, m=3.07
hitial crack size, normal variable, Mean=l.O~lO-~m
COV=O. 18
Maximum value of still bending moment, Type I extreme variable, Average
arrival period (l/vs ) =1 day
Maximum value of wave-induced bending moment, Type I extreme variable,
Average arrival rate (v, ) =lo8 in a 20 years design life
Environmental severity factor for sagging condition, constant, (ESF), =0.80
Environmental severity factor for hogging condition, constant, (ESF)h =0.80
Model error of predicting ultimate strength, normal variable, Mean=l,
cov=o. 1
Model error of predicting combined total bending moment, normal variable,
Mean=l, COV=O.25(sagging condition)