# Members's Marine

Description
cw
Categories
Published

View again

All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Related Documents
Share
Transcript
QUESTION For X60 steel pipe, plot the maximum water depth depth(m) versus R/t (7.5 < R/t < 20) for various f  0 (f  0 = 1, 2 and 3  )  SOLUTION The effects of initial ovality, from DnV 2000 rules gives us the following equation; 22 ()()2 ..................(1) c ecr c y ecr y c o  R p p p p p p p f  t       Where;   is the collapse pressure   is the elastic critical pressure   is the circumferential yield pressure     is ovality If we expand the brackets in equation (1), we obtain the following;                               If we collect like terms,                               ...............(2) The above equation is in the form of the general cubic equation;        ......................................(3) Equations (2) and (3) are similar, so we have the following relationships; a = -   b = -                c =        In solving our cubic equation, we use Cardano ’s  method of solving cubics. The discriminant   of the cubic equation is found to be negative and the   is a complex number, therefore all roots of the cubic equation are real and different.   Thus, the roots of the equation are;                       Where          (√   )             The roots of our cubic equation are given by;                              The circumferential yield pressure, .  y y t  p R         The elastic critical pressure,   32 41where:E=young's modulus (210Gpa)=poisson ratio for steel(0.30) ecr   E t  p R           The collapse pressure, .. c  p g h        TABLES OF VALUE ParametersUnit Steel Grade - X60 SMYS, σ  MPa 414R/t - 7.5 - 20Ovality,  f   0  - 0.01 - 0.03Acceleration due to gravity, g m/s 2 9.81 Density of sea water, ρ  Kg/m 3 1025

Jul 23, 2017

#### 7

Jul 23, 2017
Search
Similar documents

View more...
Tags

Related Search