PSI - Issue 33

Radzeya Zaidi et al. / Procedia Structural Integrity 33 (2021) 1181–1186 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

1183 3

Figure 2. Oil rig pipe, as tested under pressure, [1]

Analytical procedure API 579 The Mode I Stress Intensity Factor for cylinder – surface crack, longitudinal direction – semi-elliptical shape, internal pressure √ , √ The values of and at the crack deepest and surface point are:

( ) ( ) ( ) ( ) ( ) ( )

Deepest point

Surface point

and

are given in [9], as well as other needed quatities:

where values of

( )

√

( ⁄ ⁄ ) ⁄

Newman solution Adjust form by Newman solution for a thin walled shell is given by = [ ( √ ) ( ) ] √ where is the function depending on the geometry (ratio ) ( ) ,

( ) ( ) ( )

( ⁄ ) ( ⁄ ) C =0.85