PSI - Issue 52

A.D. Cummings et al. / Procedia Structural Integrity 52 (2024) 762–784

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A. Cummings / Structural Integrity Procedia 00 (2023) 000–000

(a)

(b)

Fig. 5. Base drop (height 1.2m) - Maximum principal stress contour plots (a) Base centre (b) Base internal radius

(2016) which separate peak stresses from primary and secondary stresses. The equations provide a statically equivalent structural stress which was originally developed to assess fatigue of welded joints, see Dong (2001):-

1 t

t

σ x ( x ) dx

(13)

σ m =

0

And:

6 t 2

x dx

σ x

t

t 2 −

(14)

σ b =

0

The resulting stresses are σ m = 101MPa and σ b = 277 MPa and are used to calculate σ ref andL r . As a sensitivity study, these stress components have also been used to calculate K I , although the basis for their use, which excludes a proportion of the peak stress in the calculation of K I , is not suggested in either BS7910 (2019) or ASME FFS 1 / API579-1 (2016). To account for the peak stress in the calculation of K I , linearization across the flaw(s) has been performed fol lowing guidance in BS7910 (2019). Fig. 7b shows the stress linearization across the flaw which results in very large values of negative membrane stress and positive bending stress. Due to superposition these values result in reasonable