Stress intensity factors for a wide range of long-deep semi-elliptical surface cracks, partly through-wall cracks and fully through-wall cracks in tubular members

Stress intensity factors for high aspect ratio semi-elliptical internal surface cracks in pipes

“…2, one face (cracked) of the brick element containing nodes 3, 5, and 8 is compressed to a line so that nodes 3, 5 and 8 become one single node. This is the same as for nodes (11,12) and (15,17,20). Because the nodes on the compressed face can each "freely" move the singularity induced stress field due to such "free" movement may follow rules different to 1= ffiffi ffi r p .…”

“…Fett's method was dedicated to 2-dimensional surface cracks with limited application to a variety of loading distributions. Kou and Burdekin [17] used finite element method to calculate stress intensity factors with high aspect ratio up to 2.0 for circumferential semi-elliptical surface cracks but not longitudinal cracks. It is the longitudinal cracks that are most likely to cause pipe collapse.…”

Surface Crack Growth in Offshore Metallic Pipes under Cyclic Loads: A Literature Review

“…The growth behaviour of shallow surface cracks (a/c ≤ 0.5) was studied, where it was concluded that shallow cracks grew more rapidly in the depth direction than in the surface direction; correspondingly, the largest SIF was at the deepest point of the surface crack, while for high aspect ratio surface cracks (a/c > 1.0), due to corrosion attacks, the maximum SIF might occur at different positions along the crack front. Deep surface crack growth (a/t > 0.8) in pipes subjected to tension was studied [34], which indicated that the maximum and minimum SIF were always at the deepest point and the surface point, respectively. The effects of the ratio between the internal radius and the pipe thickness (R t /t) were studied as well [36], which showed that the R t /t ratio was an independent coefficient to the a/c and a/t ratio of SIF evaluation on surface cracks in metallic pipes.…”

“…Among the literature in regard to the surface crack growth in pipes, experimental studies [12,[20][21][22][23][24][25][26], as an indispensable and important component, have been conducted on surface cracked pipes for the purpose of understanding the mechanism of surface crack growth, calibrating and validating related numerical and analytical evaluation methods. The majority of the studies focused on numerical approaches, mostly by means of the FE method [12,[27][28][29][30][31][32][33][34][35][36][37][38]. Analytical approaches [12,25,30], which are of significant value to guide practitioners in practical situations, are relatively insufficient.…”

Derivation of elastic fracture toughness for ductile metal pipes with circumferential external cracks under combined tension and bending

“…Extensive research has been conducted on calculating the stress intensity factors for surface cracks in pipes (e.g. Raju and Newman 1982;1986;Mettu et al 1992; Kou and Burdekin 2006;Li and Yang 2012). However, stress intensity factors thus obtained are only applicable to elastic materials and plastic materials under small scale yielding conditions (Anderson 1991).…”