PSI - Issue 60

N. Khandelwal et al. / Procedia Structural Integrity 60 (2024) 582–590 Author name / StructuralIntegrity Procedia 00 (2019) 000 – 000 Furthermore, ductility effect in crack propagation stages is dealt with J2-plasticity theory, where yield function ( ) and plastic strain ( ) are defined as: = √3 2 - ( ) ( ) ≤0 (8) ̇ = ̇ ̇ (9) Where is second invariant of deviatoric stress tensor, ̇ is the plastic consistency factor, ( ) is the hardening function and represent equivalent plastic strain. Numerical implementation of proposed formulation is solved using three-dimensional eight-noded hexahedral elements using user defined subroutines linked with ABAQUS in staggered manner as discussed in details by Khandelwal and Murthy (2023). 3. Specimen geometry and loading details The two pipe specimens (SSPW 6-25 and SSPW 12-27) considered in the study are made up of 304 LN stainless steel material conforming to ASTM A 312 - 09 specifications having material properties as presented in Table 1. Initially, both the pipes had through-wall circumferential V-shaped notch with notch angle of approximately 60  at the centre of the pipe as shown in Fig. 2. The pipes were simply supported with hinge support at one end and roller support at the other end on outer span ( ) to simulate four-point bending with constant bending moment between the two loading points on inner span ( ) with the typical loading arrangement as shown in Fig. 3. The geometrical details of the pipe specimens are given in Table 2. The pipes were fabricated and supplied by Bhabha Atomic Research Centre (BARC, India) and tested in the CSIR-Structural Engineering Research Centre. (Vishnuvardhan et al., 2010a, 2010b). 585 4

Table 1. Mechanical properties of 304LN stainless steel pipe specimen (Vishnuvardhan et al., 2010a, 2010b) Properties Values Yield strength ( ) 251 Young’s modulus ( ) 183 Hardening modulus ( ) 1850 Critital energy release rate ( / ) 1000

2

Notch tip A

Notch tip B

Fig. 2. Details of a straight pipe with circumferential through-wall notch .

Section on A-A

Notch