PSI - Issue 71

Sudarshan Solanki et al. / Procedia Structural Integrity 71 (2025) 95–102

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parameters have been calibrated from material specific cyclic stress-strain curves ( Chaturvedi’s ( 2013), Interim reports (2022)) typically corresponding to half-lives.

Table 1. Tensile properties of base and weld materials used in present DMW ([K umar’s 2016], [ Goyal’s 2011 ], [ Chaturvedi’s 2013 ])

Ultimate Tensile Strength (MPa)

Yield strength (MPa)

Material used in DMW

Total Elongation (%)

SA508 -Gr.3 Cl.1

570

695

19.5

SS304LN

207

580

82

SS308L

408

596

52

Fig. 2. Comparisons of tensile/cyclic stress strain curves for base and weld metals.

Table 2. Elastic and cyclic plasticity parameters for base and weld metals. E (GPa) (MPa) C 1 (MPa) γ 1 C 2 (MPa) 227 232.5 705000 5250 95000

Materials

γ 2

C 3 (MPa)

γ 3

LAS 508 Base Metal SS308L Weld Metal SS304LN Base metal [ Goyal’s 2011 ]

1050

9500 3200

200 #

287

150000

3000

37000

381

0.3

0

In present study, Chaboche’s material constants have been calibrated from existing cyclic stress-strain test data on SA-508 Gr.3 Cl.1 and SS308L materials. These material constants have been calibrated from representative sets of pure axial cyclic tests on SA 508 Gr. 3 Cl.1, SS308L. The Chaboche constants for SS 304LN were calibrated by Goyal et al. (2011) and are directly used in FE analyses. The Chaboche material constants are given in Table 2 for two base and one weld metals. 4. Details of FE analyses 4400 # The Young's modulus (E) of SS308L weld metal was approximated using monotonic stress-strain curve [ Chaturvedi’s 2013 ]. 195 182 100000 10000 67000 381

(a) (b) Fig. 3. (a) Comparison for equivalent strain amplitude along cylinder axis for coarse and fine meshes and; (b) Finite element models with boundary conditions for pure axial and pure torsional loadings applied remotely.