PSI - Issue 37

Cheng Qian et al. / Procedia Structural Integrity 37 (2022) 926–933 Cheng Qian et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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2

Nomenclature a

crack size

original crack size

a 0 A 1 A 2

parameter in J - A 2 solution constraint parameter bending modified A 2 parameter

A 2 BM

A p constraint parameter A PEEQ area surrounded by an equivalent plastic strain isoline ahead of the crack tip A ref A PEEQ - value of a reference specimen C p constraint parameter E elastic modulus h constraint parameter H specimen daylight length HRR crack-tip singularity field proposed by Hutchinson, Rice and Rosengren I n integration constant in HRR solution J energy release rate J 0.2 BL J -values corresponding to crack extensions of 0.2 mm blunting line J mid local J -value at the mid-plane at the crack front k 1 , k 2 linear fitting coefficients between J 0.2 BL (or  0.2 BL ) and Y L characteristic lengths that are commonly set as 1 mm SSY large-scale yielding n strain hardening exponent Q constraint parameter Q BM bending modified Q HRR parameter Q HRR Q parameter obtained from the HRR solution Q LM load-dependent modified Q HRR parameter Q SSY Q parameter obtained from the SSY solution r,  coordinates in the polar coordinate system at the crack tip R 2 coefficient of determination S specimen span s 1 , s 2 , s 3 stress power exponents in the J - A 2 solution SSY small-scale yielding T z constraint parameter V p constraint parameter W specimen width Y general constraint parameter  a crack extension  coefficient in the Ramberg-Osgood stress-strain relation  0 reference strain,  0 =  0 / E  p equivalent plastic strain  0 reference stress  e von Mises stress  ij stress tensor  m hydrostatic stress   opening stress ahead of the crack tip ᷉ ij dimensionless functions of n ,  in the HRR solution ᷉ ij ( k ) angular functions in the J - A 2 solution  CTOD, crack tip opening displacement  0.2 BL CTOD-values corresponding to crack extensions of 0.2 mm blunting line