Yj. Kim et al., FULLY PLASTIC CRACK-TIP FIELDS FOR PLANE-STRAIN SHALLOW-CRACKED SPECIMENS UNDER PURE BENDING, International journal of fracture, 78(1), 1996, pp. 21-34
Detailed finite element (FE) analyses are performed to study the effec
t of crack depth on crack-tip constraint at full yielding for pure ben
ding of plane strain single-edge-cracked specimens. Analyses are based
on small-strain formulations and perfect plasticity. The crack depth
a/W ranges from 0.1 to 0.7, and the deformation is applied up to the l
imiting state of full plasticity where crack-tip stresses reach steady
-state limiting values. At load levels smaller than the limit load (co
ntained yielding), the crack-tip constraint (stress triaxiality) gradu
ally decreases as a/W decreases, but, at load levels close to the limi
t load (or at the limit load), it decreases very sharply. In terms of
a/W, tractable closed-form approximations for fully plastic crack-tip
stress and strain fields are proposed, and fully plastic values of cra
ck-tip stresses are re-phrased in terms of the Q-parameter [1,2]. The
role of crack-tip strains on fracture of shallow-cracked bending speci
mens is briefly discussed.