PSI - Issue 18

Riccardo Fincato et al. / Procedia Structural Integrity 18 (2019) 75–85 Author name / Structural Integrity Procedia 00 (2019) 000–000

77

3

C i , B i : material parameters for the kinematic hardening : norm of a tensor ( :

 T T T , T generic second-order tensor)

if a a a 

0,

0 if

0  )

: Macauley’s bracket (

a

a





' T : deviatoric part of a generic second-order tensor T T  : generic second-order tensor in the undamaged configuration CDM: continuum damage mechanics OSS: overstress subloading surface model (Hashiguchi, 2009) DOSS: damage overstress subloading surface model DSS: damage subloading surface model (Fincato and Tsutsumi, 2017c) 2. The damage overstress subloading surface

The OSS model was initially proposed by Hashiguchi (2009) as a modification of the subloading surface model, an unconventional (Drucker, 1988) rate-independent elastoplastic theory. A detailed explanation of the constitutive equations of the OSS model can be found in Hashiguchi (2009) and Hashiguchi (2017), here a brief description of the model features are reported. Moreover, the present paper improves the theory by adding the similarity-center internal variable, for the description of cyclic mobility problems, together with a scalar isotropic ductile damage variable within the framework of the CDM.

a)

b) c) Fig. 1 (a) Sketch of the subloading surface, Normal-yield surface, and dynamic loading surface, (b) stress-strain curve predicted by the original overstress model, (c) stress-strain curves predicted by the overstress subloading surface model, red line for the quasi-static loading condition.