Properties and simplifications of constitutive time-discretized elastoplastic operators

0399485 - ÚGN 2015 RIV DE eng J - Journal Article
Sysala, Stanislav
Properties and simplifications of constitutive time-discretized elastoplastic operators.
ZAMM-Zeitschrift fur Angewandte Mathematik und Mechanik. Roč. 94, č. 3 (2014), s. 233-255. ISSN 0044-2267. E-ISSN 1521-4001
R&D Projects: GA MŠMT ED1.1.00/02.0070
Institutional support: RVO:68145535
Keywords : elastoplasticity * convex analysis * projection, semismoothness
Subject RIV: BA - General Mathematics
Impact factor: 1.162, year: 2014
http://onlinelibrary.wiley.com/doi/10.1002/zamm.201200056/pdf

In the paper, a general constitutive elastoplastic model for associated plasticity is investigated. The model is based on the thermodynamical framework with internal variables and can include basic plastic criteria with a combination of kine- matic hardening and non-linear isotropic h ardening. The corresponding initial val ue constitutive elastoplastic problem is discretized by the implicit Euler method. The discretized one-time-step constitutive pr oblem defines the elastoplastic operator, which is formulated by a simple generalization of a projection onto a convex set. Properties of the so-called generalized projection are used for deriving basic propertie s of the elastoplastic operator like potentiality, monotonicity, Lipschitz continuity and local semismoothness. Further, hardening variables are eliminated from the projective definition of the elastoplastic operators, which yields relations among the models with hardening variables and the perfect plasticity model. Also a simplification of the operator for plastic criteria in eigenvalue forms is introduced.
Permanent Link: http://hdl.handle.net/11104/0226794