The concept of reduced plastic dissipation is introduced for a perfectly plastic rate-independent material not obeyng the associated normality rule and characterized by a strictly convex plastic potential function. A maximum principle is provided and shown to play the role of variational statement for the nonassociative constitutive equations. The Kuhn-Tucker conditions of this principle describe the actual material behaviour as that of a (fictitious) composite material with two plastic constituents, each of which is associative in some suitably enlarged stress and strain spaces. The proposed principle is shown to identify with the classical one in case of associative plasticity. A simple illustrative example is reported.
Per un materiale perfettamente plastico (privo di effetti viscosi) di tipo non associativo e caratterizzato da una funzione potenziale plastico strettamente convessa, si introduce il concetto di dissipazione plastica ridotta. Si propone un principio di massimo e si mostra che esso rappresenta una formulazione variazionale delle equazioni costitutive della plasticità non associativa. Le condizioni di Kuhn-Tucker relative al suddetto principio descrivono il comportamento costitutivo del materiale reale come quello di un materiale (fittizio) composito con due costituenti ciascuno dei quali è di tipo plastico associativo in taluni spazi di tensioni e di deformazioni opportunamente ampliati. Il principio proposto si identifica con quello classico nel caso di plasticità associativa. Si riporta una semplice applicazione illustrativa.
@article{RLIN_1998_9_9_2_115_0, author = {Castrenze Polizzotto}, title = {A maximum reduced dissipation principle for nonassociative plasticity}, journal = {Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni}, volume = {9}, year = {1998}, pages = {115-129}, zbl = {0922.73015}, mrnumber = {1677266}, language = {en}, url = {http://dml.mathdoc.fr/item/RLIN_1998_9_9_2_115_0} }
Polizzotto, Castrenze. A maximum reduced dissipation principle for nonassociative plasticity. Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni, Tome 9 (1998) pp. 115-129. http://gdmltest.u-ga.fr/item/RLIN_1998_9_9_2_115_0/
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