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Hardening and non-associated flow NURBS plasticity.

Coombs, W.M (2017) 'Hardening and non-associated flow NURBS plasticity.', in Proceedings of the XIV International Conference on Computational Plasticity. Fundamentals and Applications (COMPLAS 2017), 5-7 September 2017, Barcelona, Spain. Barcelona: International Center for Numerical Methods in Engineering (CIMNE), pp. 363-372.


In numerical analysis the failure of engineering materials is controlled through specifying yield envelopes (or surfaces) that bound the allowable stress in the material. Simple examples include the prismatic von Mises (circle) and Tresca (hexagon) yield surfaces. However, each surface is distinct and requires a specific equation describing the shape of the surface to be formulated in each case. These equations impact on the numerical implementation (specifically relating to stress integration) of the models and therefore a separate algorithm must be constructed for each model. Recently a framework was proposed that allows any isotropic yield surface to be represented by a NURBS surface and the constitutive model formulated using the name numerical algorithm. This paper presents, for the first time, an extension to this framework to allow both hardening (expansion/contraction of the surfaces) and a non-associated plastic flow rule. As with previous work on NURBS plasticity, the constitutive framework is combined with an implicit backward-Euler-type stress integration algorithm. The numerical performance of the algorithm is demonstrated using both material point investigations and boundary value simulations.

Item Type:Book chapter
Full text:(AM) Accepted Manuscript
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Date accepted:25 August 2017
Date deposited:29 August 2017
Date of first online publication:2017
Date first made open access:No date available

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