Stress‐driven integration strategies and m‐AGC tangent operator for Perzyna viscoplasticity and viscoplastic relaxation: application to geomechanical interfaces |
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| Authors: | I. Aliguer I. Carol S. Sture |
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| Affiliation: | 1. Geotechnical Engineering and Geo‐Sciences Department (DETCG) ETSECCPB (School of Civil Engineering), UPC (Universitat Politécnica de Catalunya), Barcelona, Spain;2. Department of Civil, Environmental, and Architectural Engineering, University of Colorado at Boulder, Boulder, CO, U.S.A. |
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| Abstract: | The paper proposes a stress‐driven integration strategy for Perzyna‐type viscoplastic constitutive models, which leads also to a convenient algorithm for viscoplastic relaxation schemes. A generalized trapezoidal rule for the strain increment, combined with a linearized form of the yield function and flow rules, leads to a plasticity‐like compliance operator that can be explicitly inverted to give an algorithmic tangent stiffness tensor also denoted as the m‐AGC tangent operator. This operator is combined with the stress‐prescribed integration scheme, to obtain a natural error indicator that can be used as a convergence criterion of the intra‐step iterations (in physical viscoplasticity), or to a variable time‐step size in viscoplastic relaxation schemes based on a single linear calculation per time step. The proposed schemes have been implemented for an existing zero‐thickness interface constitutive model. Some numerical application examples are presented to illustrate the advantages of the new schemes proposed. Copyright © 2016 John Wiley & Sons, Ltd. |
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| Keywords: | viscoplasticity viscoplastic relaxation finite element method interface elements |
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