• A novel hybrid isogeometric element based on two-field Hellinger– Reissner principle to alleviate different types of locking

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    • Keywords

       

      Isogeometric analysis; Hellinger–Reissner principle; Hybrid isogeometric analysis; Locking; Finite element analysis; Mixed formulation.

    • Abstract

       

      In the present work, novel hybrid elements are proposed to alleviate the locking anomaly in non-uniform rational B-spline-based isogeometric analysis (IGA) using a two-field Hellinger–Reissner variational principle. The proposed hybrid elements are derived by adopting the independent interpolation schemes for displacement and stress fields. The key highlight of the present study is the choice and evaluation of higher-order terms for the stress interpolation function to provide a locking-free solution. Furthermore, the present study demonstrates the efficacy of the proposed elements with the treatment of several two-dimensional linear-elastic benchmark problems alongside the conventional single-field IGA, Lagrangian-based finite element analysis (FEA), and hybrid FEA formulation. It is shown that the proposed class of hybrid elements performs effectively for analyzing the nearly incompressible problem domains thatare severely affected by volumetric locking along with the thin plate and shell problems where the shear locking is dominant. A better coarse mesh accuracy of the proposed method in comparison with the conventional formulation is demonstrated through various numerical examples. Moreover, the formulation isnot restricted to the locking-dominated problem domains but can also be implemented to solve the problems of general form without any special treatment. Thus, the proposed method is robust, most efficient, and highly effective against both shear and volumetric locking.

    • Author Affiliations

       

      DHIRAJ S BOMBARDE1 SACHIN S GAUTAM1 ARUP NANDY1

      1. Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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