An Adaptive VEM Framework for Plane-Strain Limit Analysis
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We propose a new adaptive Virtual Element Method (VEM) scheme for the kinematic limit analysis of two-dimensional cracked structures, designed to bypass several difficulties typically encountered in standard finite element approaches. VEM is a stabilized Galerkin formulation defined on general polytopal meshes, where shape functions are implicit (“virtual”) and do not need to be explicitly constructed within the element domain [1]. Element contributions are computed through suitable projection operators, which split the discrete bilinear form into a polynomially consistent term and a stabilization term ensuring robustness. The proposed strategy exploits higher-order VEM features to support a general mesh-refinement procedure based on a conforming polytree structure, while preventing volumetric locking. The formulation accommodates arbitrary polygonal elements, with triangles and quadrilaterals recovered as particular cases. In this work we focus on plane-strain limit analysis of von Mises-type materials, although extension to other constitutive models is straightforward [2]. Adaptivity is driven by an L2-based strain-rate indicator. Numerical tests demonstrate that the method delivers accurate collapse-load predictions at a relatively low computational cost, enabling the efficient solution of large-scale limit analysis problems. REFERENCES [1] Beirão da Veiga L, Brezzi F, Cangiani A, Manzini G, Marini LD, Russo A., 2013, Basic principles of virtual element methods, Mathematical Models and Methods Applied Sciences, 23, 199-214. [2] Nguyen-Xuan H, Nguyen-Hoang S, Rabczuk T, Hackl K., 2017, A polytree-based adaptive approach to limit analysis of cracked structures, Computer Methods in Applied Mechanics and Engineering, 313, 1006-1039.
