Optimal spectral approximation of2n-order differential operators by mixed isogeometric analysis

Autor: Victor M. Calo, Quanling Deng, Vladimir Puzyrev
Rok vydání: 2019
Předmět:
Zdroj: Computer Methods in Applied Mechanics and Engineering. 343:297-313
ISSN: 0045-7825
DOI: 10.1016/j.cma.2018.08.042
Popis: We approximate the spectra of a class of 2 n -order differential operators using isogeometric analysis in mixed formulations. This class includes a wide range of differential operators such as those arising in elliptic, biharmonic, Cahn–Hilliard, Swift–Hohenberg, and phase-field crystal equations. The spectra of the differential operators are approximated by solving differential eigenvalue problems in mixed formulations, which require auxiliary parameters. The mixed isogeometric formulation when applying classical quadrature rules leads to an eigenvalue error convergence of order 2 p where p is the order of the underlying B-spline space. We improve this order to be 2 p + 2 by applying optimally-blended quadrature rules developed in Puzyrev et al. (2017), Caloet al. (0000) and this order is an optimum in the view of dispersion error. We also compare these results with the mixed finite elements and show numerically that the mixed isogeometric analysis leads to significantly better spectral approximations.
Databáze: OpenAIRE