A procedure to locally refine and un-refine an unstructured computational grid of four-node quadrilaterals (in 2D) or of eight-node hexahedra (in 3D) is presented. The chosen refinement strategy generates only elements of the same type as their parents, but also produces so-called hanging nodes along non-conforming element-to-element interfaces. Continuity of the solution across such interfaces is enforced strongly by Lagrange multipliers. The element split and un-split algorithm is entirely integer-based. It relies only upon element connectivity and makes no use of nodal coordinates or other real-number quantities. The chosen data structure and the continuous tracking of the nature of each node facilitate the treatment of natural and essential boundary conditions in adaptivity. A generalization of the concept of neighbor elements allows transport calculations in adaptive fluid calculations. The proposed procedure is tested in structure and fluid wave propagation problems in explicit transient dynamics.

CASADEI Folco;  DIEZ Pedro;  VERDUGO Francesc; 

2013-10-09

WORLD SCIENTIFIC PUBL CO PTE LTD

JRC64852

0219-8762,   

http://www.worldscientific.com/doi/abs/10.1142/S0219876213500187,    https://publications.jrc.ec.europa.eu/repository/handle/JRC64852,   

10.1142/S0219876213500187,