Isogeometric Analysis of Nearly Incompressible Large Strain Plasticity
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TEXAS UNIV AT AUSTIN INST FOR COMPUTATIONAL ENGINEERING AND SCIENCES
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We study the behavior of NURBS-based Isogeometric Analysis on problems of large-deformation plasticity. We evaluate the performance of standard NURBS elements and elements based on the F formulation of Elguedj et al. We determine that standard measures of evaluation employed in the literature, namely, displacements at selected locations and graphs of reaction forces versus displacements, are often misleading. On the other hand, stress distributions, in the form of contour plots, are the most revealing measure of element performance. We also determine that the concept of mesh locking, which has dominated investigations of low-order elements, is not a relevant issue for higher-order NURBS elements for problems of large-deformation plasticity. However, standard higher-order NURBS elements of type Qk, of continuity class Ck-1, k is greater than or equal to 2, typically exhibit spurious stress oscillations, whereas the F elements of type QkQk-1 produce good results in all cases.