Accuracy and Robustness of the Interpolation Cover Method for Structural Analysis: Effects of Neighboring-Node Selection and Polynomial Enrichment

This paper aims to analyze the performances of the interpolation covers method in the enrichment of a standard four-node quadrilateral finite element (FE) solution. The interpolation covers (IC) method has shown to be efficient in the local enrichment of the solution by increasing the polynomial degree of approximation using neighboring elements within a predefined set of covers. The enriched FE approximation is capable of capturing high stress gradients accurately, even using coarse mesh, thereby reducing the computational cost. As reported in existing studies, researchers have used neighboring nodes and polynomial enrichment to construct interpolation covers, but the combined effect of the selection of the number of neighboring nodes and their position in the patches and polynomial enrichment has not explored been yet. This study therefore performs a parametric investigation of these factors for enriched four-node, quadrilateral-shell finite elements. Two numerical applications are treated to demonstrate the effectiveness of the method. It is found that the selection of the closest neighboring nodes results in high solution accuracy.