Remedies to rotational frame dependence and interpolation failure of US-QUAD8 element

摘要

It is known that the recently introduced unsymmetric 8-node quadrilateral element (US-QUAD8) is highly tolerant to mesh distortions. The high distortion tolerance of US-QUAD8 is due to the ability of the element to satisfy all the desirable compatibility and completeness requirements of the test and trial functions. The element uses isoparametric and metric shape functions as the test and trial functions, respectively. Despite its high distortion tolerance, the element has two defects. The use of metric shape functions as trial functions causes the element to exhibit rotational frame dependence as well as interpolation failure under certain conditions. A detailed investigation into both these problems is reported and remedies are proposed.