Nonconforming variable-node axisymmetric solid element

This paper addresses the development of a nonconforming axisymmetric quadrilateral variable-node element which is designated as NAQV. The NAQV element is an improved version of the axisymmetric quadrilateral variable-node (AQV) element by adding nonconforming modes selectively. Both NAQV and AQV elements are effectively used in overcoming some problems in connecting the different layer patterns in the adaptive h refinement on a quadrilateral mesh. The use of elements with variable nodes eliminates the necessity of imposing displacement constraints on irregular (hanging) nodes in order to enforce the interelement compatibility. Therefore, the NAQV and AQV elements can be used effectively in the local mesh refinement for the axisymmetric structures which have stress concentrations. As verified through some numerical tests, the NAQV element shows excellent performance and can be used in the analysis of practical problems.