Variable-node axisymmetric solid element and its application to adaptive mesh refinement

This paper presents an effective application of a variable-node axisymmetric solid elementdesignated as AQV (Axisymmetric Quadrilateral Variable-node element). The variable-node element withphysical midside nodes helps to overcome some problems in connecting the different layer patterns on aquadrilateral mesh in the adaptive h-refinement. This element alleviates the necessity of imposingdisplacement constraints on irregular (hanging) nodes in order to enforce the inter-element compatibility.Therefore, the elements with variable mid-side nodes can be used effectively in the local mesh refinementfor the axisymmetric structures which have stress concentrations. A modified Gaussian quadrature shouldbe adopted to evaluate the stiffness matrices of the variable-node elements mainly because of the slopediscontinuity of assumed displacement within the elements. Some numerical examples show the usefulnessof variable-node axisymmetric elements in the practical application.