A new one-point quadrature enhanced assumed strain (EAS) solid-shell element with multiple integration points along thickness: Part I-geometrically linear applications

Accuracy and efficiency are the main features expected in finite element method. In the field of low-order formulations, the treatment of locking phenomena is crucial to prevent poor results. For three-dimensional analysis, the development of efficient and accurate eight-node solid-shell finite elements has been the principal goal of a number of recent published works. When modelling thin- and thick-walled applications, the well-known transverse shear and volumetric locking phenomena should be conveniently circumvented. In this work, the enhanced assumed strain method and a reduced in-plane integration scheme are combined to produce a new eight-node solid-shell element, accommodating the use of any number of integration points along thickness direction. Furthermore, a physical stabilization procedure is employed in order to correct the element's rank deficiency. Several factors contribute to the high computational efficiency of the formulation, namely: (i) the use of only one internal variable per element for the enhanced part of the strain field; (ii) the reduced integration scheme; (iii) the prevention of using multiple elements' layers along thickness, which can be simply replaced by any number of integration points within a single element layer. Implementation guidelines and numerical results confirm the robustness and efficiency of the proposed approach when compared to conventional elements well-established in the literature.