Large deflection behavior simulation of RC shear walls by a VFIFE based planar four-node element

For shear walls under vertical and horizontal load, large deflection will cause difficulty to reach accurate simulation result for traditional continuum method even with fine mesh element. Furthermore, concrete material nonlinearity, stiffness degradation, concrete cracking and crushing, as well as steel bar damage can occur during the large deflection of reinforced concrete (RC) shear walls. Matrix operation involved nonlinear problems by traditional finite element method (FEM), however, often result in illness of matrix, which lead to difficulty in reaching accurate solutions. To solve these problems, a planar four-node element was developed based on the vector form intrinsic finite element (VFIFE) theory for the advantage of particle description and time path which exempt global stiffness integration. The composite nonlinear concrete constitutive model and bilinear steel material model are adopted and programed for this VFIFE planar four-node element, which extend to large deflection and damage behavior. As verification examples, a group of experimental RC shear wall simulation subjected to constant vertical load and continuously increasing lateral load was conducted. Loading speed, meshing dimension and the damping factor used in the simulation were tested. The simulated pushover response including the bearing capacity, the deformation ability, the curvature development and the energy dissipation were in good accordance with experimental observations. Additionally, as the cracking and crushing criteria defined, the predicted fracture development can also be analyzed as example demonstrated. Proposed research examples exhibit a potential uniformed whole deflection process to large deflection and damage simulation analysis method by this developed element and program. Copyright © 2019 Techno-Press, Ltd.