Large elastoplastic deformation prediction for stiffened plate based on incremental absolute nodal coordinate formulation

Elastoplastic deformation with significant reference rotation of large stiffened plate is hard to be predicted effectively using conventional FEM and analytical methods, due to high flexibility of thin-walled structures and structural complexity of stiffeners. An accurate and effective model for the large elastoplastic deformation prediction is thus essential for both the deformation analysis and the deviation control. In this paper, a discretized modeling approach for stiffened plates is proposed for large elastoplastic deformation prediction by using the incremental absolute nodal coordinate formulation (ANCF). The incremental ANCF is developed to express the nodal displacement and the variations of elastoplastic strain and stress during the static loading are considered. The stiffeners and the skin of stiffened plate are constructed using ANCF beam elements and plate elements, respectively. The deformation compatibility on the interface between skin and stiffeners is introduced as constraint equations for the solution of the interaction forces on the interface. Subsequently, the static equilibrium equations of the assembled elements and the deformation compatibility equations are used to constitute the global equations for solving the nodal displacement of stiffened plates. The deformation of stiffened plate by the proposed method is validated to be converged within the small number of beam/plate elements compared with that by commercial finite element software. The solutions of large elastoplastic deformation with various loading conditions are also investigated by using the proposed method, by which the prediction accuracy for complex stiffened plates is verified.