Quantitative analysis of deformation performance for skew slab based on deformation energy decomposition method of triangular prism element

In order to propose a simpler and more effective method to quantitatively analyze the macroscopic basic deformation properties such as tension, bending and shear of the skew slabs, and provide theoretical basis and technical support for targeted design and reinforcement. Based on mathematical orthogonality, mechanical equilibrium and physical parameters, this paper proposes a deformation energy decomposition method suitable for 3D 6-node arbitrary triangular prism elements. By applying this method to the finite element model discretized by triangular prism element, the quantitative information of 6 kinds of rigid body displacement and 12 kinds of deformation energy of skew slab can be obtained. The quantitative and visual analysis of the basic deformation performance of the skew slab is carried out by using the method in this paper. Then the targeted structural design and reinforcement design of the skew slab can be guided according to the principle of matching design with deformation. Compared with the existing deformation decomposition methods based on square elements, which are only applicable to 2D or quasi-3D regular structures, the deformation energy decomposition method based on arbitrary triangular prism elements in this paper can be used to analyze the deformation performance of 3D irregular structures. The influence of skew angle and span-width ratio on the deformation performance of skew slab is analyzed by deformation energy decomposition method. The results show that when the skew angle is greater than 25°, the proportion of ductile deformation energy such as tension and bending of skew slab decreases rapidly. In this case, the shear design of the skew slab should be focused on. When the angle is greater than 45°, the span-width ratio should be appropriately reduced to improve the ductility of the skew slab, and the torsion design needs to be focused on.