Study On Mechanical Performance Of Out-of-Plane Skewed Connection With Reduced Beam Section Under Failure Of The Central Column

In recent years,due to the complex planar layout of many modern buildings,nonorthogonal connection joints have emerged,which is beneficial to improve the functional and aesthetic performance of the building structure.In addition,weakening the beam flange can make the plastic hinge move outward,thereby protecting the node domain and preventing brittle failure..The mechanical performance of the non-orthogonal connection with reduced beam section under failure of the central column has not been studied yet.Therefore,this paper focuses on the mechanical performance of out-of-plane skewed connection with reduced beam section under failure of the central column.Firstly,the finite element analysis software ABAQUS is used to establish a refined numerical analysis model of the out-of-plane skew connection with reduced beam section,and the existing relevant experiments are selected for numerical simulation to verify the effectiveness and rationality of the finite element simulation.Secondly,three types of models are established,namely,the traditional out-of-plane skew connection(BASE class node),the out-of-plane skew connection of flange weakening type in the weakening area perpendicular to the beam flange(RBS class node)and the out-of-plane skew connection of flange weakening type in the weakening area parallel to the column flange(PRBS class node).Compared with the orthogonal connection,the force performance of the three joints is compared and analyzed,and the influence of different skew angles and different weakening modes on the force of the flange weakened non-orthogonal connection node,failure mode,deformation form and resistance mechanism is studied.Finally,a parametric analysis is carried out on the out-of-plane skew connection with reduced beam section under different skew angles to study the influence of weakening methods and weakening parameters on their collapse resistance performance,and reasonable suggestions are made on the flange weakening methods and related parameters of the connection under different skew angles.The results show that,for BASE joints,the increase of out-of-plane skew angles has an adverse effect on the deformation capacity and bearing capacity of the joints.After the node adopts RBS weakening mode,its deformation capacity and bearing capacity are almost not affected by the skew angle.After the node adopts PRBS weakening mode,the deformation capacity and bearing capacity of the joints are improved due to the out-ofplane skew in the beam.When the skew angle reaches 30°,the mechanical properties of the joints are greatly improved.Reasonable weakening modes and parameters have a great impact on the bearing capacity and the development of resistance mechanism of nodes,among which,the depth of the weakening area c has the most significant impact on the performance of the node.