Research On The Mechanical Performance Of Castellated Lightweight Steel Portal Frame Beam-Column Joint

Castellated lightweight steel portal frame is a castellated type steel members used in portal frame structure of a new type of portal frame structure,this structure not only has the characteristics of large bearing capacity and high stiffness,but also retain the advantages of portal frame span large and light weight.In this new type of structure,the node as a connection of castellated column and beam,it is the key parts of structure to guaranteed work normally,it is also the important factors that limit this kind of structure development,so the research for the node of structure is particularly important.This article mainly discusses the mechanical performance of castellated lightweight steel portal frame beam-column joints.Summarized the research achievements of castellated type of steel members of the domestic and foreign scholars,used large-scale finite element software ABAQUS simulation analysis of the hexagonal hole castellated lightweight steel portal frame beam-column joints of the force performance and indicators.Respectively simulated the three research variables on the expansion ratio,hole distance,the node domain is set stiffening rib this grouping,explores the castellated lightweight steel portal frame beam-column joints of static performance and seismic performance.Through the comparative analysis draws the following conclusion:(1)The influence of expansion ratio on such nodes is larger,the influence of castellated nodes in the ability of bearing capacity,deformation characteristics,seismic performance is much better than the solid-web node,showed a trend of decrease with the increase of expansion ratio beam stress,expansion ratio 1.52 of the specimen is the best in the mechanical performance,expansion ratio 1.6 of the specimen is better than others,but this kind of specimen in the ultimate bearing capacity is poor;And expansion ratio 1.4 specimens although its domain stress is less than the solid-web node,but its stress distribution trend greatly more than the stress of the solid web node,cannot achieve the purpose of expansion.Castellated nodes in terms of hysteretic performance,stiffness,ultimate bearing capacity than the solid-web node is better,when the expansion ratio is 1.4 and 1.52,specimen showed good ductility;When the expansion ratio is 1.6,specimen showed poor seismic performance.(2)The influence of hole distance on such nodes is bigger,this is because that the hole distance determines the emergence of the plastic hinge location at the castellated component.Hole distance is 768 mm specimen stress,the maximum stress of the node domain are greater than the distance is 423 mm of specimen,and stress concentrated on the right side of the hexagonal hole angle points.With the increase of hole distance,the ductility of the specimen has a great improvement,at the same time the hysteretic performance,the ultimate load capacity and energy consumption ere increased.(3)The influence of whether the node domain set stiffening rib of solid-web and castellated node in maximum stress,the stress distribution on the beam flange is not big.Node domain Settings of stress of the stiffener of nodes in the node domain is slightly less than the node domain without stiffener node;A setting in the node domain stiffening rib does not change the maximum stress and stress distribution of nodes,only slightly improves the rigidity of the node,the ultimate bearing capacity,yield displacement,hysteretic and energy dissipation capacity are similar,but the node domain decorate stiffener can improve the node domain in stress distribution.