Analysis On Steel Frame-axillary Enhanced Node Mechanics Performance

Steel frame reinforced connections are new types of beam-column connectionsstudied more and more by experts at home and abroad in recent years, the workingprinciple is expand local beam flange in a certain distance from the column surface,make the plastic hinge form at the beam flange away from the weld between beam andcolumn, reach the design purpose of plastic hinge relocation, effectively protect theweak parts of the beam-column joints, improve the ductility of the structure, avoidbrittle failure and realize the design thought of the seismic code “strong node weakcomponent”.This article has designed four axillary plates reinforced beam-column nodes, onthe beam end flange plate (with transition plate) enhanced axillary node, under the beamflange plate (with transition plate) enhanced axillary node, under the beam flange platestrengthened-nodes and axillary plates reinforced beam symmetric node. Axillary platesfor the four different structural forms of enhanced node of ANSYS finite elementnumerical simulation, analysis and comparison of the mechanical properties of fourkinds of nodes, key elements include:1, The end flange of beam axillary plates under detailed derivation of calculationmodel for enhanced node process were given. Axillary plates changed of geometryparameters on the stress distribution of beam end nodes were analyzed.2, For four kind of different structure form of axillary board strengthened typenode, this article has designed15Finite Element Modeling as the scale ratio forone-second which basis axillary board thickness and length of changes.60reducedscale ratio of1/2Finite Element Modeling were designed to take low cyclereciprocating loading test by the software of ANSYS. The results of finite lelmentanalysis suggests that four kind of axillary board strengthened type node can effectivelytransfer the plastic hinge away from the beam end, they have full hysteresis curves,good ductility and energy dissipation capacity. Meet the minimum standards of seismic performance.3, As the axillary strengthened beam length increases, the ultimate strength, ductilityand hysteretic of nodes are improved,the energy capacity of nodes has decreased. Theless increase in thickness of axillary plates has a lesser impact on mechanical propertiesof the nodes. Axillary plate thickness equal to or less than thickness of flange can meetthe requirements. Recommendations on beam end flange and beam end flange underarmpit (with transition plate) enhanced node＇s armpit length is as long as (0.6-0.8）times of the beam height, end the wing trailing edge and the enhanced node＇s armpitlength is as long as (0.7-0.8）times of the beam height, the nodes of beam lengthsymmetric enhanced axillary plates of armpit length is as long as (0.5-0.7）times of thebeam height. The axillary plate thickness can be equal to or less than thickness of flangerim.4, For Finite Element Modeling results, comparative analysis of four kinds ofaxillary plates to enhance the mechanical properties of type node and drawn that beamend flange axillary plates which under enhanced bearing capacity of the nodesrepresenting the other three nodes had significantly reduced.The plastic deformationcapacity of beam symmetric axillary plates strengthened compared with the other threenodes had extent reduced.