Finite Element Analysis And Behavior Of Semi-rigid Steel Frames With For Non-linearity And Material Nonlinear

Steel frame with welding joint easily occur brittle collapse because of having alow ductility at joints．Then,a semi-rigid connected steel frame has large the energyabsorption capacity which can resist dynamic loads and the using steel qualities ofbracing system and joints are small．So adopting a semi-rigid jointed steel frame iseconomical and stable．But for semi-rigid connections are complex and variable,inconventional analysis and design of steel structures,It is usually assumed that theconnections between columns and beams are either rigid or pinned．The analysis ofsteel frames adopting the assumption can simplify the procedure of analysis anddesign,but cannot precisely reflect structural practical circumstance and the errors ofcalculating results are large,even,get incorrect conclusions． Semi-rigid connection was referred to in Chinese Code for Design of Steel Structures(2001,10),however,it isn't specified how to apply semi-rigid joints in design．In fact it cannot be carry out．The purpose of the paper give a calculating method that accords practical engineering and easily put into effect．Worthwhile it isgoing to promote the development of semi-rigid jointed steel frame in design and heighten structural stability． In the paper,at first some commonly employed methods for the modeling of connection behavior are introduced．Richard．Abbott function modeling of connection is adopted for extended end plate bolted connection．By the 34 test data comparing to regression analysis indicate Richard-Abbott function modeling of connection represents an excellent fit to test data．Then after a semi-rigid joint behavior can be modeled as a finite stiffness rotation spring,base on rotation and displacement equation derive the element stiffness matrixes with semi-rigid connections where the effects ofj ointed flexibility geometric non-linearity and shear forces in the connection deformations have been considered in and fixed-end forces are modified．Finally,a program for calculating semi-rigid with incremental-iterative method has beencompiled for calculating and analyzing． By calculating results of several example decade for steel frame in semi-rigidjoints cases the top story deflection and the initial end moment at column is larger,nevertheless the end moment at beam may be smaller when compared to the rigidjoint case．Affect of the semi-rigid joint Can be reduced by the use of bracingmembers．Influences of second order effect and shear forces in the connection deformations are larger when the semi-rigid j oint case is compared to the rigid j ointcase．Base on static and analysis of calculating results the range of the joint stiffness isput forward when influence of the semi-rigid joint is irrespective and parameter modified of inter force and displacement is given when influence of the semi-rigidjoint is considered that offers advice for in actual design...