Dynamic Stability Analysis Of Composite Frame With U-shape Steel-encased Concrete Composite Beam And Concrete-filled Square Steel Tubular

U-shape steel-encased concrete composite beam is a new type of steel and concrete composite beams, the composite frame with U-shape steel-encased concrete composite beam and concrete-filled square steel tubular is a kind of typical structure forms. But there is little research of this composite frame at present, especially the study of dynamic stability of the composite frame has not been reported.In this article we use the finite element theory to analyze the dynamic stability of this composite frame, the key of the analysis is the establishment of the finite element model.Typically,assuming beam-column joints as the ideally hinge or fully rigid-jointed whic h contributes to the simplify the design and calculation process,but in the actual structure,rigid ity of composite joints are normally in somewhere between complete rigid-joint and ideally hi nge-half rigid-joint.Since this paper proposed a advanced composite farmework stiffness of fra me beam-column joints and there are quite a few references about it,this paper conducts by fin ite element analysis methodology,targeted in solving the rotation relationship node,to identify t he finit element pattern in composite framework.By establishment of finite element model of composiite framework,systematically analy se the self vibration cycle and model of composite frame,conclude the dynamic behavoir of co mposite frame.Solution to damping coefficien for composite drame is made to support stability of dynamic behavoir of composite frame by necessary data.Through the dynamic analysis of the composite frame, research the dynamic response of different joint stiffness, different layers and the span numbers, and the type of seismic waves.Currently, research on the dynamic stability for construction are mainly focused on sp ace steel construct.rarely on the composite frame constructions.Based on the research of the j udgement on dynamic stability of spacial steel struction,analysis of transient dynamic bahavoi r on circumstance of seism.By study the curve of stability and unstablity of composite structur e, reveals the certain consistency transformation on displacement of time curve and phase plan e curve as well as energy time curve.Tracing the response changes in variations of earthquak e crest acceleration results in certify the critical acceleration of instability seismic wave been a ffected by second order effect of gravity when considering composite structure.Consideratio n of damping ratio, layers of composite framework and other factors like earthquake dynamic i mpact on stability of composite dyanamic.Finally,conclude the thesis and propose the outlook to the research.