Nonlinear Dynamic Analysis Of K8 Single-Layer Latticed Domes

Grid shell has characteristics of great rigidity,light weight,magnificent structure, and good synthetic technology index.It is one of the main large span structural styles.At present,domestic documentation has getten many achievements in static and dynamic natures of grid shell.K8 latticed domes is a kind of single-layer grid shell.The determinant of design of single-layer shell structures is stability but not lied on strength.At present,researches about the static behavior and geometrically nonlinear static stability of cylindrical orthogonal single-layer lattice shell structures have been consummate.But as to geometrically nonlinear dynamic stability of the structure under the earthquake loads,the researches are in the studing.Based on nonlinear finite element theory,the tangent stiffness matrix in space frames is deducted and the program of nonlinear dynamic stability is complied.The acceleration values of seismic loads and the duration of the earthquake are adjusted by proportion method,so that the peak value of acceleration and the duration of the earthquake answer calculation needs.The dynamic responses of K8 single-layer latticed domes structures supported by peripheral fixed supportand peripheral hinge support are calculated under seismic of different acceleration.So the displacements of nodes of the shell structures are got and the displacement of the each node can be found.The curve of displacement of nodes under dynamic acceleration and curve of displacement history of the nodes of shell structures can be drawn,the curve of configuration of the structure and the instable point can ben found,the dynamic stability critical loads of K8 single-layer latticed domes structures is estimated thought B-R rules.The results show that,through this method the dynamic stability critical loads of the grid shell structures under seismic loads can be effectively determined.Through changing the duration of seismic waves,the impact of the duration of seismic waves on dynamic stiffness and dynamic stability of the structure are analyzed,and the critical loads under different duration of seismic waves can be found througth B-R rules.At the same time,in the paper dynamic stability of K8 single-layer latticed domes are analyzed considering different structural parameter,for instence ratio of rise to span, support forms,the duration of seismic waves etc.So some useful conclusions of the seismic resistence design are given for the engeneering,and some questions of the structure that should be resolved in the future are discussed.