Static Analysis On The Space Reticulated Shells With Semi-rigid Connections

Space shell has beautiful structure shape and excellent mechanics performance. It is one kind of space structures used extensively in the recent years. In traditional space shell analysis, the behavior of bars connections is treated as either pinned or rigid joints entity. While lots of constructions and theory experiments proved that the bars connections is between pinned and rigid, namely semi-rigid. Because in practical construction, to a certain extent, so-called pinned joints possess rigidity, and so-called rigid joints possess flexibility. Though this idealistic hypothesis can simplify the design and analysis process largely, it engenders the large difference of theory and practice, the structure's insecurity or conservation and is not worth the money. This paper analyses the static performance on the reticulated shells with semi-rigid connections under the present situation.Firstly, simulating the semi-rigid connections as rotatable springs at both ends, the element stiffness matrix of the space bar with semi-rigid connections is derived on the basis of the definition of the element stiffness. With the same method the formula which convert the load acting on the span of the bar into the load acting on the nodes is derived. The models is validated by using finite elements program. Using the established models, the subroutine UEL has been made.Secondly, the finite element models are established and analysised with the UEL. So the static analysis of space shells with rigid connections and with semi-rigid connections and with pinned connections are carried through. After comparing and analyzing, some conclusions about the behavior of space shell with the semi-rigid connections are drawn. The results reveal the effect of the joint's stiffness on the structure's static characteristics, implying that the joint's stiffness should be taken into account and appropriate combinations of the parameters should be adopted in structural design .Finally, the static performance on the space shells with semi-rigid connections is summed up and suggestions are proposed for further research.