Transfer Mechanism Test Analysisand Static Calculation Program Research On Foldable Space Structure Of Seven Rectangular Arc

Foldable space structure of seven rectangular arc is a new type of space structure,which is made up of nearly seven hundreds of root bars in certain rules with the help of the connection of the hub node. Given its repeated usage, foldability and large space and easy storing, the structure is widely applied into the construction and military projects.Currently Chinese research of the structure is less, the performance, mechanism and other problems of the expansion structure subjected to load stress is not well understood,and no special static calculation program is used for the numerical calculations. So this paper has important theoretical significance and engineering practical value for the analysis of the load transfer mechanism and the development of the static calculation program for the foldable space structure of seven rectangular arc. The main research contents and results are:1.The transfer mechanism test on the foldable space structure of seven rectangular arc is completed under the function of vertical load. Results show that:(1) while the external load is applied on G4 hub node, G4G5’、G4G3’ members is accounted for about70% of sharing internal force. path of force transfer mainly along the route G4G5’-G4G3’-G3’G2-G2’G1.(2) when the external load is applied on H4 hub node,firstly transfer to the corner of hub nodes through the spoke bar and about 70% of the load continue to transfer along the route G4G3’-G3’G2-G2’G1, about 30% of the load,transfer to the adjacent frame grids rod.(3) while external load is applied on the A5 hub node, of the node connected rods, A5A4’、A5A6’ members is accounted for about 75%of sharing internal force, load mainly transfer along the main structure of a shaft leverforce transmission; path of force transfer mainly along the route of A5’U2-S2U2’-S2’r2member transfer to the ground in gable structure.2.Test analysis show that: shear rod in the pivot point produce larger bending stress,while studying seven arch folded truss structure model and numerical analysis, we must take effect of the shearing rod to pivot nodes the bending internal force in account, to be more in line with shear rod unit the actual mechanics model.3.The two “single shot” element of the seven arch folded truss structure are considered as a macro-element and based on the stiffness matrix of two node beam element, we first derive the “single pole” element stiffness matrix, and the integrate“single shot” single rigid to macro element stiffness matrix, with fortran programming language, the moment seven arch folded grid structure static calculation program is written. Using the program of numerical calculation, comparing the calculated values and test values, results show that the calculation results are agree well with the experimental results.4.The numerical calculation about the foldable space structure of seven rectangular arc is completed under the action of snow load, combining with the analysis of the calculation results, it is showed that the force transfer mechanism of the foldable space structure under vertical loading is: forming a skeleton structure,the arch sub grid is the main bearing system, each unit crossing spoke to stem is the secondary to load transfer and to bear, the pin rod only plays a part of horizontal contacting.