Study On The Stability Of Cable-stiffened Single-layer Latticed Shell Considering The Defects Of Joint Stiffness And Cable Force Loss

The cable-stiffened single-layer latticed shell is a kind of large-span spatial structure,which is a mixed spatial structure system formed by applying prestressed cables on the single-layer reticulated shell.While fully improving the stability of the single-layer reticulated shell,it can also increase the structural bearing capacity,reduce its own weight,and have the advantages of good permeability and lighting performance.It is very suitable for building structures with free-form surfaces.At present,the relevant research considering the effect of defects on the stability of cable-stiffened single-layer latticed shells is mainly focused on the initial geometric defects,while related theories and researches on cable-supported reticulated shells with other types of defects are insufficient,which restricts its use in practical engineering.Therefore,this paper analyzes and studies the stability of cable-supported reticulated shells with joint stiffness defects and cable force loss defects.By means of mechanical and theoretical analysis,the influence of the two defects on the stability of cable-stiffened single-layer latticed shells was studied respectively,And put forward the analysis method of asymmetry degree,which provided data support for the engineering application and promotion of the cable-brace reticulated shell.The main content of this paper includes:1.Study on the stability of cable-stiffened single-layer latticed shells with joint stiffness defectsBased on ANSYS,the finite element models of the semi-rigidly jointed reticulated domes were established,and analysis of several typical types of cable-supported reticulated shell structures.In the case of the same or random joint stiffness defect distribution,the influence of the defect on the stability of cable-stiffened single-layer latticed shells is summarized.The results show that the joint stiffness defects have little effect on the stability of hyperbolic elliptic paraboloid and spherical cable-supported reticulated shells.And the cable-stiffened single-layer cylindrical latticed shells supported along two longitude edges may appear two different instability mode,one is positive symmetric instability with higher bearing capacity,and the other is lateral instability with lower bearing capacity,the latter’s carrying capacity is only 2/3 of the former.2.Instability mode discrimination method of cable-stiffened single-layer cylindrical latticed shells based on"asymmetry degree"The reasons for the two instability modes of the cable-stiffened single-layer cylindrical latticed shells supported along two longitude edges under random joint stiffness defects are analyzed.According to the distribution of node stiffness,the concept and calculation method of asymmetry degree are put forward.It is determined that the critical value of asymmetry degree when the structural instability mode changes isβ₀=1.When the asymmetry degreeβ<1,the structure will undergo positive symmetrical instability,Whenβ≥1,the structure will lateral instability.Through parameter analysis,the applicability of asymmetry degree is verified.Meanwhile,analyzed the relationship between the parameters in the formula and the structural deformation.3.Study on stability of cable-stiffened single-layer latticed shells considering cable force loss defectBased on ANSYS,a refined numerical analysis model of cable-stiffened single-layer latticed shells with cable force loss defects was established.The stability performance of several typical structures with different cable force loss defects are analyzed respectively.Through a large number of calculation examples,it is shown that the cable force loss defect has a greater impact on the stability of the hyperbolic elliptical paraboloid and spherical cable-stiffened single-layer latticed shells,but basically has no effect on the cylindrical cable-stiffened single-layer latticed shells supported on four sides.