The Stability Analysis Of Lamella Partial Double Layer Lattice Shell

Reticulated shell structure has many advantages. For example, it usually has a dainty sculpt, a reasonable load transfer, and a lighter weight; and it can also provide a longer span. Because these advantages of reticulated shell structure, it becomes more and more popular. Reticulated shell structure can be divided into double layer shell structure and single layer shell structure by the number of layer. The double layer shell structures have a reasonable load transfer and they can provide a larger span than single layer shell structures; but the structures always have too many poles and joints. The design of double layer shell structure is controlled by intensity of its element. The span of single layer shell structure is always short, and the design of this kind of structure is controlled by stability. The intensity of the element of single layer shell structure is small. The form of single layer shell structure is simply and grace.Some scholars have done some researches on partial double layer reticulated shell for the purpose of connecting the advantages of double layer shell structure and single layer shell structures. In this paper, some specified models of Lamella partial double layer lattice shells have been build and optimized, and then, some models of Lamella partial double layer lattice shells with different proportion of the single layer span have been build and Eigen-Buckling analysis to them has been done to find the rule of the change of the stability bearing capacity with the change of proportion of the single layer span. The main work in this paper can be summed as follow:1. Lamella partial double layer lattice shell with the span of 50m has been build by the program MST2008, the area of links were chose through full stressed design, then these models information were read into ANSYS to do Eigen-Buckling analysis furthermore, and then found out the weak part of partial double layer lattice shell. 2. Some special partial double layer lattice shell will be optimized by changing the structure form in the position of the juncture of double and single layer or increasing the area of links, and then, evaluated the performance of partial double layer lattice shell by comparing with double layer lattice shell and single layer lattice shell.3. Eigen-Buckling analysis will be done to partial double layer lattice shells with different value of rise-span ratio and percents of single layer span, and then the change law of the critical buckling coefficient will be obtained.4. Nonlinear analysis will be done to the models of partial double layer lattice shells which have been build before. On one hand, the conclusions which were obtained by Eigen-Buckling analysis will be exam, and the coefficient which can reflect the relation between the two kinds of analysis method will be obtained so, meanwhile, the change of the coefficient with rise-span ratio will be summarized; on the other hand, the effect of geometric imperfection on partial double layer lattice shells will be evaluated.The main conclusions: under the condition of same steel consumption, when the percent of the area of the single layer shell is more than 0.4, the stability bearing capacity of partial double layer lattice shells is close to the stability bearing capacity of single layer lattice shells, but it's far less than the stability bearing capacity of double layer lattice shells. The applicability of partial double layer lattice shells needs to be discussed furthermore.