Parametric Design And Stability Analysis Of Rotating Paraboloid Reticulated Shell

Reticulated shell is a kind of space grid structure similar to that of the rack, the structure is based on the bar,and through the connection of grid nodes according to certain rules, and then press shell structure decorate space frame. Reticulated shell with colorful architectural form and the superior mechanical properties, and the span is larger, more and more widely applied in modern architecture design.In this paper, the research target is single-layer paraboloid of revolution reticulated shell, the structure is positive gaussian curvature reticulated shell,it can form the internal force of the closed system and it can also offset the internal force between link.It can be used for various sports venues, concert halls, etc.And the appearance is beautiful and smooth,and the structure form is novel, can build the dome of Islamic architecture style of the big rise reticulated shell, so as to meet the construction requirements. The main work of the article includes:(1) According to the rotating parabolic equation which is Z=(-4f/S2)(x2+y2)+f and the proportional coefficient of t=(Nx-i)/(Nx-0.5), reference characteristics of grid partitioning which belongs to the six kinds of typical spherical reticulated shell,the application of APDL (ANSYS Parametric Design Language) to develop five kinds of single rotating paraboloid reticulated shell parametric design method and corresponding macro program which of the grid types are rib ring, schwedlerr, Kiewitt, union square, three to the grid,and the length of the links which of every circle are relatively uniform.Designer can easily and quickly make the five different types of reticulated revolving paraboloidal shell model which just input S,f, Kn, Nx.(2) According to the spatial distance formula at two points, using the formula of each node combine net shell macro parameters (S, f, Kn, Nx) and micro parameters (the grid shape and size,the Angle bar,length of rods, etc.)to bulid the macro and micro geometric parameter geometric parameter mathematical model.Take rib ring rotating paraboloid reticulated shell for example,in the radial pole pieces of equal length,set up on the net shell structure function relation about the high vector f, which is f=s(?),i=2,3,4...,Nx. And having gotten the choosing range of f,thereby significantly reduce the amount of calculation and improve the working efficiency.(3) Using ANSYS carried on the static performance analysis to the five single rotating paraboloid reticulated shell,researth the mechanical characteristics of the five kinds of net shell model. And respectively explores S, rise span ratio, Kn, Nx turns to the static performance of the network shel.This design provide the theoretical basis for the designers of how to choose span, high vector and grid number can make net shell taking the mechanical characteristics better.(4) Using sequence two-stage optimization algorithm, select two reticulated shell models with total structure of steel consumption as objective function and design variables for grid number(Kn, Nx) to make shape optimization. Depth and detailed analysis of the changing rule of steel consumption of the structure with the number of grid and the rise-span ratio and span changes.And had gotten the optimal numbers of the grid with the least steel consumption for one span and one rise-span ratio. In the division of the department as a practical engineering guarantee strength, stiffness and stability with how to select grid numbers to reduce the net shell of steel consumption,and reduce the cost of project provides certain theoretical basis.(5)Using ANSYS do eigen-buckling analysis and considering the initial defect of geometric nonlinear buckling analysis for rotating paraboloid reticulated shell,extracting the first three order buckling mode and the first six order buckling eigenvalues under six cases of rise-span ratio,analyzing the whole instability process of the shell and the buckling characteristic value changing with the rise-span ratio.considering two cases of the initial defect,extract ultimate load under six cases of rise-span ratio of shell,drawing the load displacement curve,analyzing the effects of initial defects on the stability of the reticulated shell.