Study On The Roof Strcuture Of The Large-span Reticulated Mega Hangar

The structure of the hangar roof has the unique characteristics which is different from the ordinary spatial structure.In order to meet the requirements of storage and maintenance of large aircraft,the span of the structure of the hangar roof should be as large as possible.Height of the hangar roof structure is resticted by the obstacle free airspace,and in order to meet the requirements forstoring the large aircraft,the hangar roof needs a free height.Therefore,the hangar roof thickness should be as small as possible to meet the requirements for height of the hangar inside and outside;In order to facilitate the free movement of the aircraft,we can not set column and other supporting member on the door.The large span roof of hangar is usually nothing but three sides supporting structure.Due to the above features,the hangar roof structure requires that the span is as large as possible,the thickness is as small as possible,and the rigidity is as strong as possible.The traditional flat grid structure has higher thickness to meet the requirements of span.The height of the reticulated shell structure and flexible space structure can not meet the requirements of airport clearance.With our country is continuously striding forward from large aviation industry to power one,more and more large aircrafts are put into use.And in order to meet the actual requirements for concurrently maintaining many large aircraft in the hangar,it is urgent to study a new type of spatial structure with smaller thickness and larger stiffness and larger span.In this paper,a new mega grid structure-three-direction grid prestressed large grid structure is proposed.The geometric configuration of the structure is based on the evacuated plane grid.Use the lattice combined bar to replace the single member of the post space truss,retain the bar on the main stress path and remove the bar on the secondary stress path.Then,the geometric formula of the three-direction grid prestressed mega grid structure is derived.Finally,use the Grasshopper plug-in of Rhino software to develop 5 modules that parameterize the three-direction grid prestressed maga-grid structure.Based on the nonlinear finite element analysis method of the cable element,in this paper we find the shape analysis of the three-way grid prestressed large grid structure.Total steel quantity as the objective function to structure,with the method of single variable,prestress level,long span ratio and the giant component internode number grid is variable parametric analysis,to explore different prestress level,long span ratio and different number of the giant component internode grid that several parameters of the structure under static performance and dynamic performance.The results show that the introduction of prestressed cable can not only improve the mechanical properties of the structure,but also reduce the steel amount of the structure.We analyzed several different nodes types of three-direction grid type prestressed mega-grid structures.The cable and pole,nodes that connect the prestressed cables and members at the same time and ensure that the cable can slide freely can be selected.The finite element numerical model and the scale model test were used to study the force performance of the joints under different load conditions.The results show that the finite element calculation and test results in line with the good,the finite element calculation of cable-strut node under maximum test load does not exceed the elastic,the maximum stress value under the design load and test scale values quite close.