Research On The Key Technology Of Continuous Forming Of Large Trusses

As an ideal supporting platform for spacecraft structure,large-scale and lightweight space truss structure has been widely used in space missions such as deep space exploration and high-resolution earth observation.It is of great significance to improve the power generation capacity of space solar power station and the sensitivity of space observer.At present,most of the space analysis frames used in orbit are folding mechanisms.In the closed state,there is still a lot of unused space in the mechanism,and the envelope size is limited by the launch space.In contrast,the on orbit construction of space analysis frame has the advantages of smaller launch volume and longer total construction length.Aiming at the continuous forming of large space truss structure,this paper selects fused deposition modeling(FDM)as the manufacturing process of truss structure,and studies its printing materials,the design of truss configuration,the construction of printing machine and the mechanical properties of finished truss structure.Various properties of general printing materials are analyzed through degassing experiments.By comparing the mechanical strength,melting temperature,temperature environment that can work for a long time,whether it will release toxic gas and processing difficulty of printing silk,green materials with high performance such as PLA,PEEK and PEI are selected,and tensile experiments are carried out on similar materials commonly used in the market,Select appropriate materials for later research.By comparing the vertical printer and tilt printer in the market,as well as the printing effect,the tilt printer is selected as FDM forming machine,and the printer structure is built according to the research goal.According to the selected printer structure,through the analysis of the forming route of the truss structure and the selection of the filling route of the printer,the truss structure that can be formed without support is designed.By printing the principle prototype and the designed truss structure,the forming of truss structure with arbitrary length is realized.The bending load performance of the truss structure after ignoring the influence of the web member on the truss section moment of inertia is analyzed.The mechanical properties of the truss structure are verified by the three-point bending experiment of the printed truss structure.