Research On Winding Fold Scheme And Unfolding Process Of Planar Origami Structures

Foldable structure has broad application prospect in many fields such as life,military,aerospace and aviation.In this paper,the winding fold structure based on plane origami is introduced into the structural design of spacecraft solar sail.The advantages of this winding fold structure are that it can greatly reduce the volume of the spacecraft,thus reducing the energy consumption.Therefore,the winding structure based on plane origami may be one of the optimal schemes for the future highperformance solar sail system in solar sail spacecraft.In this paper,the research of winding folding structure includes topology design of configuration,determination of rigid mobility,degree of freedom calculation method,simulation analysis of deploying process and design of winding folding configuration considering thickness.In this project,the topology of planar folding structure is systematically studied based on the connection between Miura origami unit and central hub,folding out the corresponding physical model and forming a sample library of winding folding configurations schemes.The constraint equations of typical configurations in the sample library are established,taking the first-order derivative of the constraint equation to obtain Jacobian matrix,and then compute the null space vector of the Jacobian matrix,the dimension of the null space vector is the number of degrees of freedom of the system.For non-rigid origami structures(the number of degrees of freedom is less than zero),the geometric method is used to solve the position solution of the configuration vertices in the process of space motion,and the length change of the crease is obtained,so as to solve the stress change.Finally,a feasible solution is proposed to transform the non-rigid foldable configuration into rigid foldable configuration by adding creases or clipping.Based on the demand of engineering background and engineering of solar sail,several representative winding folding schemes were selected from the winding folding configuration sample library for engineering design,and different winding folding schemes were comprehensively analyzed by using quantitative index including folding ratio,folding times,crease number and crease index;Shape optimization was taken on the edge of membrane of initial winding fold configuration,and then using ABAQUS finite element software to make simulation analysis on the stress,the energy change,roughness index and the effectiveness of the drive mode and the forming situation in the process of unfolding,finally selecting out a winding scheme,and take futher the crease encryption simulation analysis and the driving point encryption simulation analysis,finally,to obtain the influence law of crease encryption and the driving points encryption on the unfolding process.Considering the influence of thickness in the winding folding process of solar sail,the thickness effect is introduced,the zero thickness theoretical derivation formula is modified,and finally the modified geometric design method of winding folding crease scheme considering the influence of thickness is obtained;crease design of solar sail winding folding structure is realized by using programmed language,crease design of solar sail winding folding structure is realized by using programmed language,to obtain the influence law of different geometric feature parameters on unfolding radius,folding radius,folding height of configuration through multiple application examples,further analysis the folding rate difference of different configurations,at the same time,contrast analysis and folding rate differences and the reasons of small curvature crease configuration and large curvature crease configuration,Finally,the small curvature and large curvature winding folding models are manufactured,and experimentally verifing the previous simulation results and program output results.