Theoretical Analysis And Experimental Study Of Self-driven Folding Structures

In recent years,the application of the deployable structure and smart material have been increased.The research which is the paper presented is to drive the self-folding structure by shape memory alloy,and then it is guaranteed that the programme is controlled.This kind of structure can be used in many ways,such as civil engineering(retractable roof),aviation(deployable wing)and spaceflight(foldable antenna).(1)This paper analyzes the driving path of folding process of single vertex and four fold origami model,and the folding model of six fold was analyzed under the condition of considering symmetric motion control constraints.The basic properties of shape memory alloy wire were determined by phase change temperature test,tensile test,residual strain test and recovery force test on shape memory alloy wire.Finally,the axial strain response of the shape memory alloy wire is used to perform the drive analysis between the two thickness flaps.(2)Finite element analysis and experimental research were carried out on the crease property of metal materials.The conventional origami model has no stiffness in the ideal state,so it is uncontrollable to its drive.When a certain stiffness is applied to the crease,the folding/unfolding process can be controlled by force or energy.The folding effects of different creases were compared and evaluated by the relative folding indexes presented in this paper.According to the evaluation results,the appropriate crease form is selected to be applied to the special four fold model--Miura origami model.This paper expounds the correlation between the driving energy and the degree of folding,and analyzes the necessary driving force and the required driving energy when different models are folded at a specific angle.(3)Considering the exterior deformation of the component when folding,an intelligent system of real-time monitoring and automatic adjusting for exterior deformation of the component is attempted.Using the fiber Bragg grating and shape memory alloy as sensors and actuators respectively,by applying the classical plate-shell theory inversely,the shape function of the strain and deflection on the plane coordinates of the component is calculated when the opposite side is clamped.For the adaptive array,a complete set of accuracy correction system is summarized.