Design And Electromagnetic Characteristics Of Kresling Origami Structure

As a typical origami form,Kresling origami is widely used in space extension arms,antennas,crawling robots and other fields because of its multi-steady state,adjustable stiffness and compression-torsion coupling deformation characteristics.The core of origami structure design is how to depict the position and number of creases on the plane and then fold them into the expected three-dimensional configuration.For Kresling origami structure,the construction of mechanical model,the study of deployment characteristics,the coupling effect of electromagnetic and flow field,and the application of antennas are the key issues to be solved urgently.This dissertation mainly focuses on the mechanical property analysis,the thermal driven development,the electromagnetic characteristics and its coupling with the flow field of Kresling origami structure,which has important theoretical and engineering significance for understanding the mechanical property of Kresling origami structure and promoting the engineering application of origami structure.In order to study the deployment mechanical response characteristics of Kresling origami structure,firstly,the equivalent modulus and critical buckling load during the deployment process are analyzed.Then,the expandability of Kresling origami structure is described in terms of energy and strain.The equivalent mechanical model in the deployment process is established,and the expansibility,multi-steady-state and adjustable stiffness are quantified.Finally,the buckling and vibration characteristics of the Kresling origami structure and its combined structure are studied.In order to obtain the active deformability of Kresling origami structure in the deployment process,and realize the adaptive environment,thermal drive deployment of shape memory polymer origami is studied.The process of folding stage under external load,cooling stage,unloading stage and heat recovery stage(four stages)are obtained,and the mechanical characteristics of each stage has carried on the detailed elaboration,the effects of various parameters on strain and stress during the deployment process are discussed,and the compression-torsion coupling characteristics of the origami structure are analyzed during the rotational deployment process.In order to study the electromagnetic and aerodynamic coupling characteristics of origami structure,firstly,the method of moments is used to study the electromagnetic property of origami structure,monostatic and bistatic radar cross section of metal ball,squat cylinder,dihedral corner and typical structure is analyzed,radar cross sections of Kresling origami structure and other similar structures are calculated.Then,in order to realize the frequency reconfiguration of antenna and improve the bandwidth of the frequency band,Kresling origami antenna with spherical shell on the top is designed.The influence of the metal strip length and instability configurations of different spherical shell on the frequency reconfiguration performance of the antenna in the unfolded and folded states is analyzed,so as to achieve greater frequency reconfiguration and electromagnetic stealth.Secondly,the influence of antenna geometry reconstruction on the electromagnetic field is discussed using multi-port and omnidirectional bending and torsion.Finally,aerodynamic drag and radar cross section reduction during deployment process are studied,and their coupling relationship is evaluated.In order to realize that the origami structure can rotate in a large plane,deploy in a wide range and keep the same frequency,a two-dimensional “Kresling rotational like” origami structure is designed based on the idea of Kresling rotational variant configuration.A spring mechanical model based on a quarter origami cell is established,the deployment mechanical property of the origami structure is predicted,and the snap-through instability characteristics of the cylindrical shell at the crease are obtained.The key factors affecting the deployment characteristics of the origami are obtained by parametric analysis.A microstrip antenna which can rotate and deploy in wide range is designed.The electromagnetic characteristics of the antenna with different configurations are measured experimentally.