Automatic Modeling And Mechanical Analysis Of Typical Warp-knitted Wire Mesh

The warp-knitted wire mesh,as the key composition of the mesh deployable reflector antenna,is laid on the supporting cable net structure to achieve reflecting electromagnetic waves.It is made by ten micron-sized metal wire through a textile process.The loops are hooked,threaded through each other,and changeable in bending.Therefore,the structure is extremely complicated,which brings great difficulties to 3D geometric modeling and mechanical performance analysis.At present,most of the development methods of wire mesh are trial-production at first,which follows the pattern and process of the textile industry.And then the mechanical performance of them are tested to optimize the knitting process.This method takes long development time and often wastes a lot of manpower and costs.As a result,there is an urgent need for a universal method for analyzing the performance of wire mesh,which can directly obtain the accurate mechanical properties of the wire mesh through the initial process selection at the design stage,and guide the adjustment of the later development process.Based on the knitting characteristics of the typical warp-knitted wire mesh,1 through 1 empty two-bar satin wire mesh,the parametric establishment of 3D geometric modeling,the automatic generation of finite element models,and the analysis of its mechanical properties are carried out.And a typical wire mesh mechanical simulation software has been developed.The specific works are as follows:1.A parameterized 3D geometric modeling method for the typical warp-knitted wire mesh is proposed.First,according to the characteristics of the smoothness and periodicity of the wire mesh,the periodic cubic spline curve function was derived to describe the spatial trajectory of the loop central axis in the direction of length with considering the inclination of loops.And the form of cross-section of wires was described with a circle with specific size.And a 3D geometric model of its minimum repeating unit was established.Then,a method of sensitivity matrix adjustment and its optimization model were proposed aiming at the problem of inlaying between wires,and the inlay had been eliminated.Finally,a 3D geometric model of the wire mesh was obtained based on the vector superposition of the minimum repeating unit in the horizontal and vertical directions.This method could realize the automatic establishment of 3D geometric models of typical warp-knitted wire mesh under different process parameters,improve the modeling efficiency,and establish a foundation for the mechanical analysis of wire mesh.2.An automatic FEM modeling and mechanical analysis method for complex wire mesh structure considering highly nonlinear contact factors were proposed.Firstly,the contact form of the wire mesh was analyzed,and based on the several control points of the minimum repeating unit and the sampling points of the periodic cubic spline,the pairs of contact points were obtained.As a result,the adaptive matching of contact pairs of FEM was realized.Based on this,according to the curvature change at different positions of the minimum repeating unit,a curved segmented meshing was carried out to realize the automatic FEM generation and mechanical analysis of the wire mesh.At last,the correctness and effectiveness of the method mentioned were verified by comparing the results of simulation and experiment.3.A simulation software integrating 3D geometric models and mechanical performance analysis of the typical warp-knitted wire mesh had been designed and developed,which is based on some universal softs,C++ Builder,MATLAB and ANSYS.And the software development and technical difficulties,the interface operation of each module and specific functions was detailed.At last,the functionality of the software was verified through an example.