Structural Modelling of Knitted Meshes Through an Original Wire Finite Element

The knitted metal mesh is the fundamental component of a Deployable Reflector (DR). The Radio Frequency performance of a DR is profoundly affected by the mesh’s void/filled ratio that change according to the its tensioning. Simulate its behaviour is challenging, inasmuch some nonlinear phenomenon manifest during its loading; just to name a few: the considerable shape change, the huge number of contacts between the wires and the sliding between them. This paper focuses on the geometric nonlinearity. The most used strategies to deal with this type of nonlinearity are discussed, including the analytical and numerical approaches. Finite Element Analysis (FEA) is debated in details, comparing the classic isoparametric approach with a new Wires Finite Element proposed by the authors. This new Element allows to model the mesh with long curvilinear elements, obtaining a considerable gain regarding the required elements number (i.e. less computational effort). The presented numerical comparisons between the proposed Wire Element and the isoparametric ones show similar results regarding the convergence rate, but the proposed element involve many fewer degrees of freedom, i.e. a considerable gain about of absolute time required for the simulation.