The numerical analysis of mechanical properties of fibrous network structures with negative Poisson's ratio (auxetic) according to various parameters

One of the parameteres governing mechanical properties of materials is Poisson's ratio. Poisson's ratio is quantitative expression of physical change at an elastic material resulting from an applied axial load to the material. Today, commonly-used engineering materials' Poisson's ratio have different values in the range of 0 and 0.5. It can be clearly observed that for a material having a Poisson's ratio in this range of value, in case of applying an axial tension stress (or compression), there occurs contraction/expansion in transverse direction while an elongation/ a shortening occurs in longitundinal direction dueto tension/compression. Besides, as results of investigations and studies have been carried on for 30 years, a new class of materials was discovered which react extraordinarily against to external effects (axial loads etc.) in contrast to conventional materials. This class of materials called 'auxetic' (materials which have negative Poisson's ratio). In this study, numerical analysis and investigation of mechanical properties of auxetic fibrous network structures according to various parameters. Numerical 2 dimensional conventional fibrous network structure models generated by using MATLAB®, then imported into ANSYS® program for performing deformation analysis. Effect of parameters were investigated over auxetic fibrous network structures' Poisson's ratio and effective Young's modulus with analyses performed for the different values of the parameters; one of which is notably, axial compression (compress in –y direction) having the most important role in converting conventional fibrous network structures to auxetic one, also fibers' orientation angle in x-y plane and aspect ratio of fibers that effect the qualitative and quantitative situations of auxeticity directly, and results were submitted.