An investigation about in use properties of polypropylene fibers used in geotexiles by different methods

Geotextiles, which are the members of technical textiles, are gaining more and more importance in complex applications such as construction sites and agricultural areas by virtue of their many advantages. Geotextiles are exposed to various loads in their application areas so that the knowledge of their mechanical behaviours is a required parameter in the design and production processes and in projects. In this study, a theorical model was constructed by using the raw material and product parameters to predict the mechanical properties of needle punched nonwoven geotextiles, which were produced from staple polypropylene fibers. For this purpose, at first the properties of polypropylene fibers and nonwoven fabrics were analyzed with standard test methods. Then a theoretical model was constructed using theory of layered composite materials and finite element method considering wide-width tensile test of geotextiles. In the analysis of model, two approaches were assumed in consideration with the stress-strain curves of polypropylene fibers and reference fabrics respectively. The nonlinear behaviour of material was taking into account in both of the approaches. Stress analysis of fabrics were performed in commercial finite element programme ANSYS by using experimental and theoretical data. The comparison of theoretical and experimental results indicated that, meaningful stress data can be obtained from the stress distribution of computed models for both of the approaches. However, it was found that the difference between computed and measured elongation was high. The computed elongation values of reference fabric approach were higher then the single-fiber approach values and close to the measured elongation values to some extent. Consequently it can be said that, the model can be used as a tool to ease the selection of raw material and product type, and thus it will provide advantage to the manufacturers in terms of cost and duration of design and production processes.