Anisotropic mechanical behavior of thermally bonded nonwoven fabric

Abstract

Anisotropic properties of thermally bonded nonwoven fabric (polypropylene) have been investigated. Firstly, the orientation distribution function of fibre is obtained by applying Hough transform technique to scanning electron microscopy of nonwoven fabric. Secondly, the influence of specimen width on mechanical behavior of nonwoven fabric has been studied, and the relationships between tensile strength of nonwoven fabric and specimen width are acquired by applying nonlinear fitting. Finally, the anisotropic creep behavior of nonwoven is investigated at different stress levels, different directions of nonwoven and different durations by applying nonlinear fitting, and the empirical model for calculating creep elongation is deduced. The results show that the tensile and creep behaviors of nonwoven fabric are influenced significantly by the fibre distribution. The creep elongation of nonwoven fabric is proportional to the level of loading and time. The creep elongation of nonwoven fabrics follows exponential relationships with time and this is true for all the directions of load and for all the levels of loading.