Characteristic load-elongation behavior of weak electrospun fiber texture

The main purpose of this research is to establish the characteristic load-displacement behavior of weak, planar, randomly oriented fiber bundles. In this paper unidirectional strain-controlled force measurements have been performed on brittle, randomly oriented fibrous scaffold, prepared by electrospinning from polysuccinimide (PSI) based polymers. We observed that the mechanical behavior of these weak 2D networks deviated significantly from that of traditional materials treated usually within the framework of continuum mechanics. These loading curves show a maximum type dependence due to damage formation that results in stiffness reduction at elongation. We are able to monitor the rupture formation by sensitive force measurements and study how evolution of the ruptures develops during elongation. On the basis of the Fiber Bundle Model, the loading force can be directly related to the cumulative probability distribution function of failures, appearing on the loading curve as abrupt force drops during extension. We are able to determine the sequence of rupture force during extension as well as the magnitude of force drops. Large number of failures observed on each loading curve, made possible to analyze the statistical properties of damage formation. We estimated the cumulative empirical distribution function of rupture force and analyzed them on the basis of Weibull distribution. The shape parameter of distribution proves that, the rupture force of polysuccinimide electrospun fiber bundles follows the exponential distribution function. This experimental technique can provide the initial stiffness, as well as to explain load bearing capacity of several synthetic and biological textures that are composed of fibers. It also suggests improved probabilistic approaches to the development of more sophisticated statistical models.