Micromechanisms of deformation and fracture of polypropylene nonwoven fabrics

Abstract

a b s t r a c tThe micromechanisms of deformation and fracture in tension were analyzed in a commercial polypropylene nonwoven geotextile material in a wide range of strain rates. Two different loading scenarios (smooth and notched specimens) were considered to study how these mechanisms are modified in presence of a stress concentration. The nonwoven fabric presented significant deformability and energy-absorption capability, which decreased with the strain rate, together with a high level of strength, which increased with strain rate. In addition, the material was notch-insensitive as the stress concentration around the crack tip was relieved by marked nonlinear behavior, which induced crack blunting. Different experimental techniques (standard mechanical tests, in situ testing within the scanning electron microscope, digital image correlation, etc.) were used to establish the sequence of deformation and failure processes and to link these micromechanisms with the macroscopic behavior.

Application of digital image correlation at the microscale in fiber-reinforced composites

“…This limitation is due to the presence of strong deformation gradients at the interface between phases, whose evaluation may be compromised by the necessity of averaging displacements and deformations over a certain window. Thus, although DIC is a well-established technique for obtaining the strain fields at the macroscopic scale in composites [2,20,21] and fabrics [9,10,14], this approach has never been used -to the authors' knowledge-at the scale of the fibers due to the differences in stiffness between matrix and fibers.…”

Large deformation of thermally bonded random fibrous networks: microstructural changes and damage

“…The ends of the specimen between the grips with rubber inside were restricted with regard to lateral contraction. The tensile tests were carried out at strain rate of 0.1 s - 1 . Further details about the experimental setup can be found in [21].…”

“…In the last decade, deformation and damage behaviours of nonwoven has received considerable attention. Experimental studies on characterisation of nonwovens are mainly focussed on determination of their performance or the micro-mechanisms involved in their deformation and damage [1][2][3][4][5][6][7][8]. Still, these studies can be hardly used for optimisation of a nonwoven network's structure: through they explained the underlying mechanisms of deformation and damage behaviour they could not quantify fractions of fibres participating in load bearing or evolution of microstructure with fabric's extension, due to limitation of experimental setups.…”

Finite Element Modelling for Tensile Behaviour of Thermally Bonded Nonwoven Fabric

“…Hou et al [2] investigated the effects of random and discontinuous microstructure of the nonwoven fabric on their mechanical properties by incorporating random discontinuous structures representing micro-structures of a real nonwoven material. Ridruejo et al [3] studied the mechanical behaviour and related these behaviours with the property of individual fibre. Gautier et al [4] studied the anisotropic mechanical behaviour of nonwoven geotextiles with tensile test.…”