A novel technique was introduced in this study to develop damage criteria based on the deformation and fracture behaviour of a single fibre in a thermally bonded nonwoven fabric. Those experiments not only provided insight into damage mechanisms of fibres in thermally bonded nonwovens but also demonstrated a significant drop in magnitudes of failure stress and respective strain in fibres due to the bonding process. Additionally, similar tests were performed on unprocessed fibres, which form the nonwoven. The fibres for the tests were extracted from the nonwoven fabric in a way that a single bond point was attached at both ends of each fibre.
A damage behaviour of the nonwoven fabric is governed by its single-fibre properties, which are obtained by conducting tensile tests over a wide range of strain rates. In this study, polypropylene-based thermally bonded nonwovens manufactured at optimal processing conditions were used as a model system. A finite element (FE) model incorporating mechanical properties related to damage such as maximum stress and strain at failure of fabric’s fibres would be a powerful design and optimisation tool. Understanding mechanical behaviour of these materials, especially related to damage, can aid in design of products containing nonwoven parts.
Thermal bonding is the fastest and the cheapest technique for manufacturing nonwovens.