Abstract
In thermobonded nonwovens, the design of the bond point geometry is of major importance to the desired mechanical behavior. Despite the geometry's significance the selection is subject to a trial and error approach.
This paper describes a numerical method for the prediction of the nonwovens tensile behavior depending on the bond point geometry and process parameters.
The tensile behavior of thermobonded nonwovens is modeled in a numerical model using the Finite Element Method (FEM). The approach covers the influence of the shape and size of the bonded area as well as the properties of the non-woven. The influence of the technological parameters during the bonding process such as process temperature and pressure, are also covered.
The solidified area within the bond point is represented using solid elements. The connection between the bonded areas is modeled using link elements, representing the connecting fibers. This approach covers the nonlinear behavior caused by the fiber material properties and geometry. Sets of fibers are combined into fiber bundles in order to reduce the numerical effort. The fiber orientation within the nonwoven is taken into account in order to represent the different fiber distributions caused by the nonwovens production techniques.
The mechanical properties of fibers and fiber bundles are taken from experimental data and are mapped onto the model. The model is verified using experimental data from tensile testing.