Papers by Keyword: Bonding Point

Abstract: This study derives the stress field of the bond rolling of unbounded sandwich sheet with outer soft and inner hard layers at the roll gap considering Coulomb friction between the roll and the sandwich, and Coulomb friction at the interface of the unbounded region. Due to the sandwich sheet unbounded before rolling, three-layer sheets are not bonded firmly. The neutral point between the roll and the sandwich sheet, the rolling pressure distribution along contact interface between the roll and sandwich sheet, the horizontal stress of whole sandwich sheet, the horizontal stresses in the component layers of sandwich, the shear stress at the interface of sandwich sheet, the rolling force, and rolling torque, etc. are effectively calculated via this model. Furthermore, it is of great important to obtain the bonding point at the interface and the thickness ratio of sandwich sheet at the exit from this study. Additionally, the bonding conditions of the unbounded sandwich sheet are found to avoid the failure in bond rolling. This study proposed is suitable for the on-line bond rolling; it offers useful knowledge to conduct the experimental bonding conditions.

Abstract: Nonwoven fabrics are web structures of randomly-oriented fibres, bonded by means of mechanical, thermal or chemical techniques. This paper focuses on nonwovens manufactured with polymer-based fibres and bonded thermally. During thermal bonding of such fibres, as a hot calender with an engraved pattern contacts the fibre web, bond spots are formed by melting of the polymer material. As a result of this bonding process, a pattern of bond points connected with randomly oriented polymer-based fibres form the nonwoven web. Due to their manufacturing-induced composite microstructure and random orientation of fibres, nonwovens demonstrate a complex mechanical behaviour. Two distinct modelling approaches were introduced to simulate the non-trivial mechanical response of thermally bonded nonwovens based on their planar density. The first modelling approach was developed to simulate the mechanical behaviour of high-density nonwovens, and the respective fabric was modelled with shell elements with thicknesses identical to those of the bond points and the fibre matrix having distinct anisotropic mechanical properties. Random orientation of individual fibres was introduced into the model in terms of the orientation distribution function in order to determine the material’s anisotropy. The second modelling approach was introduced to simulate low-density nonwovens, and it treated the nonwoven media as a structure composed of fibres acting as truss links between bond points.