Material Characterisation of Deflated Structured Fabrics

Structured fabrics are made by interwoven rigid elements that form flexible garments such as chain mail armours. Traditionally, the mechanical properties of these materials were considered fixed. However, recent research has revealed their mechanical properties may be varied. Notably, studies have demonstrated that applying vacuum pressure between layers of 3D-printed chain mails enclosed in a bag induces particle and layer jamming of the elements, thereby affecting the material’s bending modulus. This arises from both compressive frictional forces and the complex geometrical interlocking of the rigid elements. This paper presents a comprehensive set of experimental tests for the characterisation of the stiffness and damping properties with respect to the type and number of fabrics and with respect to the vacuum pressure. More specifically, the study examines experimentally the changes in static properties in response to vacuum pressure changes evaluated on a four- and six-point bending setups. The outcome of this measurement campaign is then reported into the Ashby diagrams to compare the mechanical properties of the in-vacuum structured fabrics with those of classical materials. The potential applications of this research include the development of lightweight adaptive and semi-active vibration mitigation devices.