Mechanical behaviour of composite artificial tendons and ligaments

The mechanical behaviour of a soft composite material based on a hydrogel polymer matrix reinforced with bundles of poly(ethylene terephthalate) (PET) fibres is analysed. The composite reproduces the typical J-shaped stress-strain curves displayed by natural tendons and ligaments. The lamination composite theory was used to investigate the role of the fibres and the matrix properties, as well as the role of the winding angle and the volumetric fraction of fibres, on the mechanical response of this system. The results suggested that large variations in the mechanical behaviour can be obtained by changing the winding angle of the fibres in the composite which determines the extent of the ‘toe’ region and the sensitivity of the system to the rigidity of the fibres.