Mechanical analysis of hybrid textiles with thin NiTi wire

Hybrid textile structures composed by polyamide (PA), Lycra (EL) and NiTi thin wires were manufactured. The fabrics were realized by knitting EL as weft and warp filaments and a coupled PA/NiTi through in-laying technique.

Superelastic NiTi wire with diameter of 50 microns in both straight annealed and snake like form were used. The polyamide filament used coupled with the NiTi wire has a diameter around 140 microns, while the textile structure is composed by various Lycra filaments, characterized by different diameters.

The textile structures were realized by a circular machine appropriately equipped and used in order to minimize problems related to the use of the thin NiTi alloy filament.

To study the influence of NiTi filaments on mechanical properties specimens taken from textile fabric were analysed by using a DMA Q800 TA Instruments equipped with a tension film clamp. Stress/strain measurements were carried out on fabrics with and without NiTi filaments, up to 300% in elongation. Superelastic NiTi filament enhances the textile stiffness without reducing elastic performance of the hybrid structures.