Dynamic thermo-mechanical and impact properties of helical auxetic yarns
Composites Part B: Engineering
This is the final version of the article. Available from Elsevier via the DOI in this record.
This paper presents an experimental investigation of the dynamic thermo-mechanical and impact properties of helical auxetic yarns (HAYs). A series of thermoplastic polyurethane (TPU) core fibres fabricated using an extrusion process have been wrapped with either ultra-high-molecular-weight polyethylene (UHMWPE) wrap or stainless steel wire wrap to form helical auxetic yarns. Dynamic mechanical analysis (DMA) measurements indicated that the core/wrap diameter ratio and the initial wrap angle influenced significantly the dynamic thermo-mechanical behaviour of HAYs. The impact test results have shown that the fibre property, impact velocity and the initial wrap angle had great effect on the impact response of a HAY. Importantly, in this work it is shown that an optimal wrap angle can be found to give the best combination of stiffness, energy absorption and auxetic performance of HAYs.
This work is supported by the UK Engineering and Physical Science Research Council (EPSRC grant No. EP/J004553/1). The authors would like also to acknowledge their colleagues Yat-Tarng Shyng and the late Dave Baker for technical support.
Composites Part B: Engineering, 2016, Volume 99, p.494-505