Temperature-influenced cutting mechanism of UHMWPE fibres

Ultra-high molecular weight polyethylene (UHMWPE) fibres are the main components of fibre-reinforced composites and fibre concrete, which are polymeric materials with typical temperature sensitivity as the material properties change with temperature or stress changes, and their melting point is as low as 150 °C. Since UHMWPE fibre products are often exposed to ultra-high or low temperature processing environments in practical applications, their fracture failure properties also change significantly. An experimental platform for UHMWPE fibre cutting at different ambient temperatures was built to investigate the effect of the ambient temperature on the cutting fracture behaviour of the UHMWPE fibres by analyzing the cutting-off force, cutting-off depth, cross-section morphology and the ratio of fracture surface expansion/elongation. It presented pressure-induced brittle fracture failure at 0–10 °C and pressure-induced ductile fracture failure from 20 °C to melting point under elastic support, while the tension-induced plastic deformation during the cutting of UHMWPE fibres without support was more significant than the effect of temperature. In addition, a tensile deformation thermomechanics model based on stress-induced melting theory was developed to explain the temperature-influenced fracture mechanism, which was influenced not only by elastic deformation of the material, but also by the heat exchange and stress-induced melting at different ambient temperatures.