The influence of reinforcement on fatigue behaviour of a polypropylene composite

In this work the influence of reinforcement (30 wt% 1-mm-long glass fibre, 30 wt% 10-mm-long glass fibre and 42 wt% calcium carbonate) on fatigue behaviour of a polypropylene reinforced composite is investigated. The experimental results show that the high cycle fatigue strength of the polypropylene composite is increased by a factor 3.4 and 2.8 by using 1 mm and 10 mm fibre length, respectively, with respect to 42% calcium carbonate reinforced polypropylene, in terms of applied stress amplitude. However, all experimental results can be synthesised by using the hysteresis energy expended in a unit volume of material per cycle rather than the stress amplitude. Finally the viscoelastic behaviour of 42% calcium carbonate reinforced polypropylene was investigated, showing that the hysteresis energy dissipated in a unit volume of material per cycle due to viscoelasticity is negligible with respect the total plastic strain energy.