Notch Sensitivity on fully Reversed Axial Fatigue Behaviour of Different Polypropylene Compounds

AbstractNowadays recycling is one of the most important keyword to reduce product-costs. In view of this, thermoplastics are very attractive materials for their recycling feasibility. In this paper the static behaviour, the fatigue behaviour and the damage evolution of different polypropylene compounds, characterised by different fractions of recycled material, were investigated. Their fatigue notch sensitivity was analysed as well.Tensile static and fully reversed fatigue tests were carried out on three different material systems, namely a 42 wt% calcium carbonate filled polypropylene (PP), a 42 wt% calcium carbonate filled polypropylene containing 25% recycled PP and a 42 wt% calcium carbonate filled 100% recycled polypropylene. The notch sensitivity was investigated on double-edge notched specimens machined from 5-mm-thick injected moulded plates. Three different notch geometries were analysed, namely a 10mm semicircular notch radius, a 2mm U-notch radius and a 0.5mm V-notch radius. During the experimental tests, the damage evolution was investigated by using an on board travelling microscope. As a result, it was found that all materials are largely notch insensitive in high cycle fatigue