Notch effects and crack propagation analysis on kenaf/polypropylene nonwoven composites

This paper has studied the open-hole and pin filled-hole effects on the tensile properties of Kenaf/Polypropylene Nonwoven Composites (KPNCs) in production of automotive interior parts. The influence of specimen width-to-hole diameter (W/D) ratios of 6, 3, and 2 on failure load was studied. Two sample thicknesses of 3 mm and 6 mm were evaluated. Mechanical properties of the KPNCs in terms of uniaxial tensile, open-hole tensile (OHT), and pin filled-hole tensile (FHT) were measured experimentally. A preliminary model by extended finite element method (XFEM) was established to predict the failure load and simulate crack propagation of 3 mm thick open-hole and pin filled-hole specimens. Good agreement was found between experimental and simulation results. By calculating the stress concentration factor Kt for brittle materials, the net section stress factor Kn for ductile materials, and the strength reduction factor Kr, it was found that KPNC was relatively ductile and insensitive to the notch.