Fatigue analysis and fatigue reliability of polypropylene/wood flour composites

Fatigue analysis and fatigue reliability of polypropylene (PP)/wood flour (WF) composites were studied. The composites were prepared by incorporating wood flour with and without maleic anhydride and peroxide (MAPO) into cellulose nanofibres impregnated polypropylene. The prepared composites were then characterized by tensile and fatigue analyses. The tensile strength and fatigue life of MAPO mixed composites were lower compared with the composites without MAPO. It was also found that the fatigue experimental data of the composites were widely scattered regardless of the type of composites. Hence, in this study, a fatigue reliability of the composites was sought. Based on the fatigue experimental data, 95% confidence band were created. Since 95% confidence lower band ensure 95% survivability and only 5% failure of the composites, hence, from this study, it is suggested that the fatigue life obtained from 95% confidence lower band can be used as a material reliability index for safe fatigue design of the composites.