Functionally graded wood filler–recycled polypropylene composite: Effect of mechanical loading on deflection of cantilever beam

Structures made from natural fiber–polypropylene composite material usually have uniform mechanical properties throughout. In some applications, such as in products with snap-fit assembly, it is desirable to have lower stiffness in some parts of the structure while having significantly higher stiffness at other parts of the same structure. In this research, the effect of changing the material arrangement and composition in a cantilever beam made from functionally graded natural filler–recycled polypropylene (FGNF-RPP) composite on the deflection behavior was investigated under static mechanical loads. The composite material was made using 10%, 20%, 30%, and 40% waste wood sawdust as a filler and arranged in different sequences to fabricate beams having 30–40, 20–30–40, and 10–20–30–40 hybrid sections along the length. The deflection behavior was investigated by both experiment and finite element modeling. The results showed that the 30–40 setup produced the least deflection when the 40% end of the beam was fixed, while the 10–20–30–40 setup produced the highest stiffness when fixed at the 40% section. The study has shown that the FGNF-RPP structure can be custom-designed to obtain different stiffness along the same structure, thus making it possible to design products with varying stiffness.