A three-dimensional (3D) Monte Carlo model is developed to study the fiber curliness effect on the percolation threshold of a composite filled with electrically conductive curved fibers. These fibers are simulated as zigzag-shaped fibers that are randomly positioned in the composite, forming a 3D random network. The simulation results show that the fiber curliness can significantly affect the percolation threshold: the more curved the fibers, the higher the threshold. The results also reveal an exponential relationship between the threshold and the fiber aspect ratio: the higher the aspect ratio, the lower the threshold. These predicted trends agree well with existing experimental and simulation results based on straight fibers or curved fibers with simpler shapes.

Oil palm ash (OPA) is an agro-industry waste and it has disposable problems. In the present study, an effort was made for value addition to OPA by incorporating it as a micro-filler in different concentration (0, 10, 20, 30, 40, and 50%) and sizes (100, 200, and 300 mesh size particles) in the epoxy matrix. Prepared micro OPA was having a crystallinity index of 65.4%, high inorganic elements, and smooth surface morphology. Fabricated composites had higher void content as compared to neat epoxy matrix. Mechanical properties of fabricated composites had a maximum value at 30% loading of 300 mesh-size filler due to its low void content and size as compared to filler of 100 and 200 mesh size. Further increase in the concentration of OPA filler after 30 wt% of loading leads to the agglomeration of OPA microparticles and thereby resulted in the reduction of mechanical characteristics such as tensile strength, tensile modulus, flexural strength and flexural modulus of the composites. However, elongation at break decreased with increase in filler content at all percentage. Thermal stability and char residue percentage of composite increased with the concentration of filler at all percentage. Surface morphology of composite showed that OPA incorporation lead towards its roughness and cracks were originated from the site of OPA embedded in the epoxy matrix. The 300 meshsize particles were having the best effect on composite as compared to 100 and 200 mesh-size filler.