Drilling Parameters and Post-Drilling Residual Tensile Properties of Natural-Fiber-Reinforced Composites: A Review

Abstract

This review highlights the influence of parameters on the drilling characteristics of biocomposites including natural fibers. The particular structure of natural fibers, including their hierarchized geometry, which potentially causes fibrillation, can result in an increased chance of irregularity of the hole and a more complex mode of delamination or, in general terms, damage to the composite. On the other hand, to attain an effective junction of the laminates in a structure, a nut–bolt procedure must be selected, which requires the performance of a drilling operation. This is becoming increasingly important since the fields of application for natural fibers and their variety have been steadily growing in the last few decades. Additionally, adequately performed drilling operations can address considerations related to circular economy. The drilling characteristics evaluated herein include thrust force, torque, surface roughness, and the delamination factor at the entry and exit of the drilling tool. The variation in tensile strength, stiffness, and strain propagation due to the presence of open holes of various sizes, the number of holes, the holes’ patterns, the effect of the type of fiber of the notches, the fiber architecture, and the fibers’ stacking sequence in biocomposites have also been discussed.

Mechanical, morphological and wear resistance of natural fiber / glass fiber-based polymer composites

“…Figure 11 a) shows that untreated 10 wt% AF/10 wt% GF observed higher fiber breakages and matrix cracks in comparison to NaOH treated natural fibers (11 b). The same percentages of decline in the wear resistance of natural fiber epoxy-based composites were observed (Goutham et al 2023;Arivendan et al 2024). The combination with 20 wt% AF/20 wt% GF exhibited greater distribution of fibers in the matrix with better fiber/resin compatibility in NaOH treated natural fibers 11d than untreated fibers 11c.…”

“…5a). The impact strength results showed better improvement with the hybrid fiber mixing and alkali treatment with natural fibers (Rajeshkumar 2021;Goutham et al 2023). The overall fiber incorporation from 20 to 40 wt% observed better properties.…”

Extraction and characterization of fiber from the flower stalk of Sansevieria cylindrica

“…Roughness measurements may also prove of interest in future exploitation of the superhydrophobic characteristics of Sansevieria fibers, as reported by Mohd Aref et al (2023). This is especially important for some types of applications related to the automotive industry, such as for use in brake pads, a function that has been proposed for a number of natural fibers, as per a recent review (Ammar et al 2023;Goutham et al 2023). In the particular case of Sansevieria, the structure of the stem appears of particular interest for this specific application due to the strength and roughness of the short fibers extracted, as shown in Sansevieria ehrenbergii (Srinivasan et al 2020).…”