PENGARUH SUSUNAN PADA KOMPOSIT LAMINAT SERAT SABUT KELAPA TERHADAP KEKUATAN BENDING DAN KETANGGUHAN IMPAK

Abstract

Natural fibers have emerged as promising reinforcement materials in composite applications due to their abundance, low density, and favorable specific strength. Composites reinforced with natural fibers are not only environmentally friendly but also demonstrate improved mechanical properties and energy absorption capabilities, making them suitable as alternative structural materials. The stacking sequence and fiber orientation have been shown to significantly affect the flexural and impact performance of laminated composites. This study aims to investigate the effect of different stacking sequences on the flexural and impact properties of laminated composites reinforced with coconut coir fibers. The composites were fabricated using woven and randomly oriented coconut fibers that were alkali-treated with 5% NaOH for 2 hours and dried at 80°C for 3 hours. Unsaturated polyester resin with MEPOXE catalyst served as the matrix, and the hand lay-up method was used for fabrication. Three stacking variations were examined: woven–woven–woven, woven–random–woven, and random–woven–random. Flexural testing was conducted according to ASTM D790, while impact testing followed the Charpy method based on ASTM D6110. The results showed that the woven–woven–woven configuration produced the highest flexural strength of 41.23 MPa. Meanwhile, the random–woven–random configuration exhibited the highest energy absorption and impact toughness, reaching 2.84 J and 0.0295 J/mm², respectively. These findings confirm that woven layers contribute to superior flexural strength, while random fiber arrangements on the outer surfaces enhance energy absorption. Therefore, the stacking sequence plays a crucial role in determining the mechanical performance of coconut coir fiber-reinforced laminated composites.