Electronic Theses and Dissertation

Penelitian ini bertujuan mengkaji pengaruh metode manufaktur (hand lay-up, vacuum infusion, dan compression molding) terhadap karakteristik penyerapan energi dan perilaku getaran bebas panel komposit. Spesimen menggunakan penguat serat mesocarp kelapa sawit dan matriks resin epoksi dengan fraksi volume tetap 70%:30%. Pengujian karakteristik dilakukan melalui uji impak Charpy (ASTM D6110) dan uji getaran bebas (ASTM E756-05). Hasil uji impak menunjukkan metode vacuum infusion menghasilkan penyerapan energi terbaik sebesar 4,67 Joule (kekuatan impak 58,375 kJ/m²), disusul cetak tekan sebesar 2,67 Joule (33,375 kJ/m²), dan hand lay-up sebesar 1,67 Joule (20,875 kJ/m²). Keunggulan vacuum infusion didukung oleh minimnya cacat porositas (void) dan optimalnya ikatan antarmuka serat matriks. Pada uji getaran bebas, metode cetak tekan menunjukkan frekuensi pribadi tertinggi sebesar 87,04 Hz dengan amplitudo respons 15 g/N, yang mengindikasikan rigiditas struktural statis tertinggi meskipun cenderung lebih getas. Namun, ditinjau dari aspek stabilitas dan disipasi getaran, metode vacuum infusion memberikan performa dinamis terbaik dengan rasio redaman (damping ratio) tertinggi sebesar 0,0354 dan magnifikasi amplitudo resonansi terendah sebesar 14,0 g/N pada frekuensi pribadi 69,12 Hz. Penelitian ini menyimpulkan bahwa metode vacuum infusion merupakan metode manufaktur paling optimal untuk menghasilkan komposit serat mesocarp kelapa sawit dengan kombinasi ketangguhan impak dan kemampuan redaman getaran terbaik.
Kata Kunci: Komposit, Serat Mesocarp Sawit, Resin Epoksi, Hand Lay-Up, Vacuum Infusion, Cetak Tekan, Uji Impak, Getaran Bebas, Damping Ratio.

This study aims to investigate the effect of manufacturing methods (hand lay-up, vacuum infusion, and compression molding) on the energy absorption characteristics and free vibration behavior of composite panels. The specimens utilized oil palm mesocarp fiber reinforcement and an epoxy resin matrix with a fixed volume fraction of 70%:30%. Characterization testing was conducted via the Charpy impak test (ASTM D6110) and the free vibration test (ASTM E756-05). The impak test results showed that the vacuum infusion method yielded the best energy absorption of 4.67 Joules (impak strength of 58.375 kJ/mm²), followed by compression molding at 2.67 Joules (33.375 kJ/mm²), and hand lay-up at 1.67 Joules (20.875 kJ/m²). The superiority of vacuum infusion was supported by the minimal porosity defects (voids) and the optimal fiber-matrix interfacial bonding. In the free vibration test, the compression molding method exhibited the highest natural frequency of 87.04 Hz with a response amplitude of 15 g/N, indicating the highest static structural rigidity despite tending to be more brittle. However, in terms of stability and vibration dissipation, the vacuum infusion method provided the best dynamic performance, achieving the highest damping ratio of 0.0354 and the lowest resonance amplitude magnification of 14.0 g/N at a natural frequency of 69.12 Hz. This study concludes that the vacuum infusion method is the most optimal manufacturing method for producing oil palm mesocarp fiber composites with the best combination of impak toughness and vibration damping capability. Keywords: Composites, Oil Palm Mesocarp Fiber, Epoxy Resin, Hand Lay-Up, Vacuum Infusion, Compression Molding, Impak Test, Free Vibration, Damping Ratio.