Pengaruh tebal core kayu sengon laut terhadap kekauan panel komposit sandwich berpenguat serat kenaf oleh beban lengkung dinamis

IRFA'I, Mochamad Arif, Prof. Ir. Jamasri, Ph.D

2008 | Tesis | S2 Teknik Mesin

Tujuan penelitian ini adalah menyelidiki pengaruh tebal core terhadap penurunan kekakuan komposit sandwich kombinasi serat kenaf acak dan anyam bermatrik poliester dengan core kayu sengon laut. Material yang digunakan adalah serat kenaf (acak dan anyam), kayu sengon laut, resin unsaturated Poliester 157 BQTN (UPRs) dan Hardener MEKPO. Komposit dibuat dengan metode cetak tekan. Komposit sandwich tersusun dari dua lamina komposit dengan core ditengahnya. Lamina komposit terdiri dari 3 mat serat kenaf (acak-anyam-acak) dengan fraksi volume serat 35%. Core yang digunakan adalah kayu sengon laut yang dipotong pada arah melintang dengan variasi ketebalan 5, 10, 15 dan 20 mm. Pengujian dilakukan dengan bending dinamis dan pada siklus tertentu dicatat kenaikan defleksinya. Penurunan kekakuan bending ditentukan dengan perbandingan nilai momen dan defleksi. Spesimen dan prosedur pengujian bending mengacu pada standar ASTM C393. Hasil penelitian menunjukkan bahwa kekakuan bending menurun seiring bertambahnya jumlah siklus beban uji dinamis. Hal ini terlihat dari nilai tebal core momen / defleksi berkurang seiring bertambahnya siklus beban uji dinamis. Persentase penurunan kekakuan masing-masing komposit sandwich adalah 25,18%, 16,93%, 12,89% dan 10,12% untuk tebal core 5 mm, 10 mm, 15 mm dan 20 mm, berturut-turut. Persentase penurunan kekakuan terendah pada komposit sandwich tebal core 20 mm yakni 10,12%, sedangkan persentase penurunan kekakuan terbesar pada komposit sandwich tebal core 5 mm yakni 25,18%,

This study aims to investigate the effect of core thickness to the stiffness degradation of the sandwich composite, prepared by random-woven kenaf fibers, poliester, albizzia wood core and MEKPO hardener. The Sandwich composite was made using a press mold method. The composite is constructed from two faces laminate with core in the middle of the laminate. The laminate composite was made from 3 layer of kenaf fiber (random-woven-random) for 35% of fiber volume fraction. The core used is albizzia wood which was cut in cross section direction for 5, 10, 15 and 20 mm of core thickness variation. The test was carried out by dynamic bending load to observe the increasing of deflection. The degradation of bending stiffness has been determined by using the comparison value of moment and deflection. The specimen and bending test procedure were related according to ASTM C 393. The result shows that the bending stiffness decreases with the increasing number of cycles of the dynamic bending load. It shows that the value of core thickness moment / deflection decreases with the increasing number of cycles of the dynamic bending load.The percentage of stiffness degradation of the sandwich composite is 25,18%, 16,93%, 12,89% and 10,12% for core thickness 5 mm, 10 mm, 15 mm and 20 mm respectively. The lowest percentage of stiffness degradation of the sandwich composite with 20 mm of core thickness is 10,12%., while the highest percentage of stiffness degradation of the sandwich composite with 5 mm of core thickness is 25,18%.

Kata Kunci : Tebal core,Komposit sandwich,Kekakuan,Bending dinamis, sandwich composites, stiffness, core thickness, dynamic bending