Pengaruh Fraksi Volume Face Plate terhadap Kekuatan Impak Komposit Honeycomb Sabut Kelapa

Abstract

The face plate of a sandwich composite receives the impact load first and transfers it to the core, so its proportion within the structure governs how much energy the whole structure can absorb. This study examines the effect of face plate volume fraction on the impact energy and impact strength of a honeycomb composite reinforced with coconut coir fibre. Face plate volume fractions of 30%, 40% and 50% were tested while the honeycomb core fraction was held at 30%. Each specimen combined two 20.1 mm wide, 2 mm thick face plates with two 10 mm high, 2 mm thick cell walls, giving a cross-sectional area of 120.4 mm². Testing followed the Izod method of ASTM D256 on an XJ-300A pendulum tester with a 29.4 J capacity released from 150°, using three specimens per fraction. Mean absorbed energy was 9.80 J at 30%, 15.67 J at 40% and 14.67 J at 50%, giving impact strengths of 0.0814, 0.1301 and 0.1218 J/mm². Raising the fraction from 30% to 40% increased impact strength by 59.9%, while a further rise to 50% reduced it by 6.4%. The relationship is therefore non-linear, and 40% gave the highest value among the fractions tested. One-way analysis of variance gave F(2,6) = 3.51 (p = 0.10), which falls short of significance at the 5% level, so the result is best treated as a strong indication rather than a settled optimum.