Abstract :
he innovation in the field of composite materials requires the creation
of materials with optimal resistance to bending. One of them is to use natural
fiber as an alternative to replacing fiberglass. The natural fiber composite
material has almost the same flexural strength as synthetic fiber composites. The
advantage of natural seats is that they have a high cellulose content which is
suitable when linked by polymers.
The purpose of this study was to identify the effects of variations in the
length of ramie fibers on the flexural strength of polyester composites. The
material used was ramie fiber with the Yukalac 157 BQTN-EN polyester resin
matrix. The method used was manual lay-up. Composites used a discontinuous
direction of the fibers, the volume fraction of the composite fibers as 15% and 5%
of alkaline quenching (NaOH) with variations in fiber lengths of 10 mm, 20 mm
and 30 mm. The test was carried out by bending test with bending test pieces
according to standard ASTM D 790-03.
From the composite flex test, the flex prices on the variation of the fiber
lengths of 10 mm, 20 mm and 30 mm gave the results of 106,752 MPa, 119,863
MPa and 124,353 MPa. The highest bend test result on the variation in fiber
length of 30 mm was 124,353 MPa and the lowest was on the variation in fiber
length of 10 mm as 106,752 MPa. The bending test showed that the variations in
fiber length had effects on the flexural strength, the longer the fiber, the higher the
flexural strength value.