COMPARISON OF EPOXY CARBON FIBER COMPOSITE LAMINATION IN TERMS OF BENDING STRENGTH AND HARDNESS

Abstract

The purpose of this research is to examine how variations in the number of layers (2, 4, 6, and 8) influence the
outcomes and fiber orientation (0°/90° and 45°/45°) in carbon fiber–epoxy composites on flexural strength and hardness.
Specimens were manufactured using the vacuum bagging method based on ASTM D790 standards, resulting in dense
laminates with minimal voids. The tests were conducted by applying the three-point bending technique to evaluate
flexural strength and the Vickers hardness test to determine surface hardness levels.
The results show that the 45°/45° fiber orientation generally outperforms the 0°/90° orientation. The greatest
resistance to flexural stress value of 1221.29 MPa was obtained from the 45°/45° orientation with 8 layers, while the
lowest value of 467.83 MPa was recorded for the 0°/90° orientation with 2 layers. In the Vickers hardness test, the
highest value of 95.6 HV was also achieved by the 45°/45° orientation with 8 layers, while the lowest value of 78.5 HV
was recorded for the 0°/90° orientation with 2 layers. Overall, increasing layer count led to a notable enhancement in
improved both the strength and hardness of the composite.
Based on these findings, the 45°/45° fiber orientation with more than four layers is recommended for usages
that demand exceptional durability and strong resistance to mechanical stress to multidirectional loads. The vacuum
bagging method proved effective in producing high-quality composites with consistent mechanical properties. It is
anticipated that this research will contribute as a reference in the design process and manufacturing of composites,
particularly in the aerospace, automotive, and other industries requiring lightweight, strong, and durable materials.