Mechanical performance and energy absorption characteristics of sustainable bio-based luffa/woven carbon fabric hybrid epoxy composites

Mechanical behavior was tested for hybrid composites with natural luffa fiber and artificial woven carbon fabrics within an epoxy matrix with orientation angles of [90°], [45°], and [0/90°]. Specimens were produced with artificial and natural fibers in a four-layer configuration. Three-point bending, tensile, and low-speed impact tests were applied. In tensile tests, specimen [0/90º Carbon – Luffa – Luffa – 0/90º Carbon] exhibited the highest strength, reaching approximately 42 MPa. In three-point bending tests, specimen [0/90º Carbon – Luffa – Luffa – 0/90º Carbon] showed the highest force of approximately 120 N. In low-speed impact tests, at an impact energy of 5 J, the impactor rebounded without penetrating any of the specimens. At an impact energy of 15 J, punctures and fiber damage occurred in samples [90º Carbon – Luffa – Luffa – 90º Carbon] and [45º Carbon – Luffa – Luffa – 45º Carbon]. In contrast, sample [0/90º Carbon – Luffa – Luffa – 0/90º Carbon] reached maximum force values of approximately 6000 N at 15 J impact energy and approximately 3500 N at 5 J impact energy, exhibiting higher impact resistance without puncture. Based on these results, the woven carbon fabric orientation angle had a decisive effect on the bending, tensile, and impact behavior of hybrid composites.