Document Type : Research Article
Abstract
Natural fibers have economic and environmental advantages, offering attractive alternatives for different applications such as automotive parts, door inserts, dashboards, seats, etc. In this research, the flexural properties (using 3 point bending test), S-N curve and endurance limit values were evaluated for composite materials. The blend contains 90% epoxy and 10% polyurethane by the weight fraction was used as matrix, cotton, jute and silk natural woven fibers were used as reinforcement, which was laminated by 0/90 and by a combination of 0/90 and 45/-45 Angle orientation for each type reinforcement. Then, the cotton layers were hybridized by three types of arrangement, which include: cross interfering between jute woven and unidirectional flax fiber as interplay (JF) woven (HCajf), short fibers of jute and silk distributed randomly (HCajs) and silk woven (HCas). A vacuum infusion system (VIS) was used to prepare the sample. SEM was used to investigate the characterization of microscopy images. The evaluated results showed that the mechanical properties, fatigue life and endurance limit value of a composite laminated with 0/90 Angle orientation is higher than the composites laminated by a combination arrangement of 0/90 and 45/-45 Angle orientation. Hybridization of the cotton composites by three-type arrangement (HCajf, HCajs and HCas) improved the mechanical properties, fatigue life and endurance limit increased by 38.229 %, 21.017 % and 6.303 %, respectively, the hybridization with natural silk fiber has a significant effect on the mechanical properties and ductility of the composite material. SEM tests for fatigue samples detected several types of damage mechanisms related together, which caused degradations growing on different scales.
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