Fatigue and creep behavior of abaca–sisal natural fiber–reinforced polymeric composites

The fatigue and creep behavior of abaca and sisal fiber–reinforced epoxy hybrid composites was investigated for 0°, 45°, and 90° fibers orientations. Long-term prediction with an identical stress level of polymer composite materials is essential for many applications. The life span of stacking natural fiber with polymer varies according to the stacking direction. In this regard, each sample has three layers for each orientation (0°, 45°, and 90°); sisal fibers on the top and bottom layers, and abaca fiber on the middle layer for 0° fiber orientation likewise other two samples were prepared for 45°, and 90° fiber orientation. The samples were fabricated using the hand lay-up method. The testing samples were prepared using abrasive water jet machining. Tension–tension (T-T) fatigue, compression–compression (C-C) fatigue test, flexural creep, and tensile creep tests were performed for the prepared composite materials. T-T and C-C fatigue tests were conducted for the stress level of 0.7 with the fatigue cycles 10,000 for the three different composite materials. Flexural and tensile creep tests were conducted for 20 h at constant stress at room temperature (25 to 27 °C). From the experimental result of the fatigue test, 0° fiber-oriented composite withstands 10,000 fatigue life cycles for stress level 0.7 without any matrix crack failure. Nevertheless, 45°- and 90°-oriented composites have failed at 10,000 and 10 fatigue life cycles for stress level 0.7, respectively. From the C-C fatigue test, no failures occur in the samples up to 10 4 fatigue life cycles due to good stiffness, and minimal plastic deformation has occurred at 50 microns. In the flexural creep test, experimental results show that the creep limit reached 30 min from the test started for three different oriented composites. The fractured surfaces were analyzed with SEM images.