Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : flexural properties


Flexural Properties of Functionally Graded Polymer Alumina Nanoparticles

Mahdi M. S. Shareef; Ahmed N. Al-Khazraji; Samir A. Amin

Engineering and Technology Journal, 2021, Volume 39, Issue 5A, Pages 821-835
DOI: 10.30684/etj.v39i5A.1949

In this paper, a functionally graded polymer nanocomposite (FGPNC) was arranged via mixing the Alumina (Al2O3) nanoparticles (50 – 100 nm) with an epoxy matrix through five layers of 1.2 mm thickness for each layer using hand lay–up technique. Different volume fractions were taken (0, 1, 2, 3 and 4) % of the used nanoparticles and were cast in molds made from acrylic for creating the graded composite sheet in the thickness direction. The prepared isotropic specimen was tested by tensile and compressive test. The results showed that the (4% Vf of Al2O3) has the best enhancement of the ultimate tensile strength (85.25% from neat epoxy) and decreased thereafter. Flexural properties of three different types of functionally graded materials (FGMs), including FGM1, FGM2 and FGM3, isotropic nanocomposite (2% Al2O3) and pristine epoxy were obtained. Flexural strength and flexural modulus of the functionally graded polymer nanocomposite for each type of FGMs enhanced by (51.7%) and (67%), respectively for the FGM1 loaded from the neat epoxy side, whereas for the FGM1 loaded from the (4%) side, the improvement in these properties was (17.8%) and (29.4%), correspondingly over those for the neat epoxy. For FGM2, the improvement in the flexural strength was (27%) and (71.8%) for the flexural modulus as compared with pristine epoxy. The enhancement in the flexural strength of FGM3 was (27%) and flexural modulus (57.7%). Design Modeler (ANSYS Workbench) was used to verify the experimental flexural test results. A very good agreement was found between the experimental and numerical results with a maximum error of (3.92%) in the flexural modulus for FGM1 loaded from the composite side.

Preparation and Study of Flexural Strength and Impact Strength for Hybrid Composite Materials used in Structural Applications

Teeb A. Mohameed; Sihama I. Salih; Wafaa M. Salih

Engineering and Technology Journal, 2020, Volume 38, Issue 8, Pages 1117-1125
DOI: 10.30684/etj.v38i8A.655

Many of the polymeric materials used for structural purposes have weak mechanical properties, these characteristics can therefore be improved by preparing a hybrid laminar composite. In this work use melting mixing method using screw extruder to prepare sheets of polymer blends and nanocomposites based on polymer blends, and using a hot hydraulic press machine to prepared hybrid laminates composites. Two groups of hybrid laminar composites were prepared, the first group is consist of [((94%PP: 5%PMMA: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF] and the second group is [((94%PP: 5%UHMWPE: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF]. The results illustrated the impact strength and fracture toughness are increase with increased weight percentage of Kevlar fiber in for both groups of laminar composites and the highest values for two groups are (58.1, 54.95 KJ/M2) and (8.4, 9.16 MPa√m) respectively, any that, at the rate of increment reached to (120.4%, 107%) and (52.7%, 66.5%) respectively, compared with the neat PP. Moreover, the flexural strength values of the first group samples of hybrid laminar composite remained constant, when added kevlar fiber to nanocomposite. While, the flexural strength values of the second group samples of hybrid laminar composite increase with increase the ratio of kevlar fiber in composite to reach the maximum values (92 MPa) at 8% wt. of kevlar fiber, any, at the rate of increment reached to 39.4% compared with the neat PP. As well as, the results shown that the flexural properties and fracture toughness of the second group samples higher than they are for the first group samples

Study On the Flexural and Impact Properties of Short Okra Natural Fiber Reinforced Epoxy Matrix Composites

Aseel Mahmood Abdullah; Ahmed Mudhafar Hashim

Engineering and Technology Journal, 2012, Volume 30, Issue 10, Pages 1696-1706

The okra natural fiber reinforced epoxy matrix composites were prepared by
hand-lay-up. The weight fractions of okra fiber are (1, 3, 6, 9, and 12% by weight
wt). The flexural properties and impact resistance of composites were determined
by the flexural and impact tests. The maximum modulus of elasticity is (844.93
MPa) at the weight fraction of (12 % wt) of okra fiber, comparison with (91.25
MPa) for virgin epoxy material. The maximum impact energy is (0.75 J) at the
weight fraction of I(12 % wt) of okra fiber, comparison with (0.05 J) for virgin
epoxy material.