This study investigates the effect of hybridization on tensile strength of woven fabric glass/epoxy composite laminates with two different notch sizes of 5 mm and 10 mm. Tensile tests are performed on notched [0 /90 ] 3s specimens of woven fabric C-glass/ epoxy composite laminates and their hybrid reinforced with woven fabric 3K-carbon layers in order to measure tensile strength and characterize damage mechanisms. The results suggest that hybridization has a considerable effect on the improvement of the tensile strength of C-glass/epoxy composite laminates but also has reduced the rupture strain of the composites. Microscopic observation of specimens after tensile loading reveals the existence of transverse and longitudinal cracks, delamination and transverse fiber damage in hybrid composite laminates.
This paper discusses the aerodynamics behavior of a baseline design of a Blended Wing Body (BWB) aircraft developed at MARA University of Technology (UiTM). Two methods of analysis are presented, i.e. Steady-state, three-dimensional Computational Fluid Dynamics (CFD) of the BWB at Mach 0.3 and Wind Tunnel experiments on 1/6 scaled half model of the BWB at Mach 0.1. In both methods of analysis, Lift Coefficient (CL), Drag Coefficient (CD) and Pitching Moment Coefficient (CM) are measured and compared at respective Mach numbers with respect to variation of angle of attack. Pressure contours and Mach number contours are plotted and the turbulence area is predicted, both extracted from CFD analysis. Visualization using mini tuft during wind tunnel tests is also executed to complete the analysis where the stall progression patterns can be clearly observed. The presented BWB UAV design here has achieved an unprecedented capability in terms of sustainability of flight at high angle of attack, low parasite drag coefficient and decent maximum lift coefficient. Some recommendations for future improvement of the BWB are given.
Effects of matrix modification using liquid epoxidized natural rubber (LENR) on the mechanical behavior of short CFreinforced epoxy composite were investigated in this study. Composite samples were prepared in four different concentrations: 3, 5, 7, and 10 wt% fiber fractions. Flexural and fracture toughness tests were performed to observe the mechanical behavior of the samples. LENR improved the mechanical properties due to the plasticizing effect of rubber particles which increased the flexibility and led to a higher debonding strength. The results showed that the treated carbon had improved the flexural strength and flexural modulus by 77% and 21.8% at 7 wt% fiber loadings, respectively, while fracture toughness increased by 15% at 10 wt% fiber loadings compared to the neat epoxy.
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