Mechanical Properties Investigation of Composite Material Under Different Parameters Variations

Abstract

The main objective of this research is to design and select a composite plate to be used in fabricating wing skins of light unman air vehicle (UAV). The mechanical properties, weight and cost are the basis criteria of this selection. The fiber volume fraction, fillers and type of fiber with three levels for each were considered to optimize the composite plate selection. Finite element method was used to investigate the stress distribution on the wing at cruise flight condition in addition to estimate the maximum stress. An experiments plan has been designed to get the data on the basis of Taguchi technique. The most effective parameters at the process to be find out by employing L9 (33) orthogonal array, signal to noise ratio (S/N), main effect and analysis of variance (ANOVA). The results show that, the experimental and the predicted results are very close. It was found that the type of fiber is the most effective parameter on the plate selection, followed by filler content and then the fiber volume fraction. The best parameters combinations are ((E-glass woven roving + unidirectional carbon) fiber, 7.5% graphite filler and 30% fiber volume fraction). This combination provides good mechanical properties, high safety factor, acceptable cost, and offers weight savings on average by 40% percent as compared to aluminum alloy.

Develop A new mathematical approach to predict the crack propagation rate in a thin plate subjected to in-plane biaxial loading

“…The total excess energy is: Physically, it has been scientifically proven in previous studies [11][12][13][14][15][16][17][18][19][20][21][22][23] that the deformation that appears at the crack edge, which forms the plastic area around and at the front of the crack, gives an enhancement to the resistance to the appearance of cracks. Therefore the necessary energy that the crack needs in order to start growing is higher in the crack at the middle because there are two tips of the crack in the center crack in the plate.…”

“…When the effective stress (𝛔eff) [23] for a combined mode that comes from tension load in the axis and cycling shear load in the elastic range in Pascal [21], as shown in Fig. 6, comes from the combination of tensile load and shear load cycling.…”