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The response of aluminium plates (6061-T6) under low velocity impact is investigated numerically using ABAQUS software package. Firstly, the effect of the sample thickness on the perforation resistance of the aluminium plates is undertaken. It was shown that the perforation behaviour of the plates investigated increases with the target thickness and the maximum resistance to perforation, for the range of thicknesses investigated, was achieved using 4 mm thick panels. In order to capture the influence of the projectile shapes on the perforation behaviour, the aluminium plates were impacted with different head shapes impactors. The results showed that plates impacted with a flatted impactor offer the highest perforation resistance. Moreover, the results showed that changing the size of the targets has no significant change on the dynamic behaviour of the plates investigated in this study. Finally, it is suggested that the finite element models developed in this study can be used to capture the effect of the geometric and loading conditions of aluminium plates under perforation by low velocity impact.

The contact angle is very important parameter in improving the self-cleaning property as well as in increasing the wear resistance of engineering surfaces in addition to improving the thermal transfer properties of materials in general. In this study, titanium dioxide nanoparticles were added to the epoxy resin and sprayed on a substrate of the brass tube used in heat exchangers for the purpose of studying its effect on the angle of contact of the substrate where different proportions of the nanomaterial were added to the epoxy resin in (1%, 3%, 5%, and 7%)wt. The results showed that the contact angle increased with increasing the rate of titanium dioxide nanoparticles.

Numerical method is used to solve the two-dimensional transient natural convection heat transfer problem in an inclined shallow porous cavity. A constant heat flux is applied for heating and cooling all opposing walls. Solutions for laminar case are obtained within Rayleigh number varied from 20 to 500 and aspect ratio for porous cavity varied from 2 to 4. A finite difference method is used to obtain numerical solutions of full governing equations. Energy equation is solved using alternating direct implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. The results are presented for the flow filed, temperature distributions, and average Nusselt number in terms of the Rayleigh number, aspect ratio, and the inclination angle of cavity. the convection becomes more and more vigorous as the orientation angle of the cavity is increased and for high Rayligh number no steady unicellular flow could be maintained inside the cavity. The effect of inclination angle on Nasselt number is more pronounced as the Rayleigh number is increased. When the inclination angle increased the Nusselt number increased and sudden transition appears and flow becomes unicellular and Nusselt number increased clearly. The value of mean Nusselt number strong function with the value of Rayleigh number, aspect ratio and the orientation of porous cavity.