Ahmed S. Dalaq

Thermo-Electro-Mechanical Properties of Interpenetrating Phase Composites with Periodic Architectured Reinforcements

In this study, the multifunctional properties (thermal, electric, and mechanical properties) of a new type of three-dimensional (3D) periodic architectured interpenetrating phase composites (IPCs) are investigated computationally. These new IPCs are created using two interconnected, bicontinuous, and intertwined material phases. The inner reinforcing phase takes the shape of the 3D morphology (architecture) of the mathematically-known triply periodic minimal surfaces (TPMS). The TPMS reinforcements are 3D solid sheet networks with a certain volume fraction and architecture. The interconnectivity of the proposed TPMS-based IPCs provide a novel way of creating multifunctional composites with superior properties. In this study, the effect of six well-known TPMS architectures of various volume fractions on the thermal/electrical conductivity and Young’s modulus of the IPCs is investigated using the finite element analysis of a unit cell with periodic boundary conditions. The contrast effect (high and low) between the conductivities and Young’s modulus of the two phases is also investigated. The calculated effective properties are compared with some analytical bounds. The proposed TPMS-IPCs possess effective properties close to the upper Hashin-Shtrikman bounds. It is also shown that the effect of TPMS architecture decreases as the contrast decreases. Finally, the manufacturability of these new TPMS-IPCs is demonstrated through using 3D printing technology.

Invariants of mesoscale thermal conductivity and resistivity tensors in random checkerboards

Purpose – The purpose of this paper is to study the statistics of thermal conductivity and resistivity tensors in two-phase random checkerboard microstructures at finite mesoscales. Design/methodology/approach – Microstructures at finite scales are generated by randomly sampling an infinite checkerboard at 50 percent nominal fraction. Boundary conditions that stem from the Hill-Mandel homogenization condition are then applied as thermal loadings on these microstructures. Findings – It is observed that the thermal response of the sampled microstructures is in general anisotropic at finite mesoscales. Based on 1,728 boundary value problems, the statistics of the tensor invariants (trace and determinant) are obtained as a function of material contrast, mesoscale and applied boundary conditions. The histograms as well as the moments (mean, variance, skewness and kurtosis) of the invariants are computed and discussed. A simple analytical form for the variance of the trace of mesoscale conductivity tensor is pr...

An assessment of ocean wave, thermal and salinity energy potential in the junction of the Arabian Gulf and the Gulf of Oman

We present an overall assessment of the global picture of marine energy resources except tidal. Our focus is pointed to the Arabian Gulf and the straits of Hormuz. We make a mediocre estimate of deployment cost and impact for each of the related marine energies in the geographical areas in question and conclude that the region has renewable marine potential but is many magnitudes of scale away from the grand ocean potentials. In addition a multitude of factors, including political, industrial and those of infrastructure, contribute to the difficulty of the implementation of such projects in the region.