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We investigated the effect of Halloysite nanotube (HNT) addition on the interfacial and bending properties of hybrid composites. Test specimens were prepared using a vacuum bag method, which is manufactured by using an autoclave device. Ultrasound device was used to uniformly disperse HNT nanoparticles into the epoxy. Amount of the nanoparticles was determined by the weight of the epoxy resin. The Fracture toughness, ILSS and bending strength of Aramid/Basalt fiber hybrid composite specimens were decreased by more than certain amount of HNT. This phenomenon is presumably due to aggregation of HNT.

This study deals with the investigation on the effect of Electrical Discharge Machining (EDM) parameters during machining of hybrid composite (Al 7075/TiC/B₄C). The optimum process parameters of die sinking EDM like pulse current, pulse duration and gap voltage on metal removal rate, tool wear rate and surface finish were investigated. Full factorial experimental design was selected for experiments. Analysis of variance was employed to study the influence of process parameters and their interactions on response variables. Among the process parameters considered, it was observed that the pulse current was found to be more influential in affecting MRR, TWR and SR. The other parameters have little effect on the response variable. Multi-objective optimization study was also performed using genetic algorithm to find the optimum parameter setting for controversial objective function combination such as high MRR and low SR and High MRR and low TWR. Scanning electron microscope study was performed to study the surface characteristics.

Machining of accurate geometrical profiles like triangles, squares or circles with good surface finish and high productivity in metal matrix composites is required for various industrial applications. Thermoelectic principle-based wire electric discharge machine (WEDM) can be conventionally used to overcome the difficulty which occurs during the machining of composites due to the presence of hard abrasive particles. Therefore, in this investigation, three geometrical profiles possessing equal perimeters were produced in 5 mm thick aluminum metal matrix composites (AMMCs) by WEDM. In order to analyze the effect of reinforcements three different AMMCs containing Al6061 as a matrix were produced by stir casting method. The fabricated composites, respectively, contain 10% alumina (${\mathrm{\text{Al}}}_2{\mathrm{\text{O}}}_3$), 10% silicon carbide (SiC) and a mixture of 5% ${\mathrm{\text{Al}}}_2{\mathrm{\text{O}}}_3$ with 5% SiC. The individual effect of various input parameters like pulse-on time ($T_{\text{on}}$ = 30-50 $\mu$s), pulse-off time ($T_{\text{off}}$ = 6–12 $\mu$s), current ($I$ = 1–5 A) and geometrical shapes (circle, triangle, and square) on cutting velocity (CV) and surface roughness (SR) were investigated. Furthermore, parametric analysis using regression models was also performed to evaluate the simultaneous effect of two interacting parameters on CV and SR. The study reveals that in the case of hybrid composite, CV decreases with $T_{\text{on}}$ and SR is always higher for triangular profiles when $T_{\text{on}}$ and $I$ change. The regression plots indicate that the interaction effect of $T_{\text{off}}$ × $I$ plays a major role in CV for all three composites. Multiobjective optimization using a composite desirability approach reveals a marginal increase in CV (8.58%) and a significant reduction (57.72%) in SR at optimal input parameters for Al6061–10% SiC. The morphological analysis at optimal input parameters indicates a significant reduction in resolidified metal drops and microcraters.

The vibrational behavior of polymer matrix nanocomposite plates reinforced with carbon fibers (CFs) and carbon nanotubes (CNTs) is studied using the finite element method based on a multi-scale modeling approach. The influences of nano- and micro-scale are coupled through a two-step procedure. First, CNTs are dispersed into the polymer matrix. In the selected representative volume element (RVE), interphase due to chemical interaction between CNT and polymer matrix is considered. Also, the state of dispersion of CNTs into the matrix is assumed to be random. In the second step, CFs are randomly distributed in the reinforced polymer with CNTs. The reinforcement is carried out for various volume fractions of CFs and CNTs. Two three-dimensional models including the brick and shell ones are used to generate the results. Moreover, the analysis is presented for square plates under different types of boundary conditions. The effect of nanocomposite thickness on its vibrational response is also investigated.

The time-dependent deflection values of the flat/curved hybrid fibre (Glass–Carbon–Kevlar)-reinforced composite panels under the influence of the mechanical loading (UDL and SDL) and the elevated thermal environment are analyzed in this research. To compute the numerical responses, a higher-order kinematic model is prepared considering the effect of single/double curvature of the shell panel. The weak form of the governing equation is established through the variational technique. The steady-state deflections are obtained by solving the discrete form of governing equation of transient vibrations using finite element method (FEM) by employing Newmark’s time integration method in MATLAB environment. The isoparametric Lagrangian element (nine-noded) is adopted to discretize the system equation of the hybrid panels. The validity of the numerical solutions, computed using the experimental hybrid composite properties, is verified with the experimental (in-house) results as well as with the benchmark results available in the published literature. Finally, the parametric study of dynamic deflection characteristics of hybrid composite shallow shell panels is carried out by varying the parameters such as curvature ratio, support conditions, hybrid schemes and type of loading in the elevated thermal environment and the results are discussed in detail.

In this work, reduced graphene oxide (RGO)/ferroferric oxide (RGO/Fe₃O₄) hybrid composite was successfully fabricated by a facile one-step solvothermal method. The structure, chemical composition, morphology and magnetic properties of the samples were investigated in detail. Fe₃O₄ microspheres with an average diameter of 250nm were uniformly anchored on the surface of the RGO sheets without large aggregation. Moreover, the results demonstrated that the hybrid composite exhibited obviously enhanced microwave absorption properties compared with the pure Fe₃O₄ microspheres. The minimum reflection loss (RL) of the hybrid composite reached $-$36.8dB at 17.2GHz with a thickness of 5.0mm and its effective absorption bandwidth (lower than $-$10dB) was 3.9GHz with a thickness of 2.5mm. Significantly, the hybrid composite exhibited a dual-waveband absorption characteristic covering the C and Ku bands. Besides, the relationship between the matching thickness and peak frequency was reasonably explained according to the quarter-wavelength matching theory. Therefore, the obtained composite was a promising candidate for application in microwave absorption.