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Effect of geometrical parameters including core separation between two fused fibers and coupling length on output characteristics of 2×2 single mode fiber (SMF) coupler at 1550nm band is studied. Simulations are carried out by using BPM CAD software. The simulation data is then used to manufacture 2×2 SMF coupler. Parameters are optimized to achieve 50∶50 coupling ratio. The error in measured results...
Plasma spray physical vapor deposition (PS-PVD) is a promising technique used to manufacture strain tolerant and non-line-of-sight thermal barrier coatings (TBC). It bridges the gap between conventional plasma spraying and electron beam physical vapor deposition (EB-PVD). In this study, the effect of different compositions of Ar/He plasma on particle characteristics and coating morphologies of 7∼8...
A high density reactive structural material can potentially replace steel for its use as a casing structural material in ammunitions. Reactive casing can increase lethality because reactive fragments will impart kinetic and chemical energies. Tungsten was added in four different energetic compositions which included Al-PTFE-viton, Al-Ni and two hybrids Al-PTFE-Ni & Al-PTFE-viton-Ni. Al-PTFE-Viton-W...
Research on micro and nano-dielectrics has shown that amalgamation of micro/nano particles into polymer usually enhances its mechanical, thermal and erosion/tracking characteristics. Due to organic-nature, silicone rubber (SiR) insulator outer sheath and weather-sheds are susceptible to environmental and electrical stresses, which lead tracking/erosion of outer surface. In this paper, we have investigated...
Polymer matrix reinforced composites (PMCs) are being widely used in different applications, due to their variety of properties. PMCs have a drawback of flammability. Flame retardants are being incorporated in two ways, either as an additive or reactive material. Cartek 1709 (Ck) is a recognized flame retardant coating system, however, their flame retardant performance has not been established yet,...
Liquid phase exfoliation method is used to achieve three different sized (L≈0.4, 1, 1.9 µm) hexagonal Boron Nitride (hBN) nanosheets by changing the centrifugation rate. Mechanical properties of polymer composites are evaluated with hBN nanosheets utilized as reinforcement filler in polyvinylchloride (PVC) matrices. In an earlier work, uniaxial drawing (300%) was successfully employed to enhance the...
This study was carried out to assess the effects of cold deformation on the dimensional stability and yield to tensile ratio in AA6061-T6X aluminium alloy. Dimensional changes observed after the machining are mostly related to metal forming operations such as extrusion or forging and solution heat treatment processes. These processes generate severe stresses inside the material which causes machining...
High volume fraction silicon carbide-reinforced aluminum matrix composites (SiCp/Al) have many excellent properties while they are one of typical hard-to-machine materials. Due to the existence of hard SiC reinforcements, it is very difficult to machine holes of this material, especially small-diameter holes. Rotary ultrasonic drilling (RUD) is a suitable machining method to process hard brittle materials...
In this study, Zinc oxide nanorods has been inspected under wide range of rapid thermal annealing temperatures to explore the optimum post growth annealing temperature, required for particular applications, under structural, electrical and optical properties. Vertical ZnO Nanorods has been grown via low temperature hydrothermal route on Silicon substrate, then the as-grown NRs were undergone through...
High temperature resistance improvement (500 °C) and corrosion resistance in salt spray test (47 °C) at different time intervals with and without surface modified with Ni coating of SmCo alloy was carried out. The results showed that mass gain of Ni coated sample is far less then uncoated sample when oxidized at 500 °C for 300h and the loss of magnetic properties for coated magnets were also almost...
Solar Array Drive Assembly (SADA) can dramatically restrict scientific space missions as it generates micro-vibrations that can significantly alter position precision and reduce pointing accuracy of satellite. The main disturbance causing factors are structural and electromagnetic coupling between Solar Array Drive Assembly and its operated load. The present study analyses these disturbances when...
Due to the high stiffness-to-weight and strength-to-weight ratios, Carbon Fiber Reinforced Polymer (CFRP) based composite materials are gaining increasing attention and growingly applied in modern aircraft structures. As one of the load-carrying members, the stiffened panels are widely used in the aircraft structures, such as: fuselage, wing and tail. These thin walled panels will buckle under the...
Experimental investigation was carried out to compare mechanical properties of composite laminates made from multidirectional plies and those of Chopped Strand Mat (CSM). All the samples were fabricated according to available ASTM standards. Laminates with six different configurations were made using fiber glass roving and two types of matrix materials which were polyester and epoxy resins. The fabrication...
Non Destructive Testing (NDT) has been used in aviation industry to predict remaining useful life (RUL) of aerospace structures. RUL knowledge enables aircraft maintenance managers to plan repair/replacement actions well in time thereby making flight operation safe with reduced downtimes. Different Model-based, Stochastic-based and Data-based models are used for prognostics and remaining useful life...
Wing weight estimation is one of the most important functions of the aircraft design process. For optimization process, the weight of the wing may have to be calculated thousands of time specially if it is a part of multidisciplinary optimization. For light weight UAV, four different models are used to calculate the weight of ribs, skin, spar and carry through structure respectively. Ingenuity is...
Carbon fiber reinforced polymers (CFRP), have got rapidly enhanced applications in aerospace and other fields due to their attractive properties of high specific strength, high specific stiffness, and low thermal expansion. However, their properties like inhomogeneous, anisotropy and low heat dissipation are the main hindrance for machining of such materials with desired quality. In this research,...
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