Ratnesh Raj

Bio: Ratnesh Raj is an academic researcher from VIT University. The author has contributed to research in topics: Materials science & Composite material. The author has an hindex of 2, co-authored 2 publications receiving 33 citations. Previous affiliations of Ratnesh Raj include University of Texas at Arlington.

Bird strike analysis of jet engine fan blade

Abstract: Bird strike, also known as avian ingestion, is the collision between a bird and an aircraft. Bird strikes have always been a cause of worry in the aeronautical industry: Aircraft both old and new have suffered from bird strikes. Jet engine ingestion occurs when the bird hits the jet engine of an aircraft and gets sucked in. Given that the fan blades rotate at a high rpm, bird strike on a fan blade causes its displacement into the adjacent blade. This leads to a cascading failure, wherein the entire system fails, thereby resulting in a lot of damage. In this article, we intend to investigate the construction of the fan blade and eventually strengthen its' resistance to bird strikes.

Print Parameter Optimization and Mechanical Deformation Analysis of Alumina-Nanoparticle Doped Photocurable Nanocomposites Fabricated Using Vat-Photopolymerization Based Additive Technology

Abstract: As the recent trend of fabricating high-strength polymer has been gaining more attention in the market, researchers are exploring the possibility of using a 3D printing technique for the same. Vat-photopolymerization additive technology has good process capability and produces high-quality photopolymer parts with greater geometrical complexity. This paper proposes the vat-photopolymerization process to fabricate high-strength acrylate-based photopolymer composite with improved mechanical strength. The composite structures contain 1.0, 2.0, and 3.0 wt percentages of 13 nm average-sized alumina (Al2O3) nanoparticle (NP) as the reinforcement and acrylate photopolymer as matrix material. The viscosities of all the prepared suspensions were measured to determine the printing properties of the prepared nanocomposites, and these values are within the feasible printing limit. Furthermore, the depth of cure and time of exposure to UV light were optimized to achieve the desired level of printing performance. The thermogravimetric analysis (TGA) of the alumina nanocomposites reveals that the addition of alumina NP has minimal influence on the thermal stability of the photopolymer matrix. To ascertain the mechanical strength of the 3D printed products, tensile tests are performed, and it was witnessed that 1.0% weight fraction of alumina-NP loaded specimen experienced the highest tensile strength amongst all the weight fractions of alumina-NP considered, and its value increased by ∼48% when compared against the pure acrylate polymer sample. The increase in strength values for the alumina-NP loaded specimen was explained using dynamic mechanical analysis and optical and scanning electron micrographs. A constitutive elastic-viscoplastic isothermal non-linear time-dependent material model is also developed to predict the post-yield strain-softening behavior of these nanocomposites. The weight fraction and optimal weight fraction of alumina nanoparticles are correlated using semi-empirical equations of various model parameters.

Print fidelity evaluation of PVA hydrogel using computational fluid dynamics for extrusion dependent 3D printing

Abstract: This study presents a practical method of print fidelity evaluation for an extrusion-dependent technique of 3D printing. Simulation through computational fluid dynamics (CFD) tool has been used for evaluating the fidelity of printing. The polyvinyl alcohol (PVA) based hydrogel was prepared with deionized (DI) water and PVA powder using a magnetic stirrer at 90 °C for 3D printing. Rheological tests were carried out for checking the viscosity at various shear rates. CFD simulation was done by employing the Bird-Carreau modelusing rheological values. Velocity, pressure, shearing rate, and viscosity distributions through nozzle were obtained. From the shear rate and viscosity results, the increase in shear rate and decrease in gel’s viscosity for both the nozzles prove that the material can be extruded. It was seen that the nozzle with a diameter of 0.51mm shows better results than the 0.41mm diameter, which was concluded from the values of maximum shear rate at the edges of the nozzles. The maximum shear rate value has reached a maximum of up to 326.5102s –1 whereas for a 0.41 mm diameter nozzle, it is 623.8037s –1 increasing the chances of developing wavy edges in a 0.41mm diameter nozzle than a 0.51mm diameter nozzle concluding that the nozzle with 0.51mm diameter gives far better results than the 0.41mm diameter nozzle.