Aerospace Engineering

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be...

This project is modeled around reducing the overall drag and lift coefficient by modifying the geometry and comprehending the underlying rootphenomenon for the variation in these drag values. The designing of models used in this project is done through SOLIDWORKS, and CFD simulation in FLUENT (ANSYS) respectively. The purpose of this project is to reduce the inefficiency caused due to aerodynamic factors of drag, lift by presenting development, design and optimization of the geometry modifications of the base model. The improvement of aerodynamic behaviour around the periphery of the model is investigated through numerical simulation. The Ahmed Reference Body having 10 degree rear slant angle has been taken as benchmark model in this paper. Simulation of variants of multifarious modifications and examination of their results is performed to find the best suited variant form (dimension) to boost the aerodynamic efficiency of the model. CFD simulations on Ahmed Body were carried out in order to serve as a benchmark for validating all the simulation results. The steady-state simulations are based on the Reynolds averaged Navier-Stokes equations, with turbulence closure provided through two-equation k-epsilon realizable models.

Sometime in the 1950s while experimenting with tip-mounted ramjet engines, Eugene M. Gluhareff built the first working pressure jet engine, a variation on the classical ramjet engine that uses an acoustically-pressurized inlet system to boost the chamber pressure at static
conditions to produce efficient thrust. Despite successful development and varied applications, Gluhareff himself never published his design methods nor any extensive information on the engines except what was necessary to sell his design. This study has compiled much of the
limited data available on Gluhareff’s engines and attempted to reverse engineer as many of its design principles as possible. It details what is known about the engine’s design and operation and works to match scaling trends with injector sizing. All sizing trends with the exception of thrust force were found to have reasonably good linear trends as represented by R-squared values. This study concludes with a discussion of past applications of the engine and the potential for future study of the pressure jet and its design principles.

Efforts are being taken to make space missions more affordable. Reusable Launch Vehicle (RLV) is one such innovation aimed to reduce the manufacturing costs drastically. Developments are being made to make improvements on the already existing landers and also to make the full rocket reusable. This article examines the present state of the technology for reusable launch vehicles. and also aims to provide an enhancement to the already existing landing legs used on reusable launch vehicles (RLV) which can help the rocket land on uneven surfaces. This landing mechanism employs honeycomb shock absorber to absorb the energy during landing. The main purposefulness of this idea is to avoid the moment which topples the rocket during landing on uneven terrain. The paper also provides results from various analyses conducted to support the proposed idea.

It is a precious knowledge of ancient india. this script was originally composed by mahrshi BHARADWAJA, the great indian sage around 5000 BC  ,it content english transtation of some of its sanskrit stotras and shlokas.before wright brothers first aircraft was made by dr Talpade was an Indian scholar who is said to have constructed and flown an unmanned airplane in 1895 with reference of this ancient hindu sanskrit manuscript .

Aircraft is a brilliant man-made structure which helps us to fly over the world. At the same time, aircraft is a complex structure to be checked and maintained for the aero elasticity due to aerodynamic properties. In this paper, the fluid-structure interaction problem in super critical NASA SC(2)-0412 airfoil is discussed. The main aim of this project is to find the best performance and deformation limit of the wing on different Mach numbers. This project is completely done by numerical methods of designing the wing using CATIA and flow properties in Computational Fluid Dynamics (CFD) method. Finally, the structural analysis for deformation is analysed in ANSYS. The analytical approach of fluid-structure interaction over an Aircraft wing is complex.

The paper is about preliminary sizing and analysis of a trainer aircraft wing. The main objective is to fix an appropriate
structure within the given envelope and to estimate the Gross take-off weight, wing loading, Stress distribution, low
frequency vibrational modes, take-off distance and stall velocity. Sizing is done by using classical engineering theories and
FEA packages. Skin and web are considered as shell elements. Flange, spar and stringer are considered as beam elements.
From the analysis structure has been optimally designed which satisfies the strength and stability criteria. The detailed
design of trainer aircraft wing structure is modelled using CATIA V5 R20. Then stress analysis of the wing structure is
carried out by using the finite element approach with the help of MSC NASTRAN/PATRAN to find out the safety factor of
the structure.

Vent holes can be used to reduce the aerodynamic pressure loads on nonstructural elements of buildings. The analysis of these loads applied on nonstructural elements of buildings (window panes, closure panels, etc.) with vent holes, under gusty wind conditions, have been studied both experimentally and employing a theoretical model. An experimental setup based on an open circuit, closed test section, and low speed wind tunnel, designed and built at the Instituto de Microgravedad “Ignacio Da Riva” of the Universidad Politécnica de Madrid (IDR/UPM) has been used. A mechanism in the wind tunnel generates sinusoidal gusty winds inside the test section. Theoretical predictions of the pressure loads have been obtained using a mathematical model based on the mass conservation equation and polytropic law gas evolution. In the experimental setup, an air reservoir with a vent hole has been selected as a model to simulate the internal pressure loads acting on the walls of a building under a ta...

This paper describes the summary of a three-year development program for the first-stage stationary vane and rotating blade for the next generation, 1500°C class, high-efficiency gas turbine. In such a high-temperature gas turbine, the first turbine vane and blade are the most important hot parts. Full-coverage film cooling (FCFC) is adopted for the cooling scheme, and directionally solidified (DS) nickel base superalloy and thermal barrier coating (TBC) will be used to prolong the creep and thermal fatigue life. The concept of the cooling configuration, fundamental cascade test results, and material test results will be presented.

A radio heliograph operating in the frequency range of 1200–1700 MHz is planned by INPE, Brazil, for investigations of time evolution of active regions, which will lead to better understanding of the physics of the flares energy release and particle acceleration, in order to suggest better criteria for the prediction of solar flares, Coronal Mass Ejections (CME), and solar terrestrial relations, such as geomagnetic storms and radio blackouts. In the first phase, the Brazilian Decimetric Array (BDA) will be a T shaped array 256 m by 144 m, consisting of 26 parabolic dish antennas of 4 m diameter. This array will produce full disk images of the sun with a spatial resolution of 3 by 5 arc minutes at 1420 MHz with a time resolution of 100 ms and sensitivity of ∼ 10 Jy. In the second phase, in addition to the compact T array there will be 6 more 7 m diameter antennas on an East-West baseline of 2560 m to obtain higher spatial resolution and better sensitivity. Thus, finally this radioheliograph will have wide field of view and couple of arcsec spatial resolution and high time resolution (100 ms).

Measurements of the velocity and concentration in axisymmetric, turbulent, isothermal and buoyant jets have been performed with laser-Doppler velocimetry and planar and point laser-induced fluorescence to quantify the mixing enhancement achieved by periodic forcing when the jet exit has a fully-developed turbulent pipe flow, a situation less well-studied than the case of laminar initial conditions. It was found that forcing at Strouhal numbers around 0.6 enhances mixing in the developing region of the jet and this enhancement increased with increasing amplitude of excitation, consistent with results of initially-laminar jets. The initial turbulence intensity did not have any effect, but an increase in the initial lengthscale of the turbulence, controlled by a perforated plate inside the nozzle, caused faster mixing. In agreement with previous experiments, the initial conditions of the jet did not affect the far-field rate of decay, but the jet-fluid concentration there was significantly reduced by forcing due to the increased mixing during the early stages of development, an effect that can be described by a smaller virtual origin in decay laws of jet decay. These results are independent of the Froude number because the initial conditions have an influence only in the early stages where the flow is still momentum dominated.

The complexity of the conceptual design of tailless aircraft can appear daunting to many. The multiple design aspects that are able to be broken out into individual problems on conventional designs, are all interrelated on the tailless aircraft configuration. This paper documents additional methods for tailless aircraft design for aspect ratios ≤ 10, and sweep angles ≤ 45°. These methods are based upon well known references that should be readily available to any designer during the conceptual design phase. Since better tools exist in the major design houses, it's assumed that a majority of conceptual designers using these methods would be homebuilt aircraft enthusiasts or modellers. Nomenclature A = wing aspect ratio c' = wing mean aerodynamic chord í µí° ¶ í µí°· í µí°¿ = wing drag coefficient due to lift í µí° ¶ í µí°¿ = wing lift coefficient í µí± ℓ í µí»¼ = airfoil section lift curve slope í µí° ¶ í µí±š = wing pitching moment coefficient í µí° ¶ í µí±š 0 = wing zero-lift pitching moment coefficient (í µí° ¶ í µí±š 0) í µí¼ƒ=0 = wing zero-lift pitching moment coefficient with zero twist ∆í µí° ¶ í µí±š 0 í µí¼ƒ = change in wing zero-lift pitching-moment coefficient due to a unit change in linear wing twist í µí± í µí±š 0 = airfoil zero-lift pitching moment coefficient í µí±‘í µí° ¶ í µí±š í µí±‘í µí° ¶ í µí°¿ = static margin (-x/c') e = Oswald span efficiency M = Mach number í µí±£ = induced-drag factor due to linear twist í µí±¤ = zero-lift drag factor due to linear twist x = distance from the center of gravity to the aerodynamic center  = compressibility factor (√1 − í µí±€ 2 í µí±“í µí±œí µí±Ÿ í µí± í µí±¢í µí±í µí± í µí±œí µí±›í µí±–í µí±) í µí¼ƒ = wing twist (positive for washin, negative for washout)  c 4 ⁄ = wing sweep measured at the ¼ chord point  = wing taper ratio í µí»¾ = compressibility correction factor to the wing zero-lift pitching moment coefficient ((í µí° ¶ í µí±š 0) í µí±€ (í µí° ¶ í µí±š 0) í µí±€=0 ⁄)

The role of transverse shear is crucial in modeling ultrasonic wave propagation in composites. The approximate plate theories have been extremely useful in providing solutions to problems involving static and dynamic loadings of uniform or laminated plates of finite dimensions. Moreover, since their simple formulations, they can also be useful for solving wave propagation problems in laminates of finite thickness and large lateral dimensions. A four-node plate bending element based on first order shear deformation theory is used in this work to predict the propagation velocity of first antisymmetric Lamb wave mode in graphite/epoxy composite plates by numerical simulation. Calculations are made using material properties obtained from a unidirectional panel via mechanical tests. For investigation, propagation along multiple directions is evaluated. Experimental and numerical results are compared at different angles of propagation and agreement between experimental and numerical approaches is found. © 2014 Elsevier Ltd.

Abstract This paper proposes an MPC based compound flight control technique for trajectory tracking and attitude control for a ducted fan aircraft subject to different uncertainties and external disturbances. This approach aims to ensure flight robustness and achieves adequate tracking without sacrificing nominal performance while satisfying constraints under external disturbances and various uncertainties. A nonlinear ducted fan aircraft with non-minimum phase behavior is considered. By unifying a nonlinear disturbance observer with MPC, a compound flight controller is constructed. The recursive feasibility of the optimization problem for the compound controller is guaranteed, and the closed-loop stability is ensured. To demonstrate the effectiveness of the developed scheme, a robust MPC framework is employed for comparative analysis. Finally, numerical simulations and discussions are provided to corroborate the performance of both compound strategies.