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The mechanical properties and microstructure of heat treated 6082 wrought aluminum alloy was studied. The aim of this work was to study the merits and demerits of natural aging and artificial aging on material properties. The precipitation hardening of aluminum alloy usually undergoes a thermal treatment consisting of heat treatment, quenching and aging. Experiments were carried out for different...
In the paper, on the basis of the solution of the biharmonic problem for a smooth semi-strip, is first constructed the exact solution of a boundary value problem for a semi-strip whose longitudinal sides are supported by stiffeners. The solution is given in the form of explicit expansions in Papkovich-Fadle eigenfunctions. The coefficients of the expansions are determined by simple formulae as the...
For the numerical simulation of the hypersonic vehicle aerothermal heating, the grid-dependency of the aerothermal computation under the hypersonic flow was studied by the means of computational fluid dynamic. By employed two-dimensional cylinder model, researched the influence of the grid-reynolds number Recell to heat transfer simulation, and established the connection between grid refinement in...
Numerical analysis of convective heat transfer process was conducted to accurately describe the energy balance of the airfoil ice protection area. The convective heat transfer coefficient around the leading edge was calculated using four different turbulent models, including the Spalart-Allmaras model, the k-ε model, the k-ω model, and the transition SST model. Results were compared with icing tunnel...
Aluminum metal matrix composites (AMMCs) reinforced with ceramic particles have different and many uses in multi industrial applications due to their excellent characteristics. The present work is aimed at studying the preparation of AMMC reinforced with particles of cement kiln dust (CKD). A base alloy of (Al+2%Mg) had been prepared by using powder metallurgy technique with a determined suitable...
The influence of void distribution on the transverse mechanical properties of unidirectional composites is studied. Firstly, using Matlab to obtain composites microscopic voids radius distribution. Secondly, based on void radius distribution, the representative volume element (RVE) of composites microstructure with random fiber, matrix, and random voids are generated by random algorithm. Finally,...
Cat free fall righting maneuverer has inspired many aerial, space and legged robotic research. Conservation of angular momentum principle is used to derive the inverse differential kinematic and TMT vector form dynamics of the motion for three robotic models: a two-link model, a three-link model with tail, and a comprehensive eight-link model with the addition of legs. The path planning problem in...
The effects of configuration and fiber orientation on the performance of fiber metal laminates (FMLs) subjected to low velocity impact has been investigated. A finite element model has been firstly validated credible, and then it was adopted to simulate the impact response of other four types of FMLs with some differences in configuration or fiber layup orientation to compare with the experimental...
This article aims to seek approaches to modeling and controlling the motion of mass-flexible structure systems composed of two lumped masses connected by two flexible structures modeled as distributed masses. The system model is first developed, and the system transfer function is then determined. With the system model, there are two control schemes (feedback control and feedforward control) proposed...
Turbulence and shock waves interactions occur in a wide range of applications, such as mixing, flow separation and combustion. However, it is still a challenge to accurately simulate these problems. The two demands seem contradictory: the simulation of small turbulence scales requires non-dissipative scheme while the capture of shock requires dissipative scheme. We evaluate the performance of several...
The study of high accuracy numerical schemes is a hot topic for decades in the field of compressible turbulence simulations. Linear compact schemes, high-order shock-capturing schemes and the hybrid schemes are three types of schemes used in today's turbulent flow simulations. The fifth-order compact scheme, WENO scheme and hybrid compact-WENO scheme are introduced as the representatives of these...
This paper proposes a method to make supersonic axisymmetric mixed-compression multi-inlets get into the single subcritical condition by numerical simulation. The flow mechanism in the inlets and the changing rule of the aerodynamic performance of the missile under this condition have been studied. The results when supersonic inlets get into single subcritical condition are concluded as follows: (1)...
The common challenge of all aerospace advancements is greening the air transport. This led the recent research programs towards the study of “metamorphic” wing structures, capable of adapting their geometry to the different conditions of flight. The development of morphing structures allows the reduction of drag and the increase of range, together with the growth of load control effectiveness. In...
In the present work a study of the burning velocity of hydrogen and mixtures of methane and hydrogen in different proportions obtained in a constant volume combustion bomb is presented. Hydrogen is an important energy carrier that contributes to the energy diversification and can be produced from different fossil and renewable energy sources. This work describes a method to determine laminar burning...
Gears are used in different industries from machine and equipments manufacturing to automotive industry, from energy industry such as steam and hydraulic turbines, wind turbines to aeronautics such as helicopter and aero plane industries. There is an increasing demand for gears which work at high speeds and carry high loads, so there is more need for gear research and development activities on gear...
According to the structure of the newly high precision F2C-T pin-cycloid transmission, influence factors on the transmission error were analyzed, and the error synthesis model of the various driving factors and parts were established. Taking the F2C-T455 model as an example, the theory of transmission error were analyzed, comparing contribution rate by driving factors of each part, the main influence...
The aim of this work is to provide a promising way to accelerate the structure design procedure and overcome heavy burden from meshing. The Isogeometric Analysis (IGA) appears in recent years and soon grows up as a powerful means to eliminate gaps between Computer Aided Design (CAD) and Computer Aided Engineering (CAE), due to the abilities of both complicated geometry description in CAD software...
Numerical simulation have been undertaken to investigate the forced convention heat transfer of carbon dioxide flow over the Mars rover under the Martian conditions. The study is carried out based on a simplified Mars rover model which is a cuboid with longer and wider top surface and it is performed under the conditions of temperature 160 K and 290 K, Reynolds numbers of 6.64×103 to 7.01×104 and...
Deployable radiator is a radiation cooling device which is folded next to side wall of spacecraft while launching, and can expand itself after the spacecraft is on track. It can effectively improve the cooling capacity of the spacecraft. In this paper, the current research and development situations of the deployable radiator were studied and analyzed. Depending on this, design and simulation of the...
skCUBE is 1U cubesat designed and developed in Slovakia over a period of years from 2012–2015 with expected launch in to the low-Earth orbit in 2017. It carries an experimental very-low-frequency (VLF) radio waves detector, which will attempt to record whistlers — radio signals from dispersed radio frequency components of lightning's. A lot has been found about these radio waves caused by classical...
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