scholarly journals Study on the Damage Mechanism of TiN/Ti Coatings Based on Multi-Directional Impact

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 765 ◽  
Author(s):  
Zhihao Fang ◽  
Jiao Chen ◽  
Weifeng He ◽  
Zhufang Yang ◽  
Zhanwei Yuan ◽  
...  
Keyword(s):  
High Speed ◽  
Damage Mechanism ◽  
High Impact ◽  
Vacuum Arc ◽  
Magnetic Filter ◽  
Gas Gun ◽  
Aero Engine ◽  
Application Potential ◽  
Cracks Propagation ◽  
Peeling Off

TiN/Ti coatings have great application potential in improving aero-engine server lives in a dusty environment. However, the damage behavior and mechanism of the coating and substrate under high impact speed and multi-direction loading conditions has scarcely been investigated. In this paper, TiN/Ti coatings were deposited on Ti6Al4V alloys by a magnetic filter cathode vacuum arc. Multi-directional impact tests were carried out by a gas gun system at, 45°, 60°, and 90° with a velocity of 330 m/s. The damage behaviors and mechanisms of the TiN/Ti coatings were investigated and revealed by researching the damage morphology, crack propagation, and stress distribution. The results show that plastic deformation occurs both in the coatings and the substrates under high speed impacting. Cracks extend vertically downward in the TiN layer first and are deflected at the Ti layer when the driving force is not enough. Circular cracks and radical cracks are found to form network cracks on the surface of the coating and the shear stress loaded by the particles, which drives cracks’ propagation is the main reason for the peeling off on the coatings.

scholarly journals The Influence of the Axial Rub Added in the Radial Rub on the Wear of the Seal Fins during the High Speed Rub of Labyrinth-Honeycomb Seal

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1997
Author(s):  
Bin Lu ◽  
Haijun Xuan ◽  
Xiaojian Ma ◽  
Fangjun Han ◽  
Weirong Hong ◽  
...  
Keyword(s):  
Wear Rate ◽  
High Speed ◽  
State Of The Art ◽  
Negative Influence ◽  
Axial Thrust ◽  
Cross Sectional ◽  
Honeycomb Seal ◽  
Aero Engine ◽  
Honeycomb Seals ◽  
Clearance Change

Labyrinth-honeycomb seals are a state-of-the-art sealing technology commonly used in aero-engine interstage seal. The undesirable severe rub between the seal fins and the honeycomb due to the clearance change may induce the cracking of the seal fins. A pervious study investigated the wear of the seal fins at different radial incursion rates. However, due to the axial thrust and mounting clearance, the axial rub between the seal fins and the honeycomb may occur. Hence, this paper focuses on the influence of the axial rub added in the radial rub on the wear of the seal fins. The rub tests results, including rubbing forces and temperature, wear rate, worn morphology, cross-sectional morphology and energy dispersive spectroscopy results, are presented and discussed. Overall, the participation of the axial rub leads to higher rubbing forces, temperature, and wear rate. The tribo-layer on the seal fin is thicker and the cracks are more obvious at high axial incursion rate. These phenomena indicate the axial rub has a negative influence on the wear of the seal fins and should be avoided.

scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

scholarly journals MEASURING DISPLACEMENT AND VELOCITY OF A STRIKER USING A RADIO-INTERFEROMETER

2019 ◽  
Vol 81 (1) ◽  
pp. 118-128
Author(s):  
V. V. Balandin ◽  
V. V. Balandin ◽  
V. V. Parkhachev
Keyword(s):  
High Speed ◽  
Radio Interferometer ◽  
Experimental Investigations ◽  
X Ray ◽  
Gas Gun ◽  
Impact Interaction ◽  
Ballistic Experiment ◽  
Wide Range ◽  
Series Of Experiments ◽  
Error Of Measurement

Investigating impact interaction of solid and deformed bodies with obstacles of various physical natures requires developing experimental methodologies of registering the parameters of the interaction process. In experimental investigations of impact interaction of solids, it is common practice to measure displacement of strikers as a function of time, as well as their velocity and deceleration. To determine the displacement and velocity of a striker, a radio-interferometric methodology of registering the displacement of its rear end is proposed. In contrast with the registration methods based on high-speed filming and pulsed X-ray photography, the method using a millimeter-range radio-interferometer provides continuous high-accuracy registering of the displacement of the rear end of a striker in a wide range of displacement values. To test the effectiveness of the methodology, a series of experiments have been conducted on registering the motion of a cylindrical striker of an aluminum alloy, fired from a 20mm-dia gas gun. The displacement of the striker was also monitored using high-speed filming. The results of measuring using the two methodologies differ within the limits of the error of measurement. Based on the results of the above experiments, it has been concluded that the methodology of determining the displacement and velocity of strikers in a ballistic experiment using a mm-range radio-interferometer makes it possible to measure practically continuously large displacements (100 mm and larger) to a safe accuracy. The present methodology can be used for measuring the displacement and velocity of the rear end of a striker interacting with obstacles of various physical natures (metals, ceramics, soils, concretes, etc.).

scholarly journals Dynamic properties of stainless steel under direct tension loading using a simple gas gun

2018 ◽  
Vol 183 ◽  
pp. 02035 ◽  
Author(s):  
Anatoly Bragov ◽  
Alexander Konstantinov ◽  
Leopold Kruszka ◽  
Andrey Lomunov ◽  
Andrey Filippov
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Tensile Load ◽  
Hopkinson Pressure Bar ◽  
Direct Tension ◽  
Stress Strain ◽  
Gas Gun

The combined experimental and theoretical approach was applied to the study of high-speed deformation and fracture of the 1810 stainless steel. The material tests were performed using a split Hopkinson pressure bar to determine dynamic stress-strain curves, strain rate histories, plastic properties and fracture in the strain rate range of 102 ÷ 104 s-1. A scheme has been realized for obtaining a direct tensile load in the SHPB, using a tubular striker and a gas gun of a simple design. The parameters of the Johnson-Cook material model were identified using the experimental results obtained. Using a series of verification experiments under various types of stress-strain state, the degree of reliability of the identified mathematical model of the behavior of the material studied was determined.

Spatio-Temporal Development of Supercavitation Over an Impulsively Launched Projectile

2006 ◽  
Author(s):  
C. J. Weiland ◽  
P. P. Vlachos
Keyword(s):  
High Speed ◽  
Temporal Development ◽  
Two Phase ◽  
Time Resolved ◽  
Gas Gun ◽  
Supercavitating Flow ◽  
Image Velocimetry ◽  
Spatio Temporal ◽  
Asymmetric Vortices ◽  
First Time

Supercavitation inception and formation was studied over blunt projectiles. The projectiles were fired using a gas gun method. In this method, projectiles are launched under the action of expanding detonation gases. Both qualitative and quantitative optical flow diagnostics using high speed digital imaging were used to analyze the spatio-temporal development of the supercavitating flow. For the first time, quantification of the supercavitation was achieved using Time Resolved Digital Particle Image Velocimetry (TRDPIV) detailing the two phase flow field surrounding the translating projectiles and the gas vapor bubble. Experimental results indicate that the supercavity forms at the aft end of the projectile and travels forward along the direction of projectile travel. The impulsive start of the projectile generates two asymmetric vortices which are shed from the blunt nose of the projectile. The vortices interact with the moving cavity and subsequently deform. This interaction is believed to directly contribute to the instabilities in the flight path.

scholarly journals Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
M. F. Uddin ◽  
H. Mahfuz ◽  
S. Zainuddin ◽  
S. Jeelani
Keyword(s):  
Energy Absorption ◽  
Polyurethane Foam ◽  
High Speed ◽  
Failure Modes ◽  
High Speed Camera ◽  
Test Results ◽  
Ballistic Performance ◽  
Gas Gun ◽  
Set Up ◽  
Control Samples

We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscaleTiO2particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs) in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

Conditional Moment Closure LES Modelling of an Aero-Engine Combustor at Relight Conditions

2011 ◽  
Author(s):  
Simon R. Stow ◽  
Marco Zedda ◽  
Antonios Triantafyllidis ◽  
Andrew Garmory ◽  
Epaminondas Mastorakos ◽  
...  
Keyword(s):  
Low Temperature ◽  
Flame Front ◽  
High Speed ◽  
Cfd Simulation ◽  
Moment Closure ◽  
Reactive Flow ◽  
Conditional Moment ◽  
Fuel Distribution ◽  
Conditional Moment Closure ◽  
Aero Engine

A Conditional Moment Closure (CMC) approach embedded in an LES CFD framework is presented for simulation of the reactive flow field of an aero-engine combustor operating at altitude relight conditions. Before application to the combustor geometry, the CMC model was validated on the standard lab-scale Sandia flame D. For the combustor simulation, a global mechanism for n-heptane was used along with a Lagrangian approach for the spray, to which a secondary break-up model was applied. The simulation modelled a multi-sector sub-atmospheric rig that was used to verify the altitude relight capability of the combustor. A comprehensive suite of diagnostics was applied to the rig test, including high-speed OH and kerosene PLIF as well as high speed OH* chemiluminescence. The CMC-based CFD simulation was able to predict well the position of the flame front and fuel distribution at the low pressure, low temperature conditions typical of altitude relight. Furthermore, the simulation of the ignition showed strong similarities with OH* chemiluminescence measurements of the event. An EBU-based LES was run too and showed to be unable to capture the flame front as well as the CMC model could. This work demonstrates that CMC LES can be an effective tool to support assessment of the relight capability of aero-engine combustors.

Mechanism of Parameters Variation about Electronic Components Subjected to High Impact Loads

2010 ◽  
Vol 44-47 ◽  
pp. 256-259 ◽  
Author(s):  
Bo Li ◽  
Ya Zhang ◽  
Hong Xiang Zhang
Keyword(s):  
Data Collection ◽  
Stress Level ◽  
Main Parameter ◽  
High Speed ◽  
Dynamic Testing ◽  
High Impact ◽  
Impact Loads ◽  
Electronic Components ◽  
Collection System ◽  
High Speed Data

Large quantity dynamic testing experiments are carried out to testing the parameter of electronic components in high over loading impact condition with a standard hammer machine and a high speed data collection system. And the experiments were performed for about 5000 times to more than 30 types of resistors, capacitors, transistors to test their main parameter in different stress level and fixing mode. The parameter of some electronic components appears more or less unstable, namely temporary failure, and it is sensitive to different stress level and impact direct in experiments, which can offer important value of references for reliability lifespan.

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