Selection of Scuffing-Resistant Materials Under Lubricated, High-Speed Sliding

1988 ◽  
Vol 140 ◽  
Author(s):  
J. J. Au ◽  
M. W. Corcoran ◽  
J.-Y. Yung
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Wear Tests ◽  
Selection Of ◽  
Good Agreement

AbstractThe scuffing resistance of materials under lubricated high-speed sliding was analyzed based on the thermalelastic instability (TEl) model. The model was used to select and rank scuffing-resistant materials.The scuffing resistance was also determined experimentally by the Falex 6 thrust washer wear tests. There was good agreement between the experimental results and the analytical predictions.

Determination of the limits of stable combustion at high supersonic flow velocities in a channel

2010 ◽  
Vol 3 (2) ◽  
pp. 47-60
Author(s):  
Alexey V. Starov
Keyword(s):  
Paper Analysis ◽  
Measurement Methods ◽  
Experimental Results ◽  
Physical Parameters ◽  
Supersonic Speed ◽  
Combustion Limits ◽  
Criterial Description ◽  
Selection Of ◽  
Good Agreement

In this paper, analysis of existing methods application of criterial description of ignition conditions and combustion break-out for summarizing of experimental results is carried out. Experimental results are obtained at investigations of hydrogen combustion in combustor with high supersonic speed of airflow. For these conditions selection of several criterions was substantiated and they have a good agreement with new experimental results. At the same time complexity of determination of experimental physical parameters, which are included in criterions, do not allow confidently to apply them for prediction of steady-state combustion limits. Therefore further accumulation of experimental data and development of measurement methods are necessary for accurate criterions obtaining.

scholarly journals Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

2016 ◽  
Vol 61 (2) ◽  
pp. 1003-1008 ◽  
Author(s):  
A. Dziubińska ◽  
A. Gontarz ◽  
K. Dziedzic
Keyword(s):  
Qualitative Research ◽  
Finite Element ◽  
Magnesium Alloy ◽  
Numerical Results ◽  
Experimental Results ◽  
Az31 Magnesium Alloy ◽  
Forming Process ◽  
Closed Die Forging ◽  
Selection Of ◽  
Good Agreement

AbstractThe paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

Surface Roughness Effects in High-Speed Hydrodynamic Journal Bearings

1997 ◽  
Vol 119 (4) ◽  
pp. 776-780 ◽  
Author(s):  
H. Hashimoto
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Reynolds Equation ◽  
Computation Time ◽  
Experimental Results ◽  
Roughness Effects ◽  
Modified Reynolds Equation ◽  
Nonlinear Simultaneous Equations ◽  
Theoretical Results ◽  
Good Agreement

This paper describes an applicability of modified Reynolds equation considering the combined effects of turbulence and surface roughness, which was derived by Hashimoto and Wada (1989), to high-speed journal bearing analysis by comparing the theoretical results with experimental ones. In the numerical analysis of modified Reynolds equation, the nonlinear simultaneous equations for the turbulent correction coefficients are greatly simplified to save computation time with a satisfactory accuracy under the assumption that the shear flow is superior to the pressure flow in the lubricant films. The numerical results of Sommerfeld number and attitude angle are compared with the experimental results to confirm the applicability of the modified Reynolds equation in the case of two types of bearings with different relative roughness heights. Good agreement was obtained between theoretical and experimental results.

High-speed water jets from vertically accelerated rotating cones

1973 ◽  
Vol 60 (4) ◽  
pp. 703-719
Author(s):  
P. Savic ◽  
J. D. Allan ◽  
G. P. Van Blokland
Keyword(s):  
Explosive Charge ◽  
High Speed ◽  
Order Theory ◽  
Experimental Results ◽  
Viscous Drag ◽  
First Order ◽  
First Order Theory ◽  
Water Jets ◽  
Rotating Cone ◽  
Good Agreement

Water jets are produced by vertically accelerating a rotating cone partially filled with water. It is shown that the acceleration of the parabolic meniscus results in a motion similar to that observed in a shaped explosive charge (Monroe jet). Acceleration of the cone is effected by means of an inductive electromagnetic accelerating device (conical pinch) whose theory is developed in terms of the WKB approximation. A second-order inviscid theory for the motion of the fluid in the cone in terms of the Penney-Price linearization procedure is presented and it is shown that good agreement for the jet head velocity can be achieved for low velocities. At higher velocities, experimental results appear to lag behind the theoretical ones, probably owing to the dispersal of the jet head through viscous drag with the surrounding atmosphere. The shape of the jet at early times is well represented by first-order theory.

Experimental Studies on Flexure Pivot Tilting Pad Gas Bearings With Pad Radial Compliance

2007 ◽  
Author(s):  
Kyuho Sim ◽  
Aaron Rimpel ◽  
Daejong Kim
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Experimental Results ◽  
Frequency Dependent ◽  
Gas Bearings ◽  
Force Coefficients ◽  
Tilting Pad ◽  
Operation Frequency ◽  
Large Rotor ◽  
Good Agreement

This paper presents experimental studies on imbalance responses of a rotor supported by two flexure pivot tilting pad gas bearings with radial compliance. The radial compliance was aimed to accommodate large rotor centrifugal growth inherent with high speed operation. Frequency-dependent rotordynamic force coefficients calculated from developed software were used to predict critical speeds and onset speed of instability and compared with experimental results. Two results show very good agreement.

Numerical Simulation of Dynamic Response of Planing Craft Sailing in Calm Water

2014 ◽  
Vol 590 ◽  
pp. 37-41
Author(s):  
Yu Min Su ◽  
Yun Hui Li ◽  
Hai Long Shen
Keyword(s):  
Numerical Simulation ◽  
Empirical Formula ◽  
High Speed ◽  
Evaluation Method ◽  
Simulation Method ◽  
Experimental Results ◽  
Planing Craft ◽  
Calm Water ◽  
Performance Evaluation Method ◽  
Good Agreement

In order to forecast the sailing response of planing craft at high speed rapidly and accurately, CFD code Fine/Marine solver was used to calculate the resistance and sailing attitude of a high-speed planing craft, then the numerical results were compared with experimental results and empirical formula results. The results showed that resistance error calculated by Fine/Marine was between 5% and 10%, trim and heave results were in good agreement with experimental results, and had greater accuracy compared with the empirical formula results. The feasibility of this numerical simulation method was validated and this method provided an effect performance evaluation method for new designing planing crafts.

Experimental Researches on Detonation of Aluminized Explosives to High-Speed Flyer Impact

2010 ◽  
Vol 152-153 ◽  
pp. 713-716
Author(s):  
Jian Bing Men ◽  
Jian Wei Jiang ◽  
Shu You Wang
Keyword(s):  
Experimental Data ◽  
Plane Wave ◽  
Statistical Method ◽  
Structural Design ◽  
High Speed ◽  
Critical Thickness ◽  
Experimental Results ◽  
Wave Loads ◽  
Experimental Researches ◽  
Selection Of

In present paper, aluminized explosives with separator inside are detonated by plane wave loads from metal flyer impacts. Four types of aluminized explosives(THAL、H-6、HBX-1、HBX-3) that used widely in warheads are test experimentally in order to obtain the critical thickness of separator(thicknesses L50-50% possibility of detonating). The critical separator thicknesses of detonating four types of aluminized explosives are calculated through statistical method according to experimental data. Stability sequence for these four explosive were determinate according to anti-detonation capability. The experimental results provided reference for the selection of explosive and structural design of warhead.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

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