Laser non-conduction limited heating and prediction of surface recession velocity in relation to drilling

2003 ◽  
Vol 217 (9) ◽  
pp. 1067-1075 ◽  
Author(s):  
B S Yilbas ◽  
S Z Shuja
Keyword(s):  
Surface Temperature ◽  
Constant Temperature ◽  
Initial Phase ◽  
Surface Condition ◽  
Liquid Interface ◽  
Metallic Surfaces ◽  
Recoil Pressure ◽  
Recession Velocity ◽  
Evaporation Condition ◽  
Conduction Heating

Lasers find application in modifying the characteristics of metallic surfaces in industry. In the present study, a laser non-conduction heating situation is investigated and the recession velocity of the surface is computed after considering: (a) constant temperature evaporation at the surface and (b) the steady evaporation condition. It is found that, in the initial phase of evaporation, the velocity of the liquid-vapour interface (recession velocity) predicted from constant temperature evaporation at the surface condition is more realistic than that corresponding to the steady evaporation situation. Moreover, as evaporation progresses, the magnitude of the surface temperature increases because of recoil pressure developed at the vapour-liquid interface. Consequently, the surface temperature rises and the recession velocity is determined from a steady heating situation in place of that predicted from constant temperature evaporation at the surface condition.

scholarly journals Road Surface Condition Forecasting in France

2009 ◽  
Vol 48 (12) ◽  
pp. 2513-2527 ◽  
Author(s):  
L. Bouilloud ◽  
E. Martin ◽  
F. Habets ◽  
A. Boone ◽  
P. Le Moigne ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Initial Conditions ◽  
Meteorological Data ◽  
Surface Condition ◽  
Road Surface ◽  
Snow Layer ◽  
Surface Conditions ◽  
The Road ◽  
Road Surface Temperature ◽  
On The Road

Abstract A numerical model designed to simulate the evolution of a snow layer on a road surface was forced by meteorological forecasts so as to assess its potential for use within an operational suite for road management in winter. The suite is intended for use throughout France, even in areas where no observations of surface conditions are available. It relies on short-term meteorological forecasts and long-term simulations of surface conditions using spatialized meteorological data to provide the initial conditions. The prediction of road surface conditions (road surface temperature and presence of snow on the road) was tested at an experimental site using data from a comprehensive experimental field campaign. The results were satisfactory, with detection of the majority of snow and negative road surface temperature events. The model was then extended to all of France with an 8-km grid resolution, using forcing data from a real-time meteorological analysis system. Many events with snow on the roads were simulated for the 2004/05 winter. Results for road surface temperature were checked against road station data from several highways, and results for the presence of snow on the road were checked against measurements from the Météo-France weather station network.

Elastic, Plastic Stresses in Free Plate With Periodically Varying Surface Temperature

1958 ◽  
Vol 25 (4) ◽  
pp. 603-606
Author(s):  
Halil Yüksel
Keyword(s):  
Steady State ◽  
Surface Temperature ◽  
Constant Temperature ◽  
Thermal Stresses ◽  
Plastic Material ◽  
The Other ◽  
Perfectly Plastic ◽  
Temperature Oscillations ◽  
Steady State Temperature ◽  
Elastic Perfectly Plastic

Abstract The paper is concerned with a free plate that consists of an elastic, perfectly plastic material and is subjected to a harmonically varying temperature at one face, while the other face is kept at a constant temperature and the edge is perfectly insulated. The thermal stresses associated with the steady-state temperature oscillations are analyzed, and the development of plastic regions is discussed.

Transient Thermal Stresses in Cylindrically Orthotropic Composite Tubes

1989 ◽  
Vol 56 (2) ◽  
pp. 411-417 ◽  
Author(s):  
G. A. Kardomateas
Keyword(s):  
Circular Cylinder ◽  
Surface Temperature ◽  
Constant Temperature ◽  
Material Properties ◽  
Thermal Stresses ◽  
The Other ◽  
The One ◽  
Displacement Approach ◽  
Transient Thermal ◽  
Cylindrically Orthotropic

A solution is given for the stresses and displacements in an orthotropic, hollow circular cylinder, due to an imposed constant temperature on the one surface and heat convection into a medium of a different constant temperature at the other surface. Temperature-independent material properties are assumed and a displacement approach is used. Results for the variation of stresses with time and through the thickness are presented.

Influence of layers on flexural motion of a multilayer assembly due to the laser ablation process

2003 ◽  
Vol 217 (8) ◽  
pp. 945-954 ◽  
Author(s):  
B S Yilbas ◽  
J Hyder
Keyword(s):  
Equivalent Stress ◽  
Substrate Material ◽  
Liquid Interface ◽  
Flexural Wave ◽  
Maximum Magnitude ◽  
Pressure Loading ◽  
Maximum Displacement ◽  
Recoil Pressure ◽  
Laser Ablation Process ◽  
Maximum Equivalent Stress

Laser-induced evaporation results in recoil pressure at the vapour-liquid interface, which in turn gives rise to flexural wave generation in the substrate material due to impact pressure loading at the interface. In the present study, recoil pressure due to laser non-conduction limited heating is formulated and because of pressure loading at the vapour-liquid interface the flexural motion of the substrate material is modelled. A multilayer cantilever arrangement of the workpiece, consisting of layers of steel and Inconel alloy, is considered. In order to investigate the influence of the number of layers on the resulting flexural motion and stress fields, four cases and three layer arrangements are taken into account. It is found that the maximum displacement in the order of 10-4m occurs while the maximum equivalent stress is about 20 MPa. The maximum magnitude of shear stress is higher than that of equivalent stress.

scholarly journals Coating Metallic Surfaces in Engineering Applications for Improved Performance

2020 ◽  
Vol 9 (4) ◽  
pp. 1743-1746
Keyword(s):  
Surface Temperature ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Coefficient Of Thermal Expansion ◽  
Combustion Engines ◽  
Metallic Surfaces ◽  
Combustion Chambers ◽  
Engineering Applications ◽  
Coating Materials ◽  
Improved Performance

This paper explains the various types of coatings which include metals, polymers, aerogels and ceramics coatings applied on metal surfaces through different methods so as to prevent oxidation, corrosion, cracking, wear and increase surface temperature. Coatings are covering layers applied to metallic surfaces in engineering applications so as to improve performance. They serve as protection to the underlying material. Literatures had it that coating applied in automobile and stationary engines, gas turbines and other internal combustion engines has helped to increase their brake thermal efficiencies. This happened because of increased surface temperature achieved in the combustion chambers due to low thermal conductivity and matched coefficient of thermal expansion of the coating materials.

Paper 1: Application of Friction and Wear Results Obtained on a Pin–Disc Machine to the Ring–Traveller Problem

1967 ◽  
Vol 182 (14) ◽  
pp. 1-10
Author(s):  
D. G. Powell ◽  
S. W. E. Earles
Keyword(s):  
Wear Rate ◽  
Surface Temperature ◽  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Surface Condition ◽  
Surface Films ◽  
Ring Radius ◽  
The Coefficient Of Friction ◽  
Steel Surfaces ◽  
Disc Configuration

An experimental study of the dependence of the coefficient of friction and rate of wear of unlubricated steel surfaces in a pin–disc configuration has suggested the use of certain parameters involving normal force, N, and sliding speed, U, in correlating the effects of surface temperature and surface condition with both friction and wear. The interpretation of these functions in terms of the parameters of the ring–traveller problem suggests that the coefficient of friction can be expressed as a function of U2 √(traveller mass/ring radius) and the traveller wear rate is directly proportional to √ (traveller mass/ring radius) providing that sliding conditions are chosen to produce a constant value of surface temperature. This last conclusion is restricted by the previous observation that beyond a certain critical temperature periodic removal of the self-generated surface films occurs. This causes a large increase in the values of both coefficient of friction and wear rate and it is suggested therefore that the ‘temperature instability’ of the surface oxide films may possibly be the prime cause of excessive yarn breakages, and overheated travellers after long periods of operation. An end-breakage criterion is proposed. Previously published results of the friction and wear measured in ring–traveller mechanisms are re-interpreted in the light of the parameters suggested by the present work.

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