scholarly journals Generalized Thermoelastic Functionally Graded on a Thin Slim Strip Non-Gaussian Laser Beam

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1094 ◽  
Author(s):  
Sayed M. Abo-Dahab ◽  
Ahmed E. Abouelregal ◽  
Marin Marin
Keyword(s):  
Laser Beam ◽  
Pulse Length ◽  
Generalized Thermoelasticity ◽  
Functionally Graded ◽  
Strong Impact ◽  
Problem Solution ◽  
Gaussian Laser Beam ◽  
Laser Parameters ◽  
Non Gaussian ◽  
The Impact

The present study utilizes the generalized thermoelasticity theory, with one thermal relaxation time (TR), to examine the thermoelastic problem of a functionally graded thin slim strip (TSS). The authors heated the plane surface bounding using a non-Gaussian laser beam with a pulse length of 2 ps. The material characteristics varied continually based on exponential functions. Moreover, the equations governing the generalized thermoelasticity for a functionally graded material (FGM) are recognized. The problem’s ideal solution was primarily obtained in the Laplace transform (LT) space. The LTs were converted numerically because of the considerable importance of the response in the transient state. For a hypothetical substance, the numerical procedures calculating the displacement, stress, temperature and strain were given. The analogous problem solution to an isotropic homogeneous material was provided by defining the parameter of non-homogeneity adequately. The obtained results were displayed using graphs to illustrate the extent to which non-homogeneity affected displacement, stress, temperature and strain. A comparison was been made between the present study and those previously obtained by others, when the new parameters vanish to show the impact of the non-homogeneity, TSS and laser parameters on the phenomenon. The results obtained indicate a significant strong impact of FGM, TSS and laser parameters.

scholarly journals Combined effect of relativistic and ponderomotive nonlinearity on self-focusing of Gaussian laser beam in a cold quantum plasma

2016 ◽  
Vol 34 (3) ◽  
pp. 426-432 ◽  
Author(s):  
H. Kumar ◽  
M. Aggarwal ◽  
Richa ◽  
T.S. Gill
Keyword(s):  
Laser Beam ◽  
Beam Width ◽  
Combined Effect ◽  
Quantum Plasma ◽  
Gaussian Laser Beam ◽  
Relativistic Case ◽  
Self Focusing ◽  
Ponderomotive Nonlinearity ◽  
Paraxial Ray ◽  
The Impact

AbstractIn the present paper, we have investigated self-focusing of Gaussian laser beam in relativistic ponderomotive (RP) cold quantum plasma. When de Broglie wavelength of charged particles is greater than or equal to the inter particle distance or equivalently the temperature is less than or equal to the Fermi temperature, quantum nature of the plasma constituents cannot be ignored. In this context, we have reported self-focusing on account of nonlinear dielectric contribution of RP plasma by taking into consideration the impact of quantum effects. We have setup the nonlinear differential equation for the beam-width parameter by paraxial ray and Wentzel Kramers Brillouin approximation and solved it numerically by the Runge Kutta Fourth order method. Our results show that additional self-focusing is achieved in case of RP cold quantum plasma than relativistic cold quantum plasma and classical relativistic case. The pinching effect offered by quantum plasma and the combined effect of relativistic and ponderomotive nonlinearity greatly enhances laser propagation up to 20 Rayleigh lengths.

Modeling and Characterization of Laser Drilling of Small Holes on Metal Sheets

2004 ◽  
Author(s):  
Wei Han ◽  
Ryszard J. Pryputniewicz
Keyword(s):  
Laser Beam ◽  
Manufacturing Industry ◽  
Pulse Length ◽  
Experimental Studies ◽  
Laser Drilling ◽  
Melting Front ◽  
Laser Parameters ◽  
Metal Sheets ◽  
Small Holes ◽  
Melt Ejection

Laser drilling is increasingly being used in fabrication of small components in various materials with applications in aerospace, automotive, electronics and medical industries, and it offers a unique combination of benefits for the contemporary manufacturing industry as a rapid, precise, clean, flexible, and efficient process. Laser drilling involves a stationary laser beam which uses its high power density to melt or vaporize material from the workpiece, and the process is governed by an energy balance between the irradiating energy from the laser beam, the conduction heat into the workpiece, the energy losses to the environment, and the energy required for phase change in the workpiece. There are three major mechanisms of removal of material from the beam interaction zone and consequent propagation of the melt front into the metal bulk. They are (1) melt ejection due to interaction between the melt and an assisting gas, (2) melt ejection by the vaporization-induced recoil force, and (3) melt evaporation. The results of laser drilling processes, such as the profile of the heat affected zone (HAZ) and the geometry of the holes, strongly depend on settings of the laser parameters such as peak power, pulse length, pulse repetition rate, number of pulses, focal condition, etc. In addition, the processing results are strongly influenced by geometrical and material properties of the workpiece. This paper presents theoretical and experimental studies of laser drilling of micrometer size holes on metal sheets using a pulsed Nd:YAG laser. A model of the temperature distribution and the motion of the melting front for laser drilling is presented and compared with experimental data. Effects of laser parameters on the resultant geometry of the hole are investigated and summarized, and an optimum procedure for laser drilling of small holes on metal sheets is outlined.

EFFECTS OF COMBINED RADIATIVE AND CONVECTIVE HEAT TRANSFER ON TEMPERATURE BENEATH MODULATED SOURCE

2007 ◽  
Vol 21 (11) ◽  
pp. 1903-1913 ◽  
Author(s):  
KAREM BOUBAKER ◽  
M. BOUHAFS
Keyword(s):  
Heat Transfer ◽  
Analytical Solution ◽  
Laser Beam ◽  
Heat Equation ◽  
Convective Heat Transfer ◽  
Temperature Profile ◽  
Convective Heat ◽  
Calculation Method ◽  
Gaussian Laser Beam ◽  
Non Gaussian

An analytical solution is presented to the heat equation in the vicinity of a surface fluid, heated by a modulated Gaussian Laser beam and taking into account three heat transfer modes: conduction, radiation and convection. A new calculation method is performed for profiling temperature inside a surface fluid. Comparison with several experimental profiles explains some unexpected temperature profile results as non-Gaussian behaviour.

scholarly journals Spatial evolution of a q-Gaussian laser beam in relativistic plasma

2010 ◽  
Vol 28 (3) ◽  
pp. 479-489 ◽  
Author(s):  
A. Sharma ◽  
I. Kourakis
Keyword(s):  
Laser Beam ◽  
Beam Profile ◽  
Relativistic Plasma ◽  
Gaussian Laser Beam ◽  
Transverse Beam ◽  
Recent Experimental Study ◽  
Gaussian Profile ◽  
Spatial Beam ◽  
Gaussian Distribution Function ◽  
Non Gaussian

AbstractIn a recent experimental study, the beam intensity profile of the Vulcan petawatt laser beam was measured; it was found that only 20% of the energy was contained within the full width at half maximum of 6.9 μm and 50% within 16 μm, suggesting a long-tailed non-Gaussian transverse beam profile. A q-Gaussian distribution function was suggested therein to reproduce this behavior. The spatial beam profile dynamics of a q-Gaussian laser beam propagating in relativistic plasma is investigated in this article. A non-paraxial theory is employed, taking into account nonlinearity via the relativistic decrease of the plasma frequency. We have studied analytically and numerically the dynamics of a relativistically guided beam and its dependence on the q-parameter. Numerical simulation results are shown to trace the dependence of the focusing length on the q-Gaussian profile.

Propagation of a Non-Gaussian Laser Beam in SELFOC Fibres

1977 ◽  
Vol 24 (11) ◽  
pp. 1141-1146
Author(s):  
V.P. Nayyar ◽  
N.K. Verma
Keyword(s):  
Laser Beam ◽  
Gaussian Laser Beam ◽  
Non Gaussian
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