Preface ........................................................ xi
Acknowledgement .............................................. xiii
1 Introduction to Laser Heating Process ...................... 1
References ................................................. 5
2 Conduction-Limited Laser Pulsed Laser Heating:
Fourier Heating Model ...................................... 7
2.1 Introduction to Heat Generation Due to Absorption of
Incident Laser Beam ........................................ 7
2.2 Temperature Field Due to Laser Step Input Pulse Heating ... 10
2.2.1 Insulated Boundary Condition at the Surface ........ 11
2.2.1.1 Step Input Pulse Heating without Cooling
Cycle ..................................... 11
2.2.1.2 Step Input Pulse Heating Including
Heating and Cooling Cycles ................ 14
2.2.1.3 Exponential Pulse Heating ................. 18
2.2.2 Convective Boundary Condition at the Surface ....... 23
2.2.2.1 Step Input Pulse Heating Including
Heating and Cooling Cycles ................ 23
2.2.2.2 Exponential Pulse Heating ................. 31
2.3 Thermal Efficiency of Heating Process ..................... 35
2.4 Results and Discussion .................................... 38
2.4.1 Step Input Pulse Heating without Cooling Cycle:
Insulated Boundary Condition at the Surface ........ 39
2.4.2 Step Input Pulse Heating Including Heating and
Cooling Cycles: Insulated Boundary Condition at
the Surface ........................................ 40
2.4.3 Exponential Pulse Heating: Insulated Boundary
Condition at the Surface ........................... 42
2.4.4 Step Input Pulse Heating Including Heating and
Cooling Cycles: Convective Boundary Condition
at the Surface ..................................... 44
2.4.5 Exponential Pulse Heating: Convective Boundary
Condition at the Surface ........................... 45
2.4.6 Thermal Efficiency of Heating Process .............. 47
References ................................................ 50
3 Nonconduction-Limited Pulsed Laser Heating: Fourier
Heating Model ............................................. 53
3.1 Introduction to Nonconduction-Limited Heating ............. 53
3.2 Step Input Pulse Heating: Melting and Evaporation at the
Surface ................................................... 54
3.2.1 Consideration of Steady Recession of the
Irradiated Surface ................................. 54
3.2.2 Transient Analysis of Evaporation at the Surface ... 62
3.3 Exponential Pulse Heating: Evaporation at the Surface ..... 74
3.4 Time Integration of Heating ............................... 89
3.5 Two-Dimensional Heating .................................. 100
3.5.1 Transient Evaporation ............................. 100
3.5.2 Stationary Source at the Surface .................. 103
3.5.3 Moving Heat Source at the Surface ................. 104
3.6 Entropy Generation Due to Laser Pulse Heating ............ 106
3.7 Results and Discussion ................................... 112
3.7.1 Step Input Pulse Heating: Melting and Evaporation
at the Surface .................................... 112
3.7.2 Consideration of Steady Recession of the
Irradiated Surface ................................ 112
3.7.3 Transient Analysis of Evaporation at the Surface .. 113
3.7.4 Exponential Pulse Heating: Evaporation at the
Surface ........................................... 116
3.7.5 Time Integration of Heating ....................... 119
3.7.6 Two-Dimensional Heating: Transient Heating ........ 120
3.7.7 Entropy Generation during Laser Heating ........... 121
References ............................................... 123
4 Laser Cutting Process .................................... 125
4.1 Introduction to Laser Cutting ............................ 125
4.2 Closed-Form Solution to Laser Cutting Process ............ 126
4.3 Lump Parameter Analysis for Cutting Process .............. 131
4.3.1 Formulation of Kerf Width Size .................... 131
4.3.2 Thermal Efficiency of Laser Cutting Process ....... 134
4.3.3 Estimation of Liguid Layer Thickness .............. 136
4.4 Analysis for Heat Transfer to Liquid Metals with
Presence of Assisting Gas ................................ 144
4.5 Results and Discussion ................................... 148
4.5.1 Closed-Form Solution for Laser Cutting Process .... 148
4.5.2 Formulation of Kerf Width Size .................... 150
4.5.3 Thermal Efficiency of Laser Cutting Process ....... 154
4.5.4 Liquid Layer Thickness ............................ 157
4.5.5 Heat Transfer to Liquid Metal with the Presence of
Assisting Gas ..................................... 159
References ............................................... 161
5 Thermal Stress Analysis .................................. 163
5.1 Introduction ............................................. 163
5.2 Step Input Pulse and Thermal Stress ...................... 164
5.2.1 Insulated Boundary Condition at the Surface ....... 164
5.2.2 Stress Continuity at the Surface .................. 173
5.2.3 Step Input Pulse Heating Including Heating and
Cooling Cycles and Thermal Stresses ............... 176
5.3 Exponential Pulse Heating and Thermal Stress ............. 190
5.3.1 Thermally Insulated Boundary Condition at the
Surface and Thermal Stress Analysis ............... 191
5.3.2 Convection Boundary at the Surface and Thermal
Stress Analysis ................................... 198
5.4 Exponential Pulse Heating and Thermal Stresses - Elasto-
Plastic Analysis ......................................... 216
5.4.1 Formulation of Recoil Pressure .................... 217
5.4.2 Formulation of Stress Distribution ................ 221
5.5 Thermal Stress and Entropy Generation Due to Exponential
Pulse Heating ............................................ 225
5.6 Results and Discussion ................................... 230
5.6.1 Stress Free Surface Condition ..................... 230
5.6.2 Zero Stress Gradient at the Surface ............... 233
5.6.3 Laser Step Input Heating and Thermal Stress
Development ....................................... 236
5.6.4 Time Exponentially Pulse Heating and Thermal
Stress Development ................................ 239
5.6.5 Thermally Insulated Surface ....................... 239
5.6.6 Convection Boundary at the Surface ................ 241
5.6.7 Thermal Stress Development due to Laser
Exponential Pulse - Elasto-Plastic Analysis ....... 243
5.6.8 Thermal Stresses and Entropy Generation due to
Laser Exponential Pulse Heating ................... 246
References ............................................... 249
6 Laser Short-Pulse Heating: Nonequilibrium Energy
Transfer ................................................. 251
6.1 Introduction to Nonequilibrium Heating ................... 251
6.2 Exact Solution of Cattaneo's Equation .................... 252
6.2.1 Derivation of Cattaneo's Equation from Boltzmann's
Transport Equation ................................ 253
6.2.2 Analytical Solution of Cattaneo's Equation -
Surface Heat Source ............................... 257
6.2.3 Analytical Solution of Cattaneo's Equation -
Volumetric Heat Source ............................ 259
6.3 Laser Short-Pulse Heating and Application of
Perturbation Method ...................................... 263
6.3.1 Application of Perturbation Method - Surface Heat
Source ............................................ 263
6.3.2 Application of Perturbation Method - Volumetric
Heat Source ....................................... 267
6.4 Application of Symmetries and Similarity Transformation
to Laser Short-Pulse Heating ............................. 271
6.4.1 Perturbation Solution ............................. 274
6.4.2 A Boundary-Value Problem and Time Condition ....... 275
6.5 Application of Lie Point Symmetry Solution to Laser
Short-Pulse Heating ...................................... 276
6.6 Results and Discussion ................................... 283
6.6.1 Exact Solution of Cattaneo's Equation ............. 284
6.6.1.1 Surface Heat Source Model ................ 284
6.6.1.2 Volumetric Heat Source Model ............. 284
6.6.2 Laser Short-Pulse Heating and Perturbation Method . 286
6.6.2.1 Surface Heat Source Model ................ 286
6.6.2.2 Volumetric Source ........................ 289
6.6.3 Lie Point Symmetry Solution for Laser Short-Pulse
Heating ........................................... 291
References ............................................... 293
Index ......................................................... 295
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