On the Role of Laser Pulses on Spallation of Granite
| Autor: | Erich O. Ogur, S.E.M. Sebusang, R. Marumo, Rehema Ndeda |
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| Rok vydání: | 2017 |
| Předmět: |
Nuclear and High Energy Physics
Materials science 010504 meteorology & atmospheric sciences Fracture mechanics 010502 geochemistry & geophysics Laser 01 natural sciences Industrial and Manufacturing Engineering Thermal expansion law.invention Stress (mechanics) Temperature gradient Residual stress law Modeling and Simulation Fracture (geology) Forensic engineering Spallation Composite material Instrumentation 0105 earth and related environmental sciences |
| Zdroj: | Lasers in Manufacturing and Materials Processing. 4:60-75 |
| ISSN: | 2196-7237 2196-7229 |
| Popis: | Laser spallation is one of the thermal methods under study as an alternative to mechanical drilling mainly due to high power capabilities and non-contact nature. Spallation has been attributed to stress generated on the rock due to large temperature gradient and thermal expansion of the rock. It is necessary to determine the effect of pulsing of the laser as well as convective cooling on spallation, in a bid to increase the efficiency of laser spallation. In this paper, analysis of thermal stresses during pulsed laser spallation of granite is carried out. The effect of convective cooling at the end of the heating period on stress and crack propagation is also examined. A two dimensional finite element model is developed. It is observed that on cooling, tensile stresses generated during heating are inverted to compressive stresses, increasing the rate of spallation. Results also indicate that residual stresses on the rock due to pulsing are much higher. Finally, increased rate of crack propagation is observed when the rock is subjected to sudden cooling. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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