Pulsed laser generation of ultrasound in a metal plate between the melting and ablation thresholds

A. G. Every, Z. N. Utegulov, I. A. Veres

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

The generation of ultrasound in a metal plate exposed to nanosecond pulsed laser heating, sufficient to cause melting but not ablation, is treated. Consideration is given to the spatial and temporal profiles of the laser pulse, penetration of the laser beam into the sample, the evolution of the melt pool, and thermal conduction in the melt and surrounding solid. The excitation of the ultrasound takes place over a few nanoseconds, and occurs predominantly within the thermal diffusion length of a micron or so beneath the surface. Because of this, the output of the thermal simulations can be represented as axially symmetric transient radial and normal surface force distributions. The epicentral displacement response at the opposite surface to these forces is obtained by two methods, the one based on the elastodynamic Green's functions for plate geometry determined by the Cagniard generalized ray method, and the other using a finite element numerical method. The two approaches are in very close agreement. Numerical simulations are reported of the epicentral displacement response of a 3.12mm thick tungsten plate irradiated with a 4 ns pulsed laser beam with Gaussian spatial profile, at intensities below and above the melt threshold. Comparison is made between results obtained using available temperature dependent thermophysical data, and room temperature materials constants except near the melting point.

Original languageEnglish
Title of host publication41st Annual Review of Progress in Quantitative Nondestructive Evaluation, Volume 34
EditorsDale E. Chimenti, Leonard J. Bond
PublisherAmerican Institute of Physics Inc.
Pages1350-1359
Number of pages10
ISBN (Electronic)9780735412927
DOIs
Publication statusPublished - 2015
Event41st Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2014 - Boise, United States
Duration: Jul 20 2014Jul 25 2014

Publication series

NameAIP Conference Proceedings
Volume1650
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference41st Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2014
Country/TerritoryUnited States
CityBoise
Period7/20/147/25/14

ASJC Scopus subject areas

  • General Physics and Astronomy

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