Dynamic acoustoelastic testing (DAET) with a thermal strain pump for characterization of closed fatigue cracks

Prabhakaran Manogharan, Parisa Shokouhi

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Dynamic acoustoelastic testing (DAET) is a nonlinear acoustic technique used to characterize the nonlinear elastic behavior of materials. To enable the in-situ implementation of DAET, we propose a modification to the conventional DAET setup by replacing the mechanical strain pump with a thermal strain pump. This study presents the feasibility of the proposed thermal-pump DAET setup for in-situ detection of closed fatigue cracks in an aluminum test specimen. Our setup employs a hot air blower to induce a small (∼4 °C) thermal gradient near the surface of the specimen. The surface temperature evolution is captured by an infrared camera allowing thermal strain evaluation on the surface. A pair of high frequency angle-beam Rayleigh surface wave transducers are used to probe the thermal strain-induced changes in near-surface elastic properties. The slope of the relative change in Rayleigh wave speed with the applied thermal strain is taken as a measure of nonlinearity (γ) evaluated at several locations across the specimen along the intact and cracked regions. Our results show that γ measures higher near the crack and decreases as the probe moves towards the crack tip, demonstrating the potential of thermal-pump DAET for in-situ evaluation of closed fatigue cracks.

Original languageEnglish (US)
Article number102834
JournalNDT and E International
StatePublished - Jul 2023

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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