Damage evaluation of refractories under cyclic loading-unloading processes using ultrasonic method

Ryoichi Furushima, Yohtaro Matsuo, Tadashi Shiota, Kouichi Yasuda

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Accumulation of damage by cyclic loading-unloading under uni-axial compressive stress was evaluated using ultrasonic method for two kinds of refractories: alumina/graphite (AG) and isotropic graphite (IG) refractories. Change of relative degradation in apparent sonic velocity VRD was used for a barometer on damage evaluation of IG and AG refractories. Measurement of change in VRD actualizes in-situ evaluation of damage during loading-unloading processes. Difference of change in VRD during loading-unloading processes was observed between both specimens, which suggested the damage mechanism is different in IG and AG. Accumulation of damage for AG specimens by cyclic loading-unloading was very little, while it is a little larger for IG specimens. An increase in applied stress ratio R contributed to an increase in degree of damage accumulation. To explain the damage mechanism for both AG and IG specimens, we consider damage models, respectively. In these models, loading-unloading processes were classified into 4 steps based on the behavior of change in VRD, and damage of the two kinds of specimens was explained by relating to crack nucleation and crack opening-closing mechanism in each step.

Original languageEnglish
Pages (from-to)8652-8661
Number of pages10
JournalJournal of Materials Science
Issue number20
Publication statusPublished - Oct 2007
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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