Improved interpretation of vibration responses from concrete delamination defects using air-coupled impact resonance tests

Taekeun Oh, John S Popovics, Suyun Ham, Sung Woo Shin

Research output: Contribution to journalArticle

Abstract

The deteriorating national infrastructure demands improved nondestructive evaluation (NDE) and structural health monitoring methods for existing concrete structures. Vibration resonance tests offer an efficient NDE method to identify and characterize shallow (near-surface) delamination defects that afflict RC structures. However, efficient implementation of effectivemodal analysis methods for this purpose is hindered by practical testing limitations. This paper studies vibration resonance data fromsquare, rectangular, and circular near-surface delamination defects in concrete using two testing configurations: a coupled source-receiver set configuration (driving point type),which is analogous to the impact-echo (IE) test, and a fixed-source moving sensor configuration, which represents a conventional modal analysis test. Alldata were collected using contactless air-coupled sensors, which enable efficient data collection from large structures from prepared laboratory samples. An approach to selfnormalize each IEdata set using surface wave pulse information in the time signal is proposed. The self-normalizedmultipoint IE data are presented in the form of modal images, where overlap of the first few natural mode shapes accurately predicts the areal size of underlying delamination defects.Themode shapes obtainedwith the correctedmultipoint IEtesting configuration,which provides a significant advantage for the application in NDE tests because damage location, size, and shape need not be known in advance, compare favorably with those from conventional modal testing.

Original languageEnglish (US)
Pages (from-to)315-324
Number of pages10
JournalJournal of Engineering Mechanics
Volume139
Issue number3
DOIs
StatePublished - Jul 5 2013

Keywords

  • Air-coupled sensing
  • Delamination defect detection
  • Driving point frequency response function (FRF)
  • Impact-echo method
  • Modal parameter estimation
  • Modal testing
  • Vibration of delamination defect

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering

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