Accession Number : ADA265743


Title :   Characterization of Acoustic Emission Source to Identify Fracture in Concrete


Descriptive Note : Final rept. Dec 89-Nov 92,


Corporate Author : NORTHWESTERN UNIV EVANSTON IL DEPT OF CIVIL ENGINEERING


Personal Author(s) : Shah, Surendra P


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a265743.pdf


Report Date : 01 Apr 1993


Pagination or Media Count : 81


Abstract : This report describes the theoretical basis, experimental approaches, and results of research to evaluate fracture properties of concrete using quantitative acoustic emission (AE) analysis techniques. Analytical tools were developed to process AE data. These tools included improvements in P-wave arrival analysis, AE source location calculation, and multichannel deconvolution techniques. The microfracture characteristics of mortar was evaluated using a three dimensional moment tensor analysis. Microcracking was found to be primarily mixed mode and shear. A new technique for testing concrete in uniaxial tension was developed. Using this technique localization and strain-softening behavior was examined. Microcracking was found to be evenly distributed throughout the specimen until about 80% of peak load. At this point localization began and the microcracks coalesced into a single macrocrack.... Acoustic emission, Microcracking, Quasi-brittle materials, Damage localization.


Descriptors :   *CONCRETE , *FRACTURE(MECHANICS) , *MICROCRACKING , *ACOUSTIC EMISSIONS , DAMAGE , NONDESTRUCTIVE TESTING , THREE DIMENSIONAL , SHEAR STRESSES , MULTICHANNEL , SOFTENING , TENSOR ANALYSIS , MORTARS , TENSORS , TENSION , BRITTLENESS , DAMAGE ASSESSMENT , ACOUSTIC DETECTION , MOMENTS


Subject Categories : Ceramics, Refractories and Glass
      Acoustic Detection and Detectors


Distribution Statement : APPROVED FOR PUBLIC RELEASE