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1987
Journal Article
Titel
Basic principles for testing ceramic-bonded grinding wheels by acoustic emission analysis.
Alternative
Grundlagen zur Pruefung von keramisch gebundenen Schleifscheiben mittels Schallemissionsanalyse
Abstract
The investigations were aimed at determining the causal relation between the size of a formed crack and the amount of acoustic energy emitted during its formation, as well as between the size of the crack and the residual strength of a ceramic-bonded grinding wheel material, i.e. its time to failure under constant load conditions. With regard to the correlation between crack size and acoustic emission the area of the crack was shown to be proportional to the amount of acoustic energy emitted during its formation. The laws of linear-elastic fracture mechanics apply to the subject grinding wheel material. The relationship between acoustic emission and the residual strength, or time to failure, of bend test bars was derived on the basis of the determined proportionality constants and material parameters. The derived formulae indicate the residual strength level or time to failure to be anticipated, when a certain amount of acoustic energy is emitted during overspeed testing. Experiments i nvolving artificially induced cracks were conducted as a means of verifying the correctness of the theoretically determined correlation. These results demonstrate conclusively that AEA enables the reliable detection of strength-reducing crack formation and hence, that is suitable for use in the testing of grinding wheels. Combining AEA with a proof test yields a new concept for the testing of grinding wheels. The results were obtained on a particular type of grinding wheel that satisfied all preconditions with regard to characterization via unequivocal material constants.