MULTIFREQ UENCY ACOUSTIC EMISSIONS (AE) FOR MONITORING THE TIME EVOLUTION OF MICROPROCESSES WITHIN SOLIDS
Gabriele Paparo and Giovanni P. Grcgori
Istituto di Acustica "O. M. Corbino", CNR, via Fosso dcl Cavaliere 100, 00133 Roma
Microprocesses occur like chain rcact ions where bonds progressively yicld. The tempora! evolut ion can be tracked by multifrequcncy AE . Two principle ideas. Onc rclies on time series of A E of increasingly lower frequency.Thc sccond compares time histories of cvcry AE event (fix.ed frequency) with a lognormal distribution: dcviations revcal additional paramcters, and the tail results modulated by cxtemal effccts, cnvisaging what triggers evcry AE . Natural environmental phcnomcna are effcctive feasibility tests, for subsequent laboratory implementati on.