POWER CONSIDERATIONS IN ACOUSTIC-EMISSION

In stochastic acoustic emission, both theory and experiments suggest t hat the power of the acoustic emission signal is proportional to the s ource energy. Hence, inference about the power is equivalent to infere nce about the source energy except for a constant multiple. In this re gard, the connection between peaks exceeding a fixed level and the pow er in random acoustic emission waves is explored when the source energ y is an impulse of short duration. Under certain conditions, the peak distribution is sensitive to power changes, determines it, and is dete rmined by it. The maximum-likelihood estimator of the power from a ran dom sample of peaks-the peak estimator-is more efficient than the maxi mum-likelihood estimator-average sum of squares-from a random sample o f the same size of signal values. When evaluated from nonrandom sample s, indications are that the peak estimator may still have a relatively small mean-square error. A real data example indicates that the left- truncated Rayleigh probability distribution may serve as an adequate m odel for high peaks. (C) 1995 Acoustical Society of America.