Acoustic Emission: Establishing the Fundamentals

Abstract

In the mid-1970's a program of fundamental research was initiated at NBS to improve the scientific understanding of acoustic emission. Many individual results of this research have been reported in the literature and are beginning to be incorporated in a new generation of acoustic emission instrumentation, in improved test methodologies, and in the analysis of data. Here, we summarize the problems faced by acoustic emission <{llidway through the last decade, review the accomplishments of the NBS program and related research programs, and outline the research that will be required in future years.

Analysis of the bending fracture process for piezoelectric composite actuators using dominant frequency bands by acoustic emission

“…Acoustic emission (AE) [1,2] is defined as the generation of stress or elastic waves when stored energy is instantly released from localized sources within a material under external loadings such as static, dynamic, impact and thermal. It is well known that matrix crack and deformation, fiber-matrix debonding, fiber breakage and ply delamination are representative sources of emission in composite materials.…”

Statistical fracture of E-glass fibres using a bundle tensile test and acoustic emission monitoring

“…AE technique is a non-destructive method at damage evaluation [22][23][24], that uses stress waves emitted by stressed material undergoing deformation processes as plastic deformation or crack growth. As an elastic wave or AE signal travels through a material, its characteristics are constantly changing due to damping, boundary surface interactions, etc.…”

Optimization of Acoustic Emission Data Clustering by a Genetic Algorithm Method

“…In order to take into account that the principal components do not contain the same quantity of information, the distance between two points in this j D-space was defined as 2 where λ i is the ith eigenvalue, X i and Y i are the ith coordinates of the vectors X and Y . The distance d 2 w is a squared weighted Euclidean distance, used in all the following steps.…”

“…Beyond the characterization of damage, the current challenge is to predict structures lifetime. To achieve this goal, a quantification of damage is needed but so is an identification of the various damage mechanisms, for which acoustic emission (AE) [1,2] is a suitable technique. Acoustic emission is composed of transient waves resulting from the sudden release of stored energy during a damage process.…”