INFLUENCE OF PARAMETERS OF PARTICLE IMPACT ON SHAPE OF ACOUSTIC EMISSION SIGNAL

One of the possible methods for generation of AE signal for non-destructive testing is an application of striking particles on device under test. Impacting particles generate an impulse AE, which is spreading by material of device. The state of the material is evaluated by sensing of AE signal at different locations on verified subject. For defectoscopic analysis it is useful to have the opportunity to influence the generated signal. The theory of impact implies that changes of the signal may be achieved by changing the parameters of impact (particle size and velocity, specific mass of the materials, elastic modulus and Poisson's constant of materials). The paper is therefore aimed at assessing the practical research of the influence of the impact parameters on the frequency spectrum of AE signal. Furthermore, comparison to theoretical knowledge was performed. The research was focused on the study of composition of the mixture created from particles of two different granularities. It also deals with the predictability of the shape of the spectrum AE signal and finding appropriate statistical parameters of AE, which are associated with parameters of impact and which can be used for this prediction. The present results show that it is possible to successfully determinate set of statistical parameters, linked to the impact parameters.