Random propagation times for ultrasonics through polyethyilene

Low power ultrasonics are used for testing high density polyethylene pipe material. Attenuation and velocity give valuable information on the material in situ and without damages. In this paper we revisit recent data in the frequency band (4,10) megahertz. We prove that propagation is equivalent to random delays following stable probability laws. Moreover, the emergence of a companion noise non-detectable by devices is compliant with the law of conservation of energy. •Section 1 describes data of a paper on polyethylene propagation.•Section 2 explains random propagation times derived by stable probability laws. The model is applied to previous data.•Section 3 shows links with the causality property deduced from Kramers–Krönig relations.•In appendices, we construct simple examples justifying the model.