The determination of the elastic characteristics of materials is usually done on standard test-samples whose traction strength is tested on test devices from which the force signal is collected, whereas the signals related to longitudinal and transversal strain are collected from extensometer. In case one wishes to determine the elastic characteristics of the materials of some structures that operate in the exploitation field, the previously described methods cannot apply because one cannot draw test-samples from the components of the respective structures. If we consider the fact that the materials of the exploited pieces can modify their elastic characteristics in time, their in-situ determination thus becomes necessary. Such a method is described below and is based on the determination of the speed of the longitudinal and transversal ultrasound waves via the respective materials.
