1. Background to the study

Non-destructive testing covers a range of methods designed to characterize the structures under test, without affecting their integrity. The idea is to determine a characterization tracer, which may be a property (physical, optical, thermal, etc.) or a scalar quantity whose relative variations in relation to a reference value can be monitored.

In general, the main objective of a characterization is to determine the value of a structural property, which is either directly determined by the method, or correlated to a scalar quantity. Determining the quantity then enables us to recalculate the value of the property. It is also possible to estimate the state of wear of a material. Various tests are carried out at different times in the life of the structure. Beforehand, several tracer values must be determined: the value for the new structure and the value for the structure...