Abstract: Method for predictive determination of load, simple or combined, at rupture, of a structure, which includes subjecting the structure to a stress which is equivalent to the load; recording acoustic activity generated by damages suffered in the structure, up until a pre-determined stress threshold; and determining the predictive value of the load at rupture using the recorded acoustic emission based on a relationship linking time to the load.

Abstract: A method and a system for enabling high accuracy measurements to be obtained of the location of a plane separating two media of different densities by using the Compton effect, and application thereof to measuring the thicknesses of layers. A measurement assembly constituted by a transmitter and a receiver of X-rays or gamma rays which are focused in emission and in reception irradiates an elementary volume of said media, and is displaced perpendicularly to the plane between said media, and a fifth signal is calculated representative of the extent by which the derivative of the detected signal relative to the displacement exceeds a threshold, after which the barycenter of displacements corresponding to the most recent sequence of said same-sign fifth signals is calculated, with the displacements being weighted by the corresponding one of said fifth signals.

Abstract: A device is disclosed for measuring the variation of the distance separating the two faces of a layer of solid material by means of ultrasounds, comprising:a generator generating a first alternating electric signal,an electroacoustic transmitting transducer,first coupling means for applying the ultrasonic wave to said layer of material,an electroacoustic receiving transducer,second coupling means for applying said ultrasonic wave to said electroacoustic receiving transducer,means for continuously measuring the variation of the phase-shift of the electric signal emitted by the receiving transducer with respect to said first alternating electric signal, andcomputing means for deriving said distance variation from said phase-shift variation, wherein:said electroacoustic transmitting and receiving transducer, as well as said first and second coupling means are disposed on the same side of said layer of material, andsaid first and second coupling means are solid ultrasonic wave-guides.