Abstract: An in-line, contactless and non-destructive method for detecting and identifying defects in a moving cardboard structure is provided, as well as the associated system. The cardboard structure is of the type made of layered paper plies, such as cardboard tubes for example. The method includes the steps of emitting acoustic waves with predetermined frequencies toward the moving cardboard structure. The acoustic waves are converted into mechanical waves propagating through the moving cardboard structure. The method also includes a step of capturing the acoustic waves propagated, wherein said captured acoustic waves result from a conversion of the propagated mechanical waves through the moving cardboard structure. The method also provides steps of analyzing the captured acoustic waves; and detecting and identifying defects in the moving laminated cardboard structure based on predetermined propagation properties measured from the captured acoustic waves.

Abstract: An in-line, contactless and non-destructive method for detecting and identifying defects in a moving cardboard structure is provided, as well as the associated system. The cardboard structure is of the type made of layered paper plies, such as cardboard tubes for example. The method includes the steps of emitting acoustic waves with predetermined frequencies toward the moving cardboard structure. The acoustic waves are converted into mechanical waves propagating through the moving cardboard structure. The method also includes a step of capturing the acoustic waves propagated, wherein said captured acoustic waves result from a conversion of the propagated mechanical waves through the moving cardboard structure. The method also provides steps of analyzing the captured acoustic waves; and detecting and identifying defects in the moving laminated cardboard structure based on predetermined propagation properties measured from the captured acoustic waves.

Abstract: Method and apparatus for determining that a pressure field is applied on a structure. A plurality of acoustic waves are generated within the structure using at least one wave generator and a plurality of measurements of the acoustic waves is taken using at least one wave sensor. A pressure field applied to a surface of the structure is determined by processing at least two of the plurality of measurements. The wave generator and the wave sensor may be piezoelectric elements, which may alternate between acting as the wave generator and the wave sensor. Processing the measurements may comprise obtaining a differential measurement value and comparing the value to a threshold. Determining that the pressure field is applied may comprise processing the measurements using a model based on acoustic wave propagation or experimental results. The processing may provide a mapping of the pressure field of an object on the structure.

Abstract: The invention relates to a method for providing a structural condition of a structure, comprising providing an excitation wave generator; providing an excitation wave sensor; injecting an excitation burst wave into the structure using the excitation wave generator; obtaining a measured propagated excitation burst wave using the excitation wave sensor; correlating the measured propagated excitation burst wave with one of a plurality of theoretical dispersed versions of the excitation burst wave; and providing an indication of the structural condition of the structure corresponding to the correlated measured propagated excitation burst wave. The method may offer a better localization of the reflection points and thus of the potential defects present in a structure under inspection, when compared with a group velocity-based or time-of-flight (ToF) approach. The method may be particularly useful for structural health monitoring (SHM) and Non-Destructive Testing (NDT).

Abstract: Method and apparatus for determining that a pressure field is applied on a structure. A plurality of acoustic waves are generated within the structure using at least one wave generator and a plurality of measurements of the acoustic waves is taken using at least one wave sensor. A pressure field applied to a surface of the structure is determined by processing at least two of the plurality of measurements. The wave generator and the wave sensor may be piezoelectric elements, which may alternate between acting as the wave generator and the wave sensor. Processing the measurements may comprise obtaining a differential measurement value and comparing the value to a threshold. Determining that the pressure field is applied may comprise processing the measurements using a model based on acoustic wave propagation or experimental results. The processing may provide a mapping of the pressure field of an object on the structure.

Abstract: The invention relates to a method for providing a structural condition of a structure, comprising providing an excitation wave generator; providing an excitation wave sensor; injecting an excitation burst wave into the structure using the excitation wave generator; obtaining a measured propagated excitation burst wave using the excitation wave sensor; correlating the measured propagated excitation burst wave with one of a plurality of theoretical dispersed versions of the excitation burst wave; and providing an indication of the structural condition of the structure corresponding to the correlated measured propagated excitation burst wave. The method may offer a better localization of the reflection points and thus of the potential defects present in a structure under inspection, when compared with a group velocity-based or time-of-flight (ToF) approach. The method may be particularly useful for structural health monitoring (SHM) and Non-Destructive Testing (NDT).